BACnet MS/TP Driver Manual 0
Driver Manual
FS-8700-73 BACnet MS/TP
MSAsafety.com
Driver Revision: 2.21
Document Revision: 5.A
APPLICABILITY & EFFECTIVITY
Effective for all systems manufactured after February 2021.
BACnet MS/TP Driver Manual 2
MSA Safety
1991 Tarob Court
Milpitas, CA 95035
Website: www.MSAsafety.com
U.S. Support Information:
+1 408 964-4443
+1 800 727-4377
Email: [email protected]
EMEA Support Information:
+31 33 808 0590
Email: smc-support.emea@msasafety.com
BACnet MS/TP Driver Manual 3
Contents
1 Description ........................................................................................................................................ 5
1.1 BTL Mark – BACnet Testing Laboratory .................................................................................. 5
2 Driver Scope of Supply .................................................................................................................... 6
2.1 Supplied by MSA Safety ........................................................................................................... 6
2.2 Provided by the Supplier of 3
rd
Party Equipment ..................................................................... 6
2.3 Optional Items........................................................................................................................... 6
3 Hardware Connections .................................................................................................................... 7
4 Data Array Parameters ..................................................................................................................... 8
5 Client Side Configuration ................................................................................................................ 9
5.1 Client Side Connection Parameters ......................................................................................... 9
5.2 Client Side Node Parameters ................................................................................................. 10
5.3 Client Side Map Descriptor Parameters ................................................................................. 11
5.3.1 FieldServer Specific Map Descriptor Parameters .................................................................. 11
5.3.2 Driver Related Map Descriptor Parameters ........................................................................... 11
5.3.3 Timing Parameters ................................................................................................................. 13
5.4 Map Descriptor Examples ...................................................................................................... 13
5.4.1 COV Specific .......................................................................................................................... 13
6 Configuring the FieldServer as a Server ...................................................................................... 14
6.1 Driver Specific FieldServer Parameters ................................................................................. 14
6.2 Server Side Connection Parameters ...................................................................................... 15
6.3 Server Side Node Parameters................................................................................................ 16
6.4 Server Side Map Descriptor Parameters ................................................................................ 17
6.4.1 FieldServer Specific Map Descriptor Parameters .................................................................. 17
6.4.2 Driver Related Map Descriptor Parameters ........................................................................... 17
6.5 Map Descriptor Examples ...................................................................................................... 20
7 Useful Features .............................................................................................................................. 21
7.1 BACnet Properties .................................................................................................................. 21
7.1.1 BACnet Object Names ........................................................................................................... 21
7.1.2 Virtual Network Number ......................................................................................................... 22
7.1.3 Accessing Data from BACnet Properties Comprising Arrays of Values ................................ 23
7.1.4 FieldServer Implementation of BACnet Priority Arrays .......................................................... 23
7.1.5 Relinquishing Control of a Point as a Client ........................................................................... 24
7.1.6 BACnet State Text Preload .................................................................................................... 25
7.1.7 Factors Determining the Reliability Property .......................................................................... 26
7.1.8 Update Property Function ...................................................................................................... 26
7.1.9 BACnet State Text Preload .................................................................................................... 27
7.1.10 Factors Determining the Reliability Property .......................................................................... 28
7.1.11 Update Property Function ...................................................................................................... 28
7.1.12 Using a .ini File to Set Vendor_ID and Vendor_Name of the Device Object ......................... 29
7.1.13 Srv_Offline_Method Legal Values.......................................................................................... 29
7.2 BACnet Services .................................................................................................................... 30
7.2.1 COV and Intrinsic Reporting .................................................................................................. 30
7.2.2 Specify Read/Write PropertyMultiple Transactions with Linked Map Descriptors ................. 34
7.2.3 Disabling Selected BACnet Services ..................................................................................... 36
7.3 Virtual Router Configuration – Connect a Device to the Local BACnet Segment .................. 37
7.4 Trending Using Trend Log Objects ........................................................................................ 37
7.4.1 Operating Statistics ................................................................................................................ 38
7.4.2 Date and Time Synchronization ............................................................................................. 39
7.5 Writing to Custom Properties on Remote BACnet Devices ................................................... 39
7.6 Intrinsic Reporting for Life Safety Point .................................................................................. 40
BACnet MS/TP Driver Manual 4
8 Troubleshooting ............................................................................................................................. 41
8.1 Debugging a BACnet Connection .......................................................................................... 41
8.2 COV Configuration ................................................................................................................. 41
8.3 BACnet Specific Statistics ...................................................................................................... 41
8.4 BACnet Specific Error Messages ........................................................................................... 42
8.5 BACnet Error Response Decoding ......................................................................................... 42
8.5.1 BACnet Error Class ................................................................................................................ 42
8.5.2 BACnet Error Codes for Error Class Object ........................................................................... 43
8.6 Rediscovering Offline Devices ................................................................................................ 44
8.7 Timeout Errors ........................................................................................................................ 44
8.8 PDU Limit Reached Errors ..................................................................................................... 44
9 Vendor Information ........................................................................................................................ 45
9.1 McQuay .................................................................................................................................. 45
9.2 Liebert ..................................................................................................................................... 45
9.3 Automated Logic Corporation ................................................................................................. 45
9.4 Honeywell EBI ........................................................................................................................ 45
9.5 Using Cimetrics Explorer ........................................................................................................ 45
10 Reference ........................................................................................................................................ 47
10.1 FieldServer Vendor ID ............................................................................................................ 47
10.2 Object_Type Legal Values – Abbreviation Descriptions ........................................................ 47
10.3 Configuring Binary Outputs .................................................................................................... 47
10.4 Property Legal Values ............................................................................................................ 48
10.5 Supported BACnet Object Properties ..................................................................................... 51
10.6 Units ........................................................................................................................................ 54
Description
BACnet MS/TP Driver Manual 5
1 Description
The BACnet Master-Slave/Token-Passing (MS/TP) driver implements a data link protocol that uses the
services of the RS-485 physical layer. See the FieldServer BACnet PIC statement for the level of
conformance that this driver implements.
All information in a BACnet system is represented in terms of objects. The Object_Identifier is a 32-bit code
that identifies the type of Object (also identified by the Object_Type Property) and its "Instance" number,
which together uniquely identify the Object within its BACnet device. Theoretically, a BACnet device could
have over four million Objects of a particular type. The Object_Name is a text string, which has a unique
capability. BACnet devices may broadcast queries for devices that contain Objects with a specific
Object_Name. This can greatly simplify project setup.
BACnet requires one Device Object to be present in every BACnet device. The Device Object makes
information about the device and its capabilities available to other devices on the networks. Before one
BACnet device starts control-related communications with another, it needs to obtain some of the
information presented by the other device's Device Object. Unlike other Objects, the Device Object's
Instance number must be unique across the entire BACnet internetwork because it is used to uniquely
identify the BACnet devices. It may be used to conveniently identify the BACnet device from other devices
during installation.
Standard object types are used to hold real time data and other information. Each Object Type is referenced
by a number, for example 0 represents an Analog Input. See Section 10.2 for abbreviation list.
Each Object consists of a number of prescribed properties, the main property being the Present_Value.
Objects are monitored and controlled through their properties.
The information that follows describes how to expand upon the factory defaults provided in the configuration
files included with the FieldServer.
1.1 BTL Mark – BACnet Testing Laboratory
Go to www.BACnetInternational.net for more information about the BACnet Testing
Laboratory. Click here for the BACnet PIC Statement.
Max Nodes Supported
FieldServer Mode
Nodes
Comments
Client
1
Server
32
The BTL Mark on ProtoNode is a symbol that indicates that a product has passed a
series of rigorous tests conducted by an independent laboratory which verifies that the
product correctly implements the BACnet features claimed in the listing. The mark is a
symbol of a high-quality BACnet product.
Description
BACnet MS/TP Driver Manual 6
2 Driver Scope of Supply
2.1 Supplied by MSA Safety
Part #
Description
Driver Manual
2.2 Provided by the Supplier of 3
rd
Party Equipment
Part #
Description
BACnet Controller(s) on RS-485 Network
2.3 Optional Items
Part #
Vendor/Manufacturer
Description
FS-4301-00
MSA Safety
RS-232 to RS-485 converter
Installing the FieldServer
BACnet MS/TP Driver Manual 7
3 Hardware Connections
Configure the BACnet MS/TP according to manufacturer’s instructions.
The FieldServer is connected to the BACnet MS/TP as shown in connection drawing below.
Configuring the FieldServer
BACnet MS/TP Driver Manual 8
4 Data Array Parameters
Data Arrays are “protocol neutral” data buffers for storage of data to be passed between protocols. It is
necessary to declare the data format of each of the Data Arrays to facilitate correct storage of the relevant
data.
Section Title
Data_Arrays
Column Title
Function
Legal Values
Data_Array_Name
Provide name for Data Array.
Up to 15 alphanumeric
characters
Data_Array_Format
Provide data format. Each Data Array can only take
on one format.
Float, Bit, Uint16,
Uint32, Sint16, Sint32,
Byte
Data_Array_Length
Number of Data Objects. Must be larger than the
data storage area required by the Map Descriptors
for the data being placed in this array.
1-10000
Example
// Data Arrays
Data_Arrays
Data_Array_Name
, Data_Array_Format
, Data_Array_Length
DA_AI_01
, UInt16,
, 200
DA_AO_01
, UInt16
, 200
DA_DI_01
, Bit
, 200
DA_DO_01
, Bit
, 200
Configuring the FieldServer
BACnet MS/TP Driver Manual 9
5 Client Side Configuration
For detailed information on FieldServer configuration, refer to the FieldServer Configuration Manual. The
information that follows describes how to expand upon the factory defaults provided in the configuration
files included with the FieldServer (see “.csv” sample files provided with the FieldServer).
This section documents and describes the parameters necessary for configuring the FieldServer to
communicate with a BACnet MS/TP Server.
The configuration file tells the FieldServer about its interfaces, and the routing of data required. In order to
enable the FieldServer for BACnet MS/TP communications the following three actions must be taken. The
driver independent FieldServer buffers need to be declared in the “Data Arrays” section. The destination
device addresses need to be declared in the “Client Side Nodes” section. And the data required from the
server(s) needs to be mapped in the “Client Side Map Descriptors” section. Details on how to perform these
steps can be found in the following sections.
NOTE: In the following tables, * indicates an optional parameter and bold legal values are default.
5.1 Client Side Connection Parameters
Section Title
Connections
Column Title
Function
Legal Values
Port
Specify which port the device is connected
to the FieldServer.
P1-P2
1
, R1-R2
2
Baud
Specify baud rate.
9600, 19200, 38400,
76800
Parity*
Specify parity.
Odd, Even, None
Data_Bits*
Specify data bits.
7, 8
Stop_Bits*
Specify stop bits.
1, 2
Protocol
Specify protocol used.
BACnet_MSTP
Poll Delay*
Time between internal polls.
0-32000s, 1s
Max_Master*
Specify the highest MAC_Address for
Master nodes. When designing a BACnet
MS/TP network with multiple Master_Node
devices, allocate the MAC_Address
settings on the different devices starting at
1. This will allow specification of a small
Max_Master parameter and hence will
improve overall network performance.
1-127
Connection_Type*
Specify if the connection must be in
Master_Mode or in Slave_Mode.
MSTP_Master_Mode
MSTP_Slave_Mode
MAC_Address
3
Specify the MS/TP MAC Address for this
connection.
0-127 for
MSTP_Master_Mode;
0-254 for
MSTP_Slave_Mode
1
P1 to P2 will require the optional RS-485 converter (Part # 4301-00).
2
Not all ports shown are necessarily supported by the hardware. Consult the appropriate Instruction manual for details of the ports
available on specific hardware.
3
Previously the MAC_Address was set using the System_Node_ID parameter in the Common Information section.
Configuring the FieldServer
BACnet MS/TP Driver Manual 10
Max_Info_Frames
Specify the maximum number of
information frames the connection may
send before it must pass the token.
1-65535
Max_Concurrent_Messages*
Specify at most how many messages
driver can send out, before start waiting for
response.
1 - 65534, 8 (1 means
no concurrent
messaging, i.e. single
active message at any
time)
4
Example:
// Client Side Connections
Connections
Port
, Baud
, Parity
, Data_Bits
, Stop_Bits
, Protocol
, Poll_Delay
, Timeout
R1
, 38400
, None
, 8
, 1
, BACnet_MSTP
, 0.100s
, 30s
5.2 Client Side Node Parameters
Section Title
Nodes
Column Title
Function
Legal Values
Node_Name
Provide name for Node.
Up to 32 alphanumeric characters
Node_ID
Specify the BACnet Device object instance.
0 – 4194303
Protocol
Specify protocol used.
BACnet_MSTP
Port
Specify port.
P1-P25, R1-R26
MAC_Address*
7
Specify the BACnet MS/TP MAC address
for this connection. Configuring the remote
MAC address directly replaces the default
operation (dynamic device binding) using
Who-Is broadcasts. This is useful in
situations where either the network or the
target device do not support dynamic device
binding (e.g. when talking to MS/TP slave
devices). Note that the Device Instance /
Node_ID should not be specified when the
MAC Address is configured directly.
8
0-127 for MSTP_Master_Mode;
0-254 for MSTP_Slave_Mode; -
Network_Number*
Use this parameter if the remote BACnet
MS/TP server device is on another BACnet
network connected via a router.
1-65536 bit positive numbers, 5
Retries*
Number of timeouts before the Node goes
offline.
Any positive integer, 3
4
Using Max_Concurrent_Messages value > 1 could improve communication performance depending upon server implementation. It
is possible that the Server does not support multiple messaging. Try to match this number with the Server's capability.
5
P1 to P2 will require the optional RS-485 converter (Part # 4301-00).
6
Not all ports shown are necessarily supported by the hardware. Consult the appropriate Instruction manual for details of the ports
available on specific hardware.
7
Previously the MAC_Address was set using the System_Node_ID parameter in the Common Information section.
8
Either Node_ID or MAC_Adddress must be specified. If the Server Node supports Who-Is and I-Am then it is better to use the
Node_ID parameter.
Configuring the FieldServer
BACnet MS/TP Driver Manual 11
APDU_Timeout*
The time in milliseconds between
retransmissions of an APDU requiring
acknowledgement for which no
acknowledgment has been received.
10000ms
9
APDU_Retries*
The maximum number of times that an
APDU shall be retransmitted.
3
9
Example
// Client Side Nodes
Nodes
Node_Name
, Node_ID
, Protocol
, Port
, Retries
DEV_1
, 1
, BACnet_MSTP
, R1
, 2
5.3 Client Side Map Descriptor Parameters
5.3.1 FieldServer Specific Map Descriptor Parameters
Column Title
Function
Legal Values
Map_Descriptor_Name
Name of this Map Descriptor. This is used for
Object_Name Property. Ensure that unique
names are configured for each device. Refer
to Section 7.1.
Up to 37 alphanumeric
characters
Data_Array_Name
Name of Data Array where data is to be
stored in the FieldServer.
One of the Data Array
names from Section 4
Data_Array_Offset
Starting location in Data Array.
0 to (Data_Array_Length -1)
as specified in Section 4
Function
Function of Client Map Descriptor.
WRBC, WRBX, ARCS,
RDBC, AWS
5.3.2 Driver Related Map Descriptor Parameters
Column Title
Function
Legal Values
Node_Name
Name of Node to fetch data from.
One of the Node names
specified in Section 5.2
Object_Type
(Alias = Data_Type)
Type of object. Refer to Section 10.2 for more
information.
AI, AO, AV, BI, BO, BV,
MI, MO, MV, NC, LSP,
custom (Section 7.6)
Object_Instance
(Alias = Address)
Instance of the object on the device.
0-4194303
Property
The BACnet property to be read.
Refer to Section 10.4
Data_Array_Low_Scale*
Scaling zero in Data Array.
-32767 to 32767, 0
Data_Array_High_Scale*
Scaling max in Data Array.
-32767 to 32767, 100
Node_Low_Scale*
Scaling zero in Connected Node.
-32767 to 32767, 0
Node_High_Scale*
Scaling max in Connected Node.
-32767 to 32767, 100
9
Permitted Values (APDU_Timeout and APDU_Retries) – The total delay in seconds before giving up on a transmission
(APDU_Timeout/1000 * (APDU_Retries/1000 + 1)) should not exceed 65 seconds.
Configuring the FieldServer
BACnet MS/TP Driver Manual 12
Length*
Used to create an array of sequential
Object_Instances on an Object_Type.
1 to max point count of
the FieldServer, 1
Linked_Map_Descriptors*
This parameter allows the linking of Map
Descriptors to an active read or write Map
Descriptor in order to construct a
ReadPropertyMultiple or WritePropertyMultiple
transaction. Refer to Section 7.2.2.
The name of a
previously defined
active Map Descriptor, -
Array_Index*
When referencing Multistate properties, allows
the user to specify the index of the property to be
read. If 1 is specified, the first one will be read, if
2 is specified, the second will be read, etc. If 0 is
specified, the driver will return the total number
(count) of array items linked to the property. If the
parameter is not specified, a list of all items will
be returned. Refer to Section 7.1.3.
0 to max number of
array items in the
BACnet Property, -
Write_Priority*
Allows the driver to specify the write priority used
to write an output.
1-16, 16
Length*
When the optional Length parameter is set to a
value N, the Map Descriptor will include N
consecutive instances of the specified
Object_Type. For example, if a Map Descriptor
specifies Object_Type, Address 4 and Length 3,
this means that the AO instances 4, 5 and 6 will
be included in the read or write transaction. The
corresponding Data Array values are in
consecutive positions in the Data Array, starting
at the specified Data_Array_Offset.
Any positive integer that
falls between the range
of the
Data_Array_Offset and
the Data_Array_Length
as specified in
Section 4, -;
see Section 7.2.2
COV Specific
If the remote server supports COV-B it is possible to configure the FieldServer BACnet Client to
subscribe to COV updates. This can be done instead of or in addition to periodic reads. The advantage
of using COV is that changed values will be reported within a much shorter time, especially if a large
number of points is being monitored. However, not all BACnet devices support COV, so exercise care
when using this function.
Service
BACnet Point service.
COVSubscribe
Confirmed
Used to select Confirmed or Unconfirmed COV
Notifications.
Yes, No
Function
Set to ARS or AWS to subscribe once on startup,
or to RDBC or WRBC to re-subscribe after each
Scan_Interval.
ARS, AWS, RDBC,
WRBC
COV_Lifetime
Specify the COV subscription lifetime in seconds.
Use a large value to get the benefit of decreased
network communications.
Value in seconds
Scan_Interval
If using RDBC in order to re-subscribe
periodically, set the Scan_Interval to the desired
re-subscription interval. This should be
significantly shorter than COV_Lifetime.
Value in seconds
Configuring the FieldServer
BACnet MS/TP Driver Manual 13
5.3.3 Timing Parameters
Column Title
Function
Legal Values
Scan_Interval*
Rate at which data is polled.
0-32000, 2s
5.4 Map Descriptor Examples
All three examples below are addressing the same Modbus registers:
// Client Side Map Descriptors
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Data_Type
, Object_Instance
, Property
, Scan_Interval
CMD_AI_01
, DA_AI_01
, 0
, Rdbc
, DEV_1
, AI
, 1
, Present_Value
, 20.000s
CMD_AI_02
, DA_AI_01
, 1
, Rdbc
, DEV_1
, AI
, 2
, Present_Value
, 20.000s
CMD_AI_03
, DA_AI_01
, 2
, Rdbc
, DEV_1
, AI
, 3
, Present_Value
, 20.000s
CMD_AO_01
, DA_AO_01
, 0
, Rdbc
, DEV_1
, AO
, 1
, Present_Value
, 30.000s
CMD_AO_02
, DA_AO_01
, 1
, Rdbc
, DEV_1
, AO
, 2
, Present_Value
, 30.000s
CMD_AO_03
, DA_AO_01
, 2
, Rdbc
, DEV_1
, AO
, 3
, Present_Value
, 30.000s
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Data_Type
, Object_Instance
, Property
, Scan_Interval
CMD_DI_01
, DA_DI_01
, 0
, Rdbc
, DEV_1
, BI
, 1
, Present_Value
, 15.000s
CMD_DI_02
, DA_DI_01
, 1
, Rdbc
, DEV_1
, BI
, 2
, Present_Value
, 15.000s
CMD_DI_03
, DA_DI_01
, 2
, Rdbc
, DEV_1
, BI
, 3
, Present_Value
, 15.000s
CMD_DO_01
, DA_DO_01
, 0
, Rdbc
, DEV_1
, BO
, 1
, Present_Value
, 30.000s
CMD_DO_02
, DA_DO_01
, 1
, Rdbc
, DEV_1
, BO
, 2
, Present_Value
, 30.000s
CMD_DO_03
, DA_DO_01
, 2
, Rdbc
, DEV_1
, BO
, 3
, Present_Value
, 30.000s
5.4.1 COV Specific
In this example, Map Descriptor CMD_AI_01_SUB creates and periodically renews the COV subscription.
Map Descriptor CMD_AI_01_RD performs periodic reads of the same object and will also be updated by
COV Notifications received.
Map Descriptor
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Data_Type
CMD_AI_01_SUB
, DA_AI
, 0
, RDBC
, BCU_01
, AI
CMD_AI_01_RD
, DA_AI
, 1
, RDBC
, BCU_01
, AI
, Object_ID
, Service
, COV_Lifetime
, Confirmed
, Scan_Interval
, 0
, COVSubscribe
, 600
, Yes
, 300
, 0
, -
, -
, -
, 30
Configuring the FieldServer
BACnet MS/TP Driver Manual 14
6 Configuring the FieldServer as a Server
For detailed information on FieldServer configuration, refer to the FieldServer Configuration Manual. The
information that follows describes how to expand upon the factory defaults provided in the configuration
files included with the FieldServer (see “.csv” sample files provided with the FieldServer).
This section documents and describes the parameters necessary for configuring the FieldServer to
communicate with a BACnet MS/TP Client.
The configuration file tells the FieldServer about its interfaces, and the routing of data required. In order to
enable the FieldServer for BACnet MS/TP communications the following three actions must be taken. The
driver independent FieldServer buffers need to be declared in the “Data Arrays” section. The FieldServer
virtual node(s) need to be declared in the “Server Side Nodes” section. And the data to be provided to the
client(s) needs to be mapped in the “Server Side Map Descriptors” section. Details on how to perform these
steps can be found in the following sections.
NOTE: In the tables below, * indicates an optional parameter with the bold legal value as default.
6.1 Driver Specific FieldServer Parameters
Section Title
Bridge
Column Title
Function
Legal Values
Title
FieldServer name.
Text
System_Node_ID
If the FieldServer is acting as a BACnet Router by defining multiple
server nodes, the system_node_id sets the BACnet Device
instance of the Router. If the MAC Address is not defined in the
connection section, the system_node_id also sets the MAC
Address of the FieldServer if it is within the range of 0-127.
0-4194303
Example
// FieldServer Driver specific parameters
Bridge
Title
, System_Node_ID
BacNet MSTP Server V1.02a
, 11
Configuring the FieldServer
BACnet MS/TP Driver Manual 15
6.2 Server Side Connection Parameters
Section Title
Connections
Column Title
Function
Legal Values
Port
Specify which port the device is connected to
the FieldServer.
P1-P2
10
, R1-R2
11
Baud*
Specify baud rate.
9600, 19200, 38400,
76800
Parity*
Specify parity.
None, Odd, Even
Data_Bits*
Specify data bits.
7, 8
Stop_Bits*
Specify stop bits.
1, 2
Protocol
Specify protocol used.
BACnet_MSTP
Connection_Type*
Specify if the connection must be in
Master_Mode or in Slave_Mode.
MSTP_Master_Mode
MSTP_Slave_Mode
Max_Master*
Specify the highest possible MAC_Address that
exists on the MS/TP network. Only applicable
for MSTP_Master Mode connections.
12
1-127
Max_Info_Frames*
Specify the maximum number of information
frames the connection may send before it must
pass the token. Only applicable for
MSTP_Master Mode connections.
12
1-65535
MAC_Address
13
Specify the MS/TP MAC address for this
connection.
0-127 for
MSTP_Master_Mode;
0-254 for
MSTP_Slave_Mode
Reliability_Option*
The Reliability_Option parameter selects the
rules by which the BACnet server determines
the reliability property of a BACnet object whose
present value is read from a remote server
node. See Section 7.1.7.
Track_Object_Status,
Track_Node_Status,
Always_Reliable
Net_Addr_Len*
Set the address length of the virtual network
used to connect multiple virtual BACnet devices
to the external network. By default, this address
is 6 bytes long; older FieldServer versions used
2 or 4 bytes, and if a legacy system depends on
a length different to 6, this can be configured
here. Note that since the virtual network
address corresponds directly to the Node ID,
the Node ID values should not exceed the
maximum value that can be encoded in the
number of address bytes specified.
1-6, -
10
P1 to P2 will require the optional RS-485 converter (Part # 4301-00).
11
Not all ports shown are necessarily supported by the hardware. Consult the appropriate Instruction manual for details of the ports
available on specific hardware.
12
For Server configurations, the Max_Master and Max_Info_Frames parameters (or properties) can be overridden from a BACnet
Client by using the “Write Property” command. Note that when the FieldServer is restarted, the default values specified in the
configuration file will be applied.
13
Previously the MAC_Address was set using the System_Node_ID parameter in the Common Information section.
Configuring the FieldServer
BACnet MS/TP Driver Manual 16
Virtual_Network_Number*
Specify a unique network number if there are
multiple virtual Server Nodes. Refer to Section
7.1.2.
1 – 65535, 5
Is_Router
Specifies whether the FieldServer acts as a
router.
No, Yes (if there are
multiple server nodes
the default is Yes, if
there is one then
default is No)
Router_Network_Number*
Sets the network number for the external
BACnet segment that the connection is
physically connected.
1 – 65535, 5
Example
// Server Side Connections
Connections
Port
, Baud
, Parity
, Data_Bits
, Stop_Bits
, Protocol
, Timeout
, Connection_Type
R1
, 38400
, None
, 8
, 1
, BACnet_MSTP
, 30
, MSTP_Master_Mode
6.3 Server Side Node Parameters
Section Title
Nodes
14
Column Title
Function
Legal Values
Node_Name
Provide name for Node.
Up to 31 alphanumeric
characters
Node_ID
BACnet station address of physical Server node.
0 – 4194303
Protocol
Specify protocol used.
BACnet_MSTP
Node_Option*
Enable or disable COV for this Node. Refer to
Section 7.2.1 for further information.
COV_Enable,
COV_Disable, -
Model_Name*
Sets the Model Name Property of the Device
Object.
Up to 32 alphanumeric
characters
Network_Location*
Specifies on which network the virtual node is
located.
-, Local Segment;
refer to Section 7.3
Device_Description
Sets the Description Property of the Device Object.
Any text string of length
up to 40 characters, or a
Data Array name and
start offset that holds the
text string in the following
format: <Data Array
name.offset> e.g.
<DA_AI_01_Desc.0>
Device_Location
Sets the Location Property of the Device Object.
Up to 32 alphanumeric
characters
Disabled_Services*
Certain BACnet Services can be disabled on a
BACnet Server Node when specific requirements
necessitate this. Refer to Section 7.2.3 for more
information.
-, WPM, COV, RPM
14
Port is not declared in the Server Side Nodes.
Configuring the FieldServer
BACnet MS/TP Driver Manual 17
APDU_Timeout*
The time in milliseconds between retransmissions
of an APDU requiring acknowledgement for which
no acknowledgment has been received.
10000ms
15
APDU_Retries*
The maximum number of times that an APDU shall
be retransmitted.
3
15
Srv_Offline_Method*
Controls the system_status property of the device
object.
-, Any_Offline, All_Offline;
refer to Section 7.1.13
Example
// Server Side Nodes
Nodes
Node_Name
, Node_ID
, Protocol
, Node_Option
, Model_Name
Virtual_DEV_11
, 11
, BACnet_MSTP
, COV_Enable
, WBA11M. MSTP
6.4 Server Side Map Descriptor Parameters
6.4.1 FieldServer Specific Map Descriptor Parameters
Column Title
Function
Legal Values
Map_Descriptor_Name
Name of this Map Descriptor. This is used
for Object_Name Property. Refer to
Section 7.1.
Up to 37 alphanumeric
characters
16
Data_Array_Name
Name of Data Array where data is to be
stored in the FieldServer.
One of the Data Array names
from Section 4
Data_Array_Offset
Starting location in Data Array.
0 to (Data_Array_Length-1) as
specified in Section 4
Function
Function of Server Map Descriptor.
Passive
6.4.2 Driver Related Map Descriptor Parameters
Column Title
Function
Legal Values
Node_Name
Name of Node to fetch data from.
One of the Node names
specified in Section 6.3
Object_Type
(Alias = Data_Type)
Data type in Controller. Refer to Section
10.2 for more information.
AI, AO, AV, BI, BO, BV, MI,
MO, MV, NC, LSP (Section
7.6)
Object_Instance
(Alias = Address)
Instance of the Object on the Device.
0-4194303
Data_Array_Low_Scale*
Scaling zero in Data Array.
-32767 to 32767, 0
Data_Array_High_Scale*
Scaling max in Data Array.
-32767 to 32767, 100
Node_Low_Scale*
Scaling zero in Connected Node.
-32767 to 32767, 0
Node_High_Scale*
Scaling max in Connected Node.
-32767 to 32767, 100
Length*
Used to create an array of sequential
Object_Instances on an Object_Type.
1 to max point count of the
FieldServer, 1
15
Permitted Values (APDU_Timeout and APDU_Retries) – The total delay in seconds before giving up on a transmission
(APDU_Timeout/1000 * (APDU_Retries/1000 + 1)) should not exceed 65 seconds.
16
Object_Name values of any length may be written via BACnet (subject only to memory and message length constraints).
Configuring the FieldServer
BACnet MS/TP Driver Manual 18
Units*
The object units.
See Section 10.6 or a Data
Array name and offset can
be used to dynamically
change the units. The value
stored in the offset should
be a valid BACnet unit
enumeration. It should be
configured in the following
format: <Data Array
Name:offset> e.g.
DA_Units:1; No_Units
Active_Text*
17
Specify the Active Text property of the
Object.
Any text string of length up to
40 characters, Active
Inactive_Text*
17
Specify the Inactive Text property of the
Object.
Any text string of length up to
40 characters, Inactive
Relinquish_Default
17
Specify the value to be returned as
Present_Value on startup or when control is
relinquished. Must be specified for outputs
of AO, BO or MO data types; see Section
10.4.
Any Float value
Notification_Class*
Specify the Mapdescriptor_Name of the
Notification_Class Object that manages
Intrinsic Reporting for this Map Descriptor;
see Section 7.2.1.
A Mapdescriptor_Names of
type NC (Notification Class).
Objects are not available to
NC if left out.
Ack_Required*
For a Notification_Class Object, specify
whether EventNotifications require a user
Acknowledgement; see Section 7.2.1.
Yes, No
COV_Increment*
For a Server Map Descriptor of type AO or
AI, initialize the COV_Increment property;
see Section 7.2.1.
Any Float value, 0
Input_alarm_State*
This parameter is required when a BI, BO
or BV Map Descriptor is configured for
alarms, i.e. when a Notification_Class is
specified for the Map Descriptor. It defines
the value (0 or 1) that is to be treated as the
alarm (i.e. off-normal) value.
0, 1 (there is no default)
Description*
Specify the object’s description property
(e.g. Room Temp).
Any text string up to 40
characters or a Data Array
name and start offset that
holds the text string in the
following format: <Data
Array name.offset> (e.g.
<DA_AI_01_Desc.0>)
18
; if
not configured, defaults to
Object_Name
17
See the BACnet DFS to determine if a particular object supports this property.
18
Description values may be written via BACnet (subject only to memory and message length constraints).
Configuring the FieldServer
BACnet MS/TP Driver Manual 19
Update_Property*
The Update_Property Parameter may be
configured on a BACnet Server Map
Descriptor to allow a property other than the
Present_Value to be updated in addition to
the Present_Value when the Data Array
Value changes. Warning: This is a highly
specialized function only to be used under
very particular circumstances by users with
a detailed understanding of BACnet. Refer
to Section 7.1.8.
Present Value,
Relinquish_Default
Process_ID*
The handle of a process within the recipient
device that is to receive the event
notification; see Section 7.2.1.
Any unsigned integer, -
Notification_Class_MD*
This is the Notification Class map descriptor
governing the sending of Event
Notifications (Intrinsic Alarming); see
Section 7.2.1.
Map Descriptor defined per
Section 7.2.1
Min_Pres_Value*
Specify the "Minimum Present Value"
property for an AO Object. This setting can
also be used on AV, even though the AV
object itself does not support the property.
Any floating point value is
legal. If not specified, default
to +- Infinity
19
Max_Pres_Value*
Specify the "Maximum Present Value"
property for an AO Object. This setting can
also be used on AV, even though the AV
object itself does not support the property.
Any floating point value is
legal. If not specified, default
to +- Infinity
19
Low_Alarm
For AI, AO and AV object types this sets
the lower alarm limit.
Any floating point value
High_Alarm
For AI, AO and AV object types this sets
the upper alarm limit.
Any floating point value
Alarm_Deadband*
For AI, AO, and AV types, this is the
amount by which the present value must be
greater than the Low_Alarm limit or less
than the High_Alarm limit for the object to
return to the Normal state and send a to-
normal event.
Any floating point value, 0.0
19
In this implementation, the Min_Pres_Value & Max_Pres_Value properties can be read but not written via BACnet.
Configuring the FieldServer
BACnet MS/TP Driver Manual 20
6.5 Map Descriptor Examples
// Client Side Map Descriptors
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Object_Type
, Object_Instance
, Units
SMD_AI_01
, DA_AI_01
, 0
, Passive
, Virtual_DEV_11
, AI
, 1
, Degrees-Fahrenheit
SMD_AI_02
, DA_AI_01
, 1
, Passive
, Virtual_DEV_11
, AI
, 2
, Degrees-Fahrenheit
SMD_AI_03
, DA_AI_01
, 2
, Passive
, Virtual_DEV_11
, AI
, 3
, Degrees-Fahrenheit
SMD_AO_01
, DA_AO_01
, 0
, Passive
, Virtual_DEV_11
, AO
, 1
, percent-relative-humidity
SMD_AO_02
, DA_AO_01
, 1
, Passive
, Virtual_DEV_11
, AO
, 2
, percent-relative-humidity
SMD_AO_03
, DA_AO_01
, 2
, Passive
, Virtual_DEV_11
, AO
, 3
, percent-relative-humidity
// Client Side Map Descriptors
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Object_Type
, Object_Instance
SMD_DI_01
, DA_DI_01
, 0
, Passive
, Virtual_DEV_11
, BI
, 1
SMD_DI_02
, DA_DI_01
, 1
, Passive
, Virtual_DEV_11
, BI
, 2
SMD_DI_03
, DA_DI_01
, 2
, Passive
, Virtual_DEV_11
, BI
, 3
SMD_DO_01
, DA_DO_01
, 0
, Passive
, Virtual_DEV_11
, BO
, 1
SMD_DO_02
, DA_DO_01
, 1
, Passive
, Virtual_DEV_11
, BO
, 2
SMD_DO_03
, DA_DO_01
, 2
, Passive
, Virtual_DEV_11
, BO
, 3
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Object_Type
SMD_11_AO_03
, DA_AO_01
, 0
, Passive
, Virtual_Dev_11
, AO
, Object_Instance
, Relinquish_Default
, Min_Pres_Value
, Max_Pres_Value
, 03
, 0
, 10
, 20
Additional Information
BACnet MS/TP Driver Manual 21
7 Useful Features
7.1 BACnet Properties
7.1.1 BACnet Object Names
When an external BACnet Client builds a list of Object Names, the BACnet Server Map Descriptor names
determine the BACnet Object Name. If the Map Descriptor length is greater than 1, the Object Name will
be suffixed with the index into the Map Descriptor. For example, if the Map Descriptor name is SMD_AI_01
and the length 3, then the Object Names will be SMD_AI_01[0], SMD_AI_01[1] and SMD_AI_01[2]. The
maximum length of a point Object Name is the same as the maximum Map_Descriptor_Name length. Refer
to Section 6.4.
The Device Object Name is set from either the Node Name or the Model Name, and the maximum length
is determined by the maximum number of characters defined in the legal values column. Refer to Section
6.4.
NOTE: It is important that unique Map Descriptor names are created for each device to ensure
that the Object Names are unique.
Using Tags to Create Unique Device and Object Names
The <device_id> tag can be used to tag the actual device object instance to the end of the specified
Object_Name.
Nodes
Node_Name
, Node_ID
, Protocol
, Node_Option
Dev_MSTP_<device_id>
, 11
, Bacnet_MSTP
, COV_Enable
In the example above the FieldServer will appear as Dev_MSTP_11 when it is discovered on BACnet. The
Map_Descriptor reference to the BACnet node must also include the same <device_id> tag. If the Node_ID
is now changed using the dip-switches, then the Device Object_Name will automatically change with the
same value at the end.
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
Dev_MSTP_<device_id>
, DA_DI_01
, 0
, Server
, Virtual_BCU_<device_id>
, Data_Type
, Object_ID
, Relinquish_Default
, DI
, 1
, -
Additional Information
BACnet MS/TP Driver Manual 22
7.1.2 Virtual Network Number
Whenever there are multiple virtual nodes, the FieldServer interconnects these on a virtual internal network
and acts as a virtual router between this and the external network. Each internal virtual network must be
assigned a network number. The BACnet specification states that this network number must be unique
across the entire BACnet internetwork. The following configuration error is generated when an attempt is
made to reuse the same network number on the same device:
BACnet Router : Error: Network Number 5 has already been used. Configure a unique Virtual_Network_Number
on each BACnet _MSTP Connection
NOTE: Failing to use unique network numbers can lead to routing problems on a BACnet
network.
The Virtual_Network_Number parameter can be used to assign network numbers to the internal virtual
networks associated with each BACnet connection. The defaults will also be unique for the FieldServer
itself, but it is up to the user to ensure that the network number is unique across the entire network. The
error message shown above only arises when the same virtual network number is specified for more than
one connection.
Section Title
Connections
Column Title
Function
Legal
Values
Virtual_Network_Number*
Specify a unique network number if there are multiple virtual
Server nodes.
1-65534, 5
Example
// Server Side Connections
Connections
Adapter
, Protocol
, Virtual_Network_Number
N1
, Bacnet_MSTP
, 5
NOTE: The BACnet driver is not limited to the number of device instances on the Server Side but
caution that using over 200 Device Instances could result in issues with the Who-Is
transaction.
NOTE: If an application demands multiple BACnet/IP Server nodes and multiple BACnet MS/TP
Server Nodes simultaneously, they will at present all appear with the same virtual network
number. This creates a potential conformance problem if there is an external BACnet
router connecting the BACnet/IP and BACnet MS/TP networks to which the FS is also
connected, as duplicate virtual networks with the same network number would then exist
in the BACnet network, which is not permitted. Contact technical support for assistance.
Additional Information
BACnet MS/TP Driver Manual 23
7.1.3 Accessing Data from BACnet Properties Comprising Arrays of Values
Some BACnet Object properties (e.g. Priority_Array) are arrays of values (the Priority_Array property is an
array of 16 values). In order to read a specific array entry, the Array_Index must be specified in the Map
Descriptor. Array_Index is a Client Side Map Descriptor function.
The following example shows a configuration that will read the Priority_Array value at Array_Index 7,
belonging to Analog Output 1.
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Data_Type
, Object_ID
, Property
, Array_Index
CMD_AI_01
, DA_AI_01
, 0
, Rdbc
, DEV_01
, AO
, 1
, Priority_Array
, 7
Details of the relevant BACnet properties and their associated arrays can be found in the BACnet
Protocol Spec.
If no Array_Index is specified, then the entire property (i.e. the entire BACnet Array) is returned.
The Data_Index parameter functions as follows for ReadPropertyMultiple or WritePropertyMultiple
requests when the Client Map Descriptor Length N is greater than 1:
• When an Array_Index is specified, the ReadPropertyMultiple or WritePropertyMultiple request will
iterate through N successive Array_Index values for the given Object and Property (e.g. Priority
Array Index 1 to 16 of Analog Output 1).
• When no Array_Index is specified, the ReadPropertyMultiple or WritePropertyMultiple request will
iterate through N successive Object Instances, reading the specified Property from each
successive object (e.g. Present Value of Analog Output 1 to Analog Output 16).
7.1.4 FieldServer Implementation of BACnet Priority Arrays
When BACnet Output objects are written to the Server side of the FieldServer, an associated write priority
is given to each write value. When the FieldServer receives the write value, it stores it to the Map Descriptor
Priority Array Table at the specified priority. The Priority Array Table is then scanned and the value with the
highest priority is stored to the Data Array location specified by the Map Descriptor.
When a Write “Relinquished” command is received, the value is removed from the Priority Array Table and
the next highest value from the Priority Array Table is stored to the Data Array.
If all values have been “Relinquished” from the Priority Array Table, then the Map Descriptors “Relinquish
Default” value will be stored to the Data Array.
Additional Information
BACnet MS/TP Driver Manual 24
Accessing Priority Array Information
The Priority Array table and its “In_Use” (or Not Relinquished) state are stored internally to every Map
Descriptor and cannot be accessed directly. The information can be accessed indirectly by specifying the
following Data Arrays which will maintain an exact copy of the Priority Array Table for the Map Descriptor.
Section Title
Map_Descriptors
Column Title
Function
Legal Values
DA_Pri_Array
Name of Data Array where the Priority Array Table will be
stored. Location 0 is the Relinquish Default value and
locations 1 to 16 the different entries of the Priority Array
Table.
Up to 16
alphanumeric
characters
DA_Pri_Array_Offset*
Starting location in Data Array.
1-65535, 0
DA_Pri_In_Use
Name of Data Array that indicates if a specific Priority Value
is in use. Location 0 indicates whether the Relinquish
Default has been set and locations 1 to 16 indicate whether
the index is in use (1), or Relinquished (0).
Up to 16
alphanumeric
characters
DA_Pri_In_Use_Offset*
Starting location in Data Array.
1-65535, 0
// Analog Output Map_Descriptor for testing Priority Arrays
Map_Descriptors
Map_Descriptor_Name
, Data_Type
, Object_ID
, Function
, Data_Array_Name
, Data_Array_Index
, Node_Name
, Length
CMD_AOP_1
, AO
, 1
, Passive
, DA_OUT
, 0
, N1 11
, 1
, Relinquish_default
, DA_Pri_Array
, DA_Pri_Array_Offset
, DA_Pri_In_Use
, DA_Pri_In_Use_Offset
, 40.56
, DA_Pri_Array_1
, 0
, DA_Pri_in_use_1
, 0
7.1.5 Relinquishing Control of a Point as a Client
It is possible to relinquish control of a point by writing a null to the correct priority level. The following
example illustrates how this is done.
Map_Descriptors
Map_Descriptor_Name
, Data_Type
, Function
, Scan_Interval
, Data_Array_Name
, Data_Array_Index
CMD AO
, AO
, Rdbc
, 1.0s
, DA AO
, 2
CMD AO Rel
, AO
, Wrbx
, 1.0s
, DA AO
, 3
, Node_Name
, Address
, Length
, Write_Priority
, Service
, N1 1
, 1
, 1
, 7
, -
, N1 1
, 1
, 1
, 7
, Relinquish
In the above example:
• Map_Descriptor_Name CMD AO is a Read Map Descriptor that will write at priority 7 if a write-
through occurs.
• Map_Descriptor_Name CMD AO Rel is a Write-on-Change Map Descriptor that will write a NULL
at priority 7 (i.e. release Priority Array entry 7) when a write occurs.
• Address parameter length must be 1 as shown above.
Additional Information
BACnet MS/TP Driver Manual 25
7.1.6 BACnet State Text Preload
BACnet Multistate Objects have a State_Text property. This property is defined as an array of character
strings representing descriptions of all possible states of the Present_Value. The number of descriptions
matches the number of states defined in the Number_Of_States property. The Present_Value, interpreted
as an integer, serves as an index into the array.
When Multistate Objects are configured on a BACnet server it is necessary to define the State_Text
property. This section illustrates how to define the State_Text character strings and how to associate these
definitions with Multistate Server Map Descriptors.
The maximum permitted length of any State_Text string is 50 characters.
Method 1 – Using an Offset/User Table
//set up a look up table
Offset_Table
Offset_Table_Name
, Table_String
, Table_Index_Value
FIRE_ALRM_TEXT
, SYSTEM READY
, 1
FIRE_ALRM_TEXT
, ALARM
, 2
FIRE_ALRM_TEXT
, MAINTENANCE
, 3
FIRE_ALRM_TEXT
, OFF-LINE
, 4
FIRE_ALRM_TEXT
, IN SERVICE
, 5
FIRE_ALRM_TEXT
, OTHER
, 6
NOTE: Valid entries for Table_Index_Value are integers of 1 to 100. Anything larger will be either
truncated and/or omitted.
NOTE: The Offset_Table_Name can be up to 16 alphanumeric characters.
Data_Arrays
Data_Array_Name
, Data_Format
, Data_Array_Length
DA_MI_01
, UINT16
, 100
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Data_Type
, Object_ID
, Length
, State_Text_Array
CMD_MI_01
, DA_MI_01
, 0
, Passive
, N1 11
, MI
, 1
, 1
, Fire_Alrm_Text
Method 2 – Using a Single Data Array
Data_Arrays
Data_Array_Name
, Data_Format
, Data_Array_Length
DA_MI_01
, UINT16
, 100
DA_STATE_TXT
, BYTE
, 200
Preloads
Data_Array_Name
, Preload_Data_Value
, Preload_Data_Format
, Preload_Data_Index
DA_STATE_TXT
, MyState1 MyState2 MyState3 MyState4 MyState5 MyState6
, String
, 0
Map_Descriptors
Map_Descriptor_Name
, Data_Type
, Object_ID
, Function
, Data_Array_Name
, Node_Name
, Length
, State_Text_Array
CMD_MI_01
, MI
, 1
, Passive
, DA_MI_01
, N1 11
, 1
, Da_State_Txt
Additional Information
BACnet MS/TP Driver Manual 26
Using Intrinsic Reporting for a Multistate Value
To use Intrinsic Reporting for a Multistate value, it is necessary to classify each of the states as either
Normal, Alarm or Trouble. This is done by adding another column to the Offset_Table, called
Table_User_Value. Each state is then classified by inserting one of the following values in its row:
0 = normal
1 = alarm
2 = fault
//set up a look up table
Offset_Table
Offset_Table_Name
, Table_String
, Table_Index_Value
, Table_User_Value
FIRE_ALRM_TEXT
, SYSTEM READY
, 1
, 0
FIRE_ALRM_TEXT
, ALARM
, 2
, 1
FIRE_ALRM_TEXT
, MAINTENANCE
, 3
, 2
FIRE_ALRM_TEXT
, OFF-LINE
, 4
, 2
FIRE_ALRM_TEXT
, IN SERVICE
, 5
, 0
FIRE_ALRM_TEXT
, OTHER
, 6
, 2
NOTE: The state value (Table_Index_Value) is an enumerated value starting at 1. Zero is not a
valid value, but since many client side configurations will wake up with values of zero, the
BACnet server will treat a value of zero as a normal value (not as an alarm or fault value).
7.1.7 Factors Determining the Reliability Property
The Reliability Property of a BACnet object in a Server configuration is determined as follows:
• For Multistate Inputs, Outputs and Values, the Reliability property is set to
MULTI_STATE_FAULT (9) when the Present_Value of the object corresponds to an entry in the
Fault_Values property of the object, as configured by the State_Text table in the configuration file.
• For all object types, the Reliability property is set to COMMUNICATIONS_FAILURE (12) when
the responsible Server Node is offline.
• When neither Condition 1 nor Condition 2 is met, the Reliability property is set to
NO_FAULT_DETECTED (0)
7.1.8 Update Property Function
The Update_Property parameter may be configured on a BACnet Server Map Descriptor in order to allow
a property other than the Present_Value to be updated in addition to the Present_Value when the Data
Array value changes.
NOTE: This is a highly specialized function only to be used under very particular circumstances,
by users with a detailed understanding of BACnet and of what is to be achieved.
Supported Values
• Present_Value (default operation)
• Relinquish_Default
Additional Information
BACnet MS/TP Driver Manual 27
7.1.9 BACnet State Text Preload
BACnet Multistate Objects have a State_Text property. This property is defined as an array of character
strings representing descriptions of all possible states of the Present_Value. The number of descriptions
matches the number of states defined in the Number_Of_States property. The Present_Value, interpreted
as an integer, serves as an index into the array.
When Multistate Objects are configured on a BACnet server it is necessary to define the State_Text
property. This section illustrates how to define the State_Text character strings and how to associate these
definitions with Multistate Server Map Descriptors.
The maximum permitted length of any State_Text string is 50 characters.
Method 1 – Using an Offset/User Table
//set up a look up table
Offset_Table
Offset_Table_Name
, Table_String
, Table_Index_Value
FIRE_ALRM_TEXT
, SYSTEM READY
, 1
FIRE_ALRM_TEXT
, ALARM
, 2
FIRE_ALRM_TEXT
, MAINTENANCE
, 3
FIRE_ALRM_TEXT
, OFF-LINE
, 4
FIRE_ALRM_TEXT
, IN SERVICE
, 5
FIRE_ALRM_TEXT
, OTHER
, 6
NOTE: Valid entries for Table_Index_Value are integers of 1 to 100. Anything larger will be either
truncated and/or omitted.
NOTE: The Offset_Table_Name can be up to 16 alphanumeric characters.
Data_Arrays
Data_Array_Name
, Data_Format
, Data_Array_Length
DA_MI_01
, UINT16
, 100
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Data_Type
, Object_ID
, Length
, State_Text_Array
CMD_MI_01
, DA_MI_01
, 0
, Passive
, N1 11
, MI
, 1
, 1
, Fire_Alrm_Text
Method 2 – Using a Single Data Array
Data_Arrays
Data_Array_Name
, Data_Format
, Data_Array_Length
DA_MI_01
, UINT16
, 100
DA_STATE_TXT
, BYTE
, 200
Preloads
Data_Array_Name
, Preload_Data_Value
, Preload_Data_Format
, Preload_Data_Index
DA_STATE_TXT
, MyState1 MyState2 MyState3 MyState4 MyState5 MyState6
, String
, 0
Map_Descriptors
Map_Descriptor_Name
, Data_Type
, Object_ID
, Function
, Data_Array_Name
, Node_Name
, Length
, State_Text_Array
CMD_MI_01
, MI
, 1
, Passive
, DA_MI_01
, N1 11
, 1
, Da_State_Txt
Additional Information
BACnet MS/TP Driver Manual 28
Using Intrinsic Reporting for a Multistate Value
To use Intrinsic Reporting for a Multistate value, it is necessary to classify each of the states as either
Normal, Alarm or Trouble. This is done by adding another column to the Offset_Table, called
Table_User_Value. Each state is then classified by inserting one of the following values in its row:
0 = normal
1 = alarm
2 = fault
//set up a look up table
Offset_Table
Offset_Table_Name
, Table_String
, Table_Index_Value
, Table_User_Value
FIRE_ALRM_TEXT
, SYSTEM READY
, 1
, 0
FIRE_ALRM_TEXT
, ALARM
, 2
, 1
FIRE_ALRM_TEXT
, MAINTENANCE
, 3
, 2
FIRE_ALRM_TEXT
, OFF-LINE
, 4
, 2
FIRE_ALRM_TEXT
, IN SERVICE
, 5
, 0
FIRE_ALRM_TEXT
, OTHER
, 6
, 2
NOTE: The state value (Table_Index_Value) is an enumerated value starting at 1. Zero is not a
valid value, but since many client side configurations will wake up with values of zero, the
BACnet server will treat a value of zero as a normal value (not as an alarm or fault value).
7.1.10 Factors Determining the Reliability Property
The Reliability Property of a BACnet object in a Server configuration is determined as follows:
• For Multistate Inputs, Outputs and Values, the Reliability property is set to
MULTI_STATE_FAULT (9) when the Present_Value of the object corresponds to an entry in the
Fault_Values property of the object, as configured by the State_Text table in the configuration file.
• For all object types, the Reliability property is set to COMMUNICATIONS_FAILURE (12) when
the responsible Server Node is offline.
• When neither Condition 1 nor Condition 2 is met, the Reliability property is set to
NO_FAULT_DETECTED (0)
7.1.11 Update Property Function
The Update_Property parameter may be configured on a BACnet Server Map Descriptor in order to allow
a property other than the Present_Value to be updated in addition to the Present_Value when the Data
Array value changes.
NOTE: This is a highly specialized function only to be used under very particular circumstances,
by users with a detailed understanding of BACnet and of what is to be achieved.
Supported Values
• Present_Value (default operation)
• Relinquish_Default
Additional Information
BACnet MS/TP Driver Manual 29
Mode of Operation When Used for the Relinquish_Default Property
When the FieldServer starts up, the standard BACnet operation for AO, AV, BO and BV objects is that the
Present_Value of the object is set to the configured Relinquish_Default value. This may not be desirable in
Gateway situations where the BACnet communications module (i.e. the FieldServer) may restart
independently of the controller with the physical outputs.
Instead, it is possible to use the Update_Property setting to initialize the Relinquish_Default property using
the actual field Present_Value read from the Client Side device, so that a restart achieves two important
outcomes:
• The Client side outputs are not modified
• The current state of the Client Side output can be read via the Relinquish_Default property. This
is especially useful since the BACnet specification makes no provision for Feedback_Values on
analog objects
Depending on the function of the Client Side Map Descriptor there are slightly differing behaviors.
• RDBC – If the Client Side Map Descriptor is configured with the RDBC function, then every read
operation will cause the Relinquish_Default property on the BACnet Server side to be updated to
match the new Present_Value.
• ARS (recommended) – If the Client Side Map Descriptor is configured with the ARS function, then
only the startup read operation (which occurs on FieldServer restart, or if the Client Side Node has
gone offline and is being recovered) will cause the Relinquish_Default property on the BACnet
Server side to be updated to match the new Present_Value.
NOTE: This function cannot yet be used in conjunction with Complex data types.
Update Property Configuration Example
Map_Descriptors
Map_Descriptor_Name
, Function
, Data_Array_Name
, Data_Array_Index
, Node_Name
, Data_Type
AOP1
, Passive
, DA AOP
, 0
, NN 01
, AO
, Address
, Length
, Relinquish_Default
, Update_Property
, 1
, 1
, 10
, Relinquish_Default
7.1.12 Using a .ini File to Set Vendor_ID and Vendor_Name of the Device Object
The vendor.ini file can be used to change the BACnet Vendor Name and Vendor ID if desired. A file with
the following format must be created and downloaded to the FieldServer using the FS-GUI (Setup->File
Transfer->General Tab).
vendor_name = Sierra Monitor Corporation
vendor_id = 37
NOTE: Changing the Vendor_ID and Vendor_Name on FieldServer BTL approved products may
disqualify them from the BTL approval.
7.1.13 Srv_Offline_Method Legal Values
Legal Value
Description
-
Operational
All_Offline
'Non-Operational' if all of the linked Client Side nodes are offline, otherwise 'Operational'
Any_Offline
'Non-Operational' if any of the linked Client Side node is offline, otherwise 'Operational'
Additional Information
BACnet MS/TP Driver Manual 30
7.2 BACnet Services
7.2.1 COV and Intrinsic Reporting
The COV (Change of Value) and Intrinsic Reporting services are two distinct ways in which point values
can be reported to a client workstation as they change in an event-driven opposed to a polling method. This
can increase performance dramatically compared to using a polling method alone. This also reduces
network traffic significantly.
For BACnet MS/TP, only MS/TP Master Nodes support COV and Intrinsic Reporting.
The services are suited to different purposes:
• COV is suited to value updates. On analog points the sensitivity can be set using the
COV_Increment property. Only changes larger than the COV_Increment value will be reported.
The value specified for the COV_Increment is not affected by Map Descriptor scaling parameters,
ie. If the COV_Increment=1 the value in the Data Array must change by at least 1 for a COV
notification to be sent, even if the Data Array Values are scaled.
• Intrinsic Reporting is used for alarming. It is implemented via Notification_Class objects, which
can receive subscriptions from client workstations that add themselves to the RecipientList
property of a Notification_Class object. Notifications are done using ConfirmedEventNotification
or UnconfirmedEventNotification. Intrinsic Reporting also allows for alarms to be acknowledged
(using the AcknowledgeAlarm service) and for all subscribed client workstations to be notified of
alarm acknowledgements (using EventNotifications of type ACK_NOTIFICATION).
Notes on COV Configuration
• COV functionality is not enabled by default for MS/TP. The Node_Option parameter can be
configured to enable or disable COV. An example configuration is presented in the Node
Configuration example below. Systems using BACnet/IP or BACnet/Ethernet to BACnet/MS/TP
routers may not function reliably if COV functionality is enabled as the router will make the MS/TP
device appear as a BACnet/IP or BACnet/Ethernet device, which could lead the BACnet
Workstation to expect unrealistic throughput performance when subscribing to multiple points. It
is recommended only to enable COV functionality on MS/TP systems if the Client device
communicates directly via MS/TP, or if the user knows that the throughput issue will not arise.
• COV functionality (SubscribeCOV service) only applies to the Present_Value and
Status_Flags properties of BACnet Objects - the SubscribeCOVProperty service is not
supported by the FieldServer. COV only works for BACnet Map Descriptors with length set to 1.
If length is not specified, then it defaults to 1, so this is only a problem where length has been
specified as greater than 1.
• For analog Server Map Descriptors, the user may optionally configure a COV_Increment
value to adjust the reporting threshold. If it is not set the COV_Increment defaults to zero.
• COV Notifications are generated for all data objects for which a remote client has issued a
SubscribeCOV-Request. The SubscribeCOV-Request regulates whether Notifications are
Confirmed or Unconfirmed. The remote Client may also write the COV_Increment property in
order to control the deadband for changes in analog values. The COV_Increment property can be
initialized via the configuration file by setting the COV_Increment Map Descriptor Property. The
value set by the configuration is an initial value that is loaded on startup. It would be replaced by
any new value written by the Client.
Additional Information
BACnet MS/TP Driver Manual 31
Notes on Intrinsic Reporting Configuration
• Intrinsic Reporting is managed by Notification Class objects. At least one Notification Class object
must be configured for Intrinsic Reporting to work.
• Each Data_Object that is to be monitored by Intrinsic Reporting must be linked to a Notification
Class object via the Notification_Class Map Descriptor Property. For analog points alarm limits
must be set up, and for binary points, the Input_Alarm_State (specifying which binary value (0 or
1) to regard as the Alarm state) must be set up.
• The Notification_Class object contains properties that allow a client workstation to modify rules
governing event reporting, such as Event_Type, days of week, start and end times etc.
• The RecipientLists are not stored permanently but are kept in volatile memory, and subscriptions
must be renewed on system restart.
• A permanent static RecipientList may be configured directly on the FieldServer, eliminating the
need for a remote workstation to modify the RecipientList in order to receive Event Notifications.
Using this option makes the RecipientList read-only, i.e. it can then only be modified via the
FieldServer config.csv file. Refer to the Priority of Intrinsic Alarming section below.
• The Event_Enable property is required for any object supporting Intrinsic Alarming. This property
is supported, but to save memory is only instantiated if a point is configured for alarming i.e. if it is
set up with a reference to a Notification Class map descriptor.
• These parameters are not configurable but will default to the values listed by the customer:
o Valid Days – Mon-Sun
o Transactions – all
o Notify_Type – confirmed
• The config can be verified by viewing the driver aspect of the BACnet connection. The following
listing of Recipient_List entries should be viewable:
Recipient List - Notification Class BAC_NC_P1 [Instance 1]
Object Inst: 10
Recipient Address Unknown
From/To Time: 00:00.00 - 23:59.59
Valid Days: Mon,Tue,Wed,Thu,Fri,Sat,Sun
Process ID: 12345
Confirmed: Yes
Transitions: To-Off-Normal To-Fault To-Normal
• The Recipient Address will be shown as unknown until the FieldServer has discovered the device
specified by the Object Instance using a Who-Is broadcast. Once discovered this will show the
BACnet MAC Address of the recipient device.
Node Configuration Example – Enable or Disable COV
Nodes
Node_Name
, Node_ID
, Protocol
, Node_Option
Virtual_Dev_11
, 11
, BACnet_MSTP
, COV_Disable
Additional Information
BACnet MS/TP Driver Manual 32
Map Descriptor Example – COV
// Change of Value
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Data_Type
, Object_ID
, Ack_Required
SMD_NC_01
, DA_NC_01
, 0
, Passive
, Virtual_Dev_11
, NC
, 01
, -
Map_Descriptors
Map_Descriptor_Name
, Description
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Data_Type
, Object_ID
, Relinquish_Default
SMD_AI_01
, Room Temp
, DA_AI_01
, 0
, Passive
, Virtual_Dev_11
, AI
, 01
, -
, State_Text_Array
, Notification_Class
, High_Alarm
, Low_Alarm
, Input_Alarm_State
, Confirmed
, COV_Increment
, -
, SMD_NC_01
, 100
, 10
, -
, Yes
, 1.0
Map Descriptor Example – Intrinsic Reporting
// Notification class Objects
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Object_Type
, Object_Instance
, Ack_Required
SMC_NC_01
, DA_NC_01
, 0
, Passive
, Virtual_DEV_11
, NC
, 1
, Yes
SMC_NC_02
, DA_NC_01
, 1
, Passive
, Virtual_DEV_11
, NC
, 2
, No
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Object_Type
, Object_Instance
, Notification_Class
SMD_AI_01
, DA_AI_01
, 0
, Passive
, Virtual_DEV_11
, AI
, 1
, SMC_NC_01
SMD_AO_01
, DA_AO_01
, 0
, Passive
, Virtual_DEV_11
, AO
, 1
, SMC_NC_02
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Object_Type
, Object_Instance
, Notification_Class
SMD_DI_01
, DA_DI_01
, 0
, Passive
, Virtual_DEV_11
, BI
, 1
, SMC_NC_01
SMD_DO_01
, DA_DO_01
, 0
, Passive
, Virtual_DEV_11
, BO
, 1
, SMC_NC_02
Setting the Priority of Intrinsic Alarming
Section Title
Map_Descriptors
Column Title
Function
Legal Values
Pri_To_Off_Normal*
Priority for off normal events.
Refer to Priority Value table below
Pri_To_Normal*
Priority for normal events.
Refer to Priority Value table below
Pri_To_Fault*
Priority for faults.
Refer to Priority Value table below
A BACnet EventNotification message contains a Priority field indicating the priority of the event being
reported. The Priority values to be used are configured via the Priority property of the Notification Class
object, using the configuration file parameters Pri_to_offnormal, Pri_to_normal and Pri_to_fault, which
determine the priorities to be used respectively for all to-off_normal, to-normal and to-fault transitions
reported via the Notification Class object.
Choose priority values as shown below:
Alarm and Event Priority
Network Priority
00-63
Life Safety Message
64-127
Critical Equipment Message
128-191
Urgent Message
192-255
Normal Message
Additional Information
BACnet MS/TP Driver Manual 33
Map Descriptor Example – Set up a Permanent Static Recipient List
A permanent static RecipientList may be configured directly on the FieldServer, eliminating the need for a
remote workstation to modify the RecipientList in order to receive Event Notifications. Using this option
makes the RecipientList read-only, it can then only be modified via the FieldServer config.csv file.
This is done by adding an Event_Receiver section to the config.csv. This section must appear after the
definition and all other references to the relevant Notification Class object.
In the Map Descriptor example below, the Notification Class map descriptor governs the sending of Event
Notifications (Intrinsic Alarming).
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Object_Type
, Object_Instance
, Ack_Required
BAC_NC_P1
, DA_NC_01
, 0
, Passive
, Virtual_DEV_11
, NC
, 1
, No
Notification Class Objects are configured as Map Descriptors. Each Notification Class Object maintains a
RecipientList Property which may contain multiple destinations. Each destination is configured as an
Event_Receiver after the relevant Notification Class Object has been configured.
The example below has a BACnet Object that will report its alarms via the Notification Class map descriptor
BAC_NC_P1.
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Offset
, Function
, Node_Name
, Object_Type
CMD_AI_01
, DA_AI_01
, 10
, Passive
, Virtual_DEV_11
, AI
, Object_Instance
, Notification_Class
, Low_Alarm
, High_Alarm
, 1
, BAC_NC_P1
, 20
, 30
The Event_Receiver example below sets up RecipientList entries for the defined Notification Class map
descriptor. It must appear at the end of the configuration, after all other references to the Notification Class
map descriptor.
Event_Receiver
Node_Name
, Node_ID
, Protocol
, Process_ID
, Notification_Class_MD
, Adapter
OWS_01
, 10
, BACnet_MSTP
, 12345
, BAC_NC_P1
, N1
OWS_02
, 12
, BACnet_MSTP
, 56789
, BAC_NC_P1
, N1
NOTE: Each Event_Receiver node can only be associated with a single notification class map
descriptor. To work around this, configure a different node name for each entry.
Additional Information
BACnet MS/TP Driver Manual 34
7.2.2 Specify Read/Write PropertyMultiple Transactions with Linked Map Descriptors
The ReadPropertyMultiple (RPM) and WritePropertyMultiple (WPM) BACnet services allow many objects
and attributes to be read and written in a single transaction. Since FieldServer Map Descriptors can only
refer to a single object type and address range, an RPM or WPM transaction can be constructed by
linking multiple Map Descriptors. This is done using the following components:
• An active read or write Map Descriptor that defines the behavior of the RPM or WPM transaction
via: Function (for example – Rdbc, Arcs, Wrbc, Wrbx), Scan_interval, Timeout and Length.
• Any number of Linked Map Descriptors specifying additional objects and data array locations to
be included in the transaction. Each Linked Map Descriptor is specified with the following
settings:
o Linked_Map_Descriptor – This is a reference by name to the active Map Descriptor described
above, which controls the transaction
o Function – Must specify “Passive_Client” if linked
o Length
The number of Linked Map Descriptors is limited by the maximum message length allowed for the
BACnet driver in question. When too many Map Descriptors have been linked, a
SEGMENTATION_NOT_SUPPORTED error message will be generated on the first poll attempt. This
message will recommend splitting the RPM or WPM transaction into multiple transactions.
DRV->BACnet : Linked Map Desc. "CMD_WPM" is too long.
Message Segmentation not supported.
Please split the transaction into multiple Linked Map Descriptors.
Example
Map_Descriptors
Map_Descriptor_Name
, Object_Type
, Property
, Function
, Data_Array_Name
, Data_Array_Offset
, Node_Name
CMD WPM
, AO
, -
, Wrbc
, DA WPM
, 0
, N1 1
, Address
, Length
, Write_Priority
, Linked_Map_Descriptor
, 1
, 2
, 7
, -
For the example above, configure an active read or write Map Descriptor and give it a unique name.
This Map Descriptor will be referred to by all other Map Descriptors forming part of the multiple property
transaction.
Map_Descriptor_Name
, Object_Type
, Property
, Function
, Data_Array_Name
, Data_Array_Offset
, Node_Name
CMD WPM 1
, AO
, -
, Passive_Client
, DA WPM
, 3
, N1 1
CMD WPM 2
, AO
, -
, Passive_Client
, DA WPM
, 7
, N1 1
CMD WPM 3
, Device
, Max_Master
, Passive_Client
, DA WPM
, 12
, N1 1
CMD WPM 4
, Device
, Max_Info_Frames
, Passive_Client
, DA WPM
, 13
, N1 1
CMD WPM 5
, BO
, -
, Passive_Client
, DA BOP
, 0
, N1 1
, Address
, Length
, Write_Priority
, Linked_Map_Descriptor
, 4
, 3
, 8
, CMD WPM
, 8
, 4
, 10
, CMD WPM
, 1
, 1
, 10
, CMD WPM
, 1
, 1
, 10
, CMD WPM
, 0
, 10
, 11
, CMD WPM
For the example above:
• Configure a Map Descriptor for each Object and Property. These are component Map Descriptors
forming part of the composite Map Descriptor CMD WPM shown in the first example.
• Set the function to Passive_Client.
• Set Linked_Map_Descriptor to the name of the active read or write Map Descriptor governing the
transaction.
Additional Information
BACnet MS/TP Driver Manual 35
// ReadPropertyMultiple
Map_Descriptors
Map_Descriptor_Name
, Object_Type
, Property
, Function
, Data_Array_Name
, Data_Array_Index
, Node_Name
CMD RPM
, AO
, -
, Rdbc
, DA RPM
, 9
, N1 1
, Address
, Length
, Write_Priority
, Linked_Map_Descriptor
, 1
, 2
, -
, -
Map_Descriptor_Name
, Object_Type
, Property
, Function
, Data_Array_Name
, Data_Array_Index
, Node_Name
CMD RPM 3
, Device
, Max_master
, Passive_Client
, DA RPM
, 0
, N1 1
CMD RPM 4
, Device
, Max_Info_Frames
, Passive_Client
, DA RPM
, 1
, N1 1
CMD RPM 2
, AO
, -
, Passive_Client
, DA RPM
, 2
, N1 1
CMD RPM 1
, AO
, -
, Passive_Client
, DA RPM
, 6
, N1 1
, Address
, Length
, Write_Priority
, Linked_Map_Descriptor
, 1
, 1
, -
, CMD RPM
, 1
, 1
, -
, CMD RPM
, 8
, 4
, -
, CMD RPM
, 4
, 3
, -
, CMD RPM
In the example above, these map descriptors form part of the read transaction defined by Map
Descriptor CMD RPM above.
NOTES:
• For the Present_Value property it is permissible to set a Map Descriptor length >1. This will cause
a read of the Present_Value property of consecutive BACnet objects of the type defined by this
Map Descriptor.
• The number of properties that can be read or written at once is limited by the maximum APDU
message length.
• Message segmentation is not supported.
Additional Information
BACnet MS/TP Driver Manual 36
7.2.3 Disabling Selected BACnet Services
Certain BACnet services can be disabled on a BACnet Server Node when specific requirements necessitate
this:
COV – Certain BACnet MS/TP routers struggle to keep up with the bidirectional traffic that can result from
many COVSubscribe requests in quick succession. In this case, better results might be obtained by
turning COV off.
WritePropertyMultiple (WPM) – When the user requires writes to the BACnet Server to be acknowledged
only once Client Side writes have succeeded, WPM is turned off.
ReadPropertyMultiple (RPM) – This disables read property multiple service. When the BACnet master
sends an RPM request the FieldServer will respond with unsupported service.
These services can be disabled individually or together by listing them under the optional
"Disabled_Services" parameter of the Node configuration section, separated by a space if more than one
function is listed. When a service has been disabled, the BACnet Server Node will reject a corresponding
service request with the reason “Unrecognized Service”.
The following values may be used under Disabled_Services:
• WPM (disable support for the WritePropertyMultiple service)
• RPM (disable support for the ReadPropertyMultiple service)
• COV (disable support for the SubscribeCOV service)
See below for examples:
Disable WPM only
Nodes
Node_Name
, Node_ID
, Protocol
, Disabled_Services
NN 01
, 1
, Bacnet_IP
, WPM
Disable COV only
Nodes
Node_Name
, Node_ID
, Protocol
, Disabled_Services
NN 02
, 2
, Bacnet_IP
, COV
Disable WPM and COV
Nodes
Node_Name
, Node_ID
, Protocol
, Disabled_Services
NN 03
, 3
, Bacnet_IP
, WPM COV
Additional Information
BACnet MS/TP Driver Manual 37
7.3 Virtual Router Configuration – Connect a Device to the Local BACnet Segment
When the FieldServer is configured with multiple BACnet Devices (Nodes) it creates an internal, virtual
BACnet segment and acts as a virtual router in order to make all the Devices individually addressable via
a single external MAC Address.
However, some 3rd party BACnet utilities depend on the presence of a BACnet Device directly on the
local BACnet segment (i.e. not on the internal, virtual segment) to be able to discover the FieldServer. A
local BACnet device can be created especially for this purpose as shown in the example below.
Nodes
Node_Name
, Node_ID
, Protocol
, Network_Location
Virtual_Dev_11
, 11
, Bacnet_MSTP
, Local_Segment
Virtual_Dev_12
, 12
, Bacnet_MSTP
, -
In the example, Virtual_Dev_11 will appear on the local BACnet segment, whereas Virtual_Dev_12 will
appear on a remote BACnet segment identified by the Virtual_Network_Number assigned to the
FieldServer. Only one Node may be configured to appear on the Local Segment.
7.4 Trending Using Trend Log Objects
The FieldServer BACnet driver has been updated to support trending using Trend Log objects. A Map
Descriptor is required for each Trend log to be added to the device. The following parameters are specific
to this application.
Section Title
Map Descriptors
Column Title
Function
Legal Values
Log_Data_Array
The Data Array containing the data which
the Trend Log will log.
One of the specified Data
Arrays
Log_Data_Array_Index
The position in the Data Array of the data
value to be logged.
0 to (Data_Array_Length -1), -
Log_Buffer_Size*
The maximum number of records that will
be kept in the log buffer. This should be
limited due to the size constraints of the
disk.
0 - 65535 log entries
Log_Interval*
How often a record will be stored, specified
in seconds.
4 - 4294967295
Log_Enable*
This setting initializes the Enable property
of the Trend Log at start-up. Logging only
takes place while Enable is True (“Yes”).
Note that this property is writable from
BACnet, the user has the option to set it to
“No” in the configuration file and allow the
BACnet Client to set the Enable property as
required.
Yes, No
Additional Information
BACnet MS/TP Driver Manual 38
NOTE:
• The Client will need to read the log every “Log Interval x Log Buffer Size” to prevent losing data
(e.g. 500 records x 4 seconds / record = 2000 seconds = 33.3 Minutes).
• In this version, the Stop_When_Full property is not writable or configurable and is set to False.
// Server Side Map Descriptors
Map_Descriptors
Map_Descriptor_Name
, Data_Array_Name
, Data_Array_Index
, Function
, Node_Name
, Data_Type
, Address
Trend Log 1
, DA_TREND
, 0
, Passive
, BTU METER
, Trend_Log
, 0
Trend Log 2
, DA_TREND
, 1
, Passive
, BTU METER
, Trend_Log
, 1
Trend Log 3
, DA_TREND
, 2
, Passive
, BTU METER
, Trend_Log
, 2
Trend Log 4
, DA_TREND
, 3
, Passive
, BTU METER
, Trend_Log
, 3
, Log_Data_Array
, Log_Data_Array_Index
, Log_Buffer_Size
, Log_Interval
, Log_Enable
, DA_AI_01
, 0
, 500
, 4
, Yes
, DA_AI_01
, 1
, 500
, 4
, Yes
, DA_AI_01
, 2
, 500
, 4
, Yes
, DA_AI_01
, 3
, 500
, 4
, Yes
7.4.1 Operating Statistics
The following stats were added for diagnosing the operation of the Trend Log, they can be viewed with FS-
GUI.
BACnet Connection Stats
Stat
Description
Pending Trend Log Writes
The number of writes waiting to be written to the disk.
BACnet Trend Log Map Descriptor Stats
Stat
Description
Total Record Count
Number of entries recorded.
Record Count
Current number of entries within the log, this will stop at the value
specified by the configuration.
Status Records Added
Number of status events.
Data Records Added
Number of data events.
Time Change Records
Added
Number of time change events.
SPL LED
The blue LED will flash periodically when an event log is stored to the disk, this light should not be on all
the time, otherwise we might be building up a back-log of outstanding writes.
Additional Information
BACnet MS/TP Driver Manual 39
7.4.2 Date and Time Synchronization
The FieldServer system time is not set on startup but depends on an external time synch to initialize its
clock. This can be done via BACnet time synch and should be done whenever comms to the device have
been down since this could indicate a restart. Since the time values are only correct after this synch it is
best for the BACnet Client to perform a time synch before enabling trend logging.
If the device is configured to start logging by itself from restart the initial timestamps will start at Jan 1, 1970,
and a time change record will be created on time synch.
NOTE: The FS-GUI can be used to set the system time if it connects to a FieldServer with an
uninitialized system time. To synchronize time in FS-GUI, click the System Time Synch
button on the bottom of the screen.
7.5 Writing to Custom Properties on Remote BACnet Devices
The Custom_Property and Tag_Type parameters allow the FieldServer to write to devices that
implemented custom properties that are not part of the BACnet protocol specification.
The following example writes to custom property 650 with Tag_Type 1, 9 and 4 (which are examples
vendor specific properties):
Map_Descriptors
Map_Descriptor_Name
, Node_Name
, Function
, Data_Array_Name
, Data_Array_Index
, Data_Type
MultistateWR
, BCU_12
, WRBX
, DA_MV
, 1
, MV
BinaryWR
, BCU_12
, WRBX
, DA_BV
, 1
, BV
FloatWR
, BCU_12
, WRBX
, DA_AV
, 1
, AV
, Object_ID
, Custom_Property
, Tag_Type
, Length
, 1
, 650
, 1
, 1
, 1
, 650
, 9
, 1
, 1
, 650
, 4
, 1
Additional Information
BACnet MS/TP Driver Manual 40
7.6 Intrinsic Reporting for Life Safety Point
To use Intrinsic Reporting for a LifeSafetyPoint, it is necessary to classify each of the states as Normal,
Alarm, Life-Safety Alarm or Trouble. This is done by adding another column to the Offset_Table, called
Table_User_Value.
Each state is then classified by inserting one of the following values in its row:
0 = normal
1 = alarm
2 = fault
3 = life-safety alarm
Offset_Table
Offset_Table_Name
, Table_String
, Table_Index_Value
, Table_User_Value
LSP_ALRM_TEXT
, SYSTEM READY
, 0
, 0
LSP_ALRM_TEXT
, PRE_ALARM
, 1
, 1
LSP_ALRM_TEXT
, ALARM!!!
, 2
, 1
LSP_ALRM_TEXT
, MAINTENANCE
, 3
, 2
LSP_ALRM_TEXT
, LIFE-SAFETY-ALARM1
, 4
, 3
LSP_ALRM_TEXT
, OFF-LINE
, 5
, 2
LSP_ALRM_TEXT
, IN SERVICE
, 6
, 0
LSP_ALRM_TEXT
, OTHER
, 7
, 1
LSP_ALRM_TEXT
, LIFE-SAFETY-ALARM2
, 8
, 3
LSP_ALRM_TEXT
, OFFLINE
, 9
, 2
LSP_ALRM_TEXT
, LIFE-SAFETY-ALARM3
, 10
, 3
Additional Information
BACnet MS/TP Driver Manual 41
8 Troubleshooting
8.1 Debugging a BACnet Connection
• If duplicate Object_Instances are configured in the FieldServer, the second call of the Instance
will overwrite the first one. This may cause a BACnet Object to be “lost.”
• If the Node Name configured on the BACnet Server Side of the configuration is not being
indicated as the Device Name on the BACnet SCADA system, then the FieldServer is not
communicating with the SCADA system. If the Device Object's name is being indicated, but the
Present_Value shows question marks, then it is likely that the Client Side of the FieldServer is not
communicating.
• Extra memory is required to store Map Descriptors that have the active/inactive text parameters
specified. If the defaults are appropriate, do not specify these parameters. This will save memory
and allow more Map Descriptors to be created.
• When a FieldServer/ProtoCessor is configured to support BACnet MS/TP virtual server nodes the
firmware achieves this by implementing a virtual router and thus a network number is required so
that it can expose its nodes to external devices as belonging to a specific network. (The default is
network 5 if not specified). This network number is defined on the bridge’s connection section as
Virtual_Network_Number. It must be unique for a site. Refer also to Section 7.1.2.
8.2 COV Configuration
• COV must be enabled if required for BACnet MS/TP. Refer to Section 7.2.1 for more information.
• COV only works for BACnet Map Descriptors with length set to 1. If length is not specified, then it
defaults to 1, so this is only a problem where length has been specified as greater than 1.
8.3 BACnet Specific Statistics
Stat
Description
Resolution
Link Control
A “who-is” link control message
was sent or received.
It is normal to receive a few link control
messages. If the number is higher than the
transmit/receive messages; however, there may
be a problem with lost communications.
Unsupported
Properties
A request for an unsupported
property was received.
This is not an error. BACnet clients often poll all
properties of a particular object to determine
which properties are supported.
Segmentation
Not Supported
Data was requested but the
response would have exceeded
the maximum size of the APDU
and could not be sent using an
un-segmented message.
This is not an error - the BACnet client will use a
different method to read data from the
FieldServer.
Sequence Error
Invoke ID of a reply did not
match the Invoke ID of the poll.
This message normally indicates a configuration
error.
Write Access
Denied
A write to an object was
denied.
This typically happens when trying to write to an
Input Object that is not Out-Of-Service. It is not
possible to write to Input Objects.
Exception
Errors
A BACnet Service was denied
because it is not supported.
Consult the PIC statement to determine what
services are supported.
Additional Information
BACnet MS/TP Driver Manual 42
8.4 BACnet Specific Error Messages
Message Description
Cause
Suggested Resolution
Bacnet DLL Temporarily
out of receive buffers
The FieldServer was flooded with more BACnet
packets than it could handle. This typically
occurs when a workstation discovers a large
network resulting in many Who-Is and I-Am
broadcasts. The FieldServer will recover, but
some timeout errors could result.
Take action only if the
error is continuous, in
which case the network
load must be analyzed
and corrected.
8.5 BACnet Error Response Decoding
BACnet reports errors in the following format:
T02> 10/22 02:57 HEXDUMP : ERROR_PDU
T02> 10/22 02:57 0x19d2d 50 97 0f 91 02 91 2a
T02> 10/22 02:57 BACnet -> Unexpected ERROR_PDU : err_class=2 err_code=42
These can be decoded using the tables below.
8.5.1 BACnet Error Class
Description
Value
Device
0
Object
1
Property
2
Resources
3
Security
4
Services
5
Additional Information
BACnet MS/TP Driver Manual 43
8.5.2 BACnet Error Codes for Error Class Object
Description
Value
Other
0
Authentication failed
1
Configuration in progress
2
Device busy
3
Dynamic creation not supported
4
File access denied
5
Incompatible security levels
6
Inconsistent parameters
7
Inconsistent selection criterion
8
Invalid data type
9
Invalid file access method
10
Invalid file start position
11
Invalid operator name
12
Invalid parameter data type
13
Invalid time stamp
14
Key generation error
15
Missing required parameter
16
No objects of specified type
17
No space for object
18
No space to add list element
19
No space to write property
20
Property is not a list
22
Object deletion not permitted
23
Object identifier already exists
24
Operational problem
25
Password failure
26
Read access denied
27
Security not supported
28
Service request denied
29
Timeout
30
Unknown object
31
Unknown property
32
Unknown vt class
34
Unknown vt session
35
Unsupported object type
36
Value out of range
37
Vt session already closed
38
Vt session termination failure
39
Write access denied
40
Character set not supported
41
Invalid array index
42
Invalid index
42
Additional Information
BACnet MS/TP Driver Manual 44
8.6 Rediscovering Offline Devices
The BACnet driver handles APDU retries internally and uses its own parameters, not the kernel parameters.
The kernel timeout and retry values should be left to default.
The following parameters can be configured on the Client Node:
• APDU_Timeout – default value is 10s
• APDU_Retries – default value is 3
The FieldServer will only send requests to the remote device once it has discovered it using the Who-Is / I-
Am process.
If a device does not respond and the APDU_Retries have been used up, the driver will revert to trying to
discover the device using Who-Is requests.
NOTE: There is also a background process of rediscovering devices independently of the polling
process. This occurs every 10 minutes.
8.7 Timeout Errors
NL TX Abort errors mean that the BACnet network layer was unable to transmit queued messages in time
and gave up on them. Outgoing packets are programmed with a 10 second timeout. If packets have not
been transmitted within this 10 second window, they are discarded and an error is recorded.
Timeout errors may be experienced on start-up if the network is not yet fully synchronized or if there are a
high number of nodes on the network. The FieldServer can only transmit the I-Ams a few at a time, and
only when it receives the MS/TP token.
It might help to give the MS/TP network some time to settle before attempting a discovery.
It may be advisable to discover the Nodes in a number of smaller Node ID ranges (say 10 at a time). The
Node_ID’s can be established from the configuration.
8.8 PDU Limit Reached Errors
A PDU limit reached error is returned when a device runs out of buffers for storing incoming or outgoing
messages (PDU = protocol data unit). A possible scenario is when a high number of server nodes is
configured and one or more global Who-Is requests is received. The FieldServer will then need to transmit
a response for each one, but if the MS/TP network is busy it might not get enough airtime to send them all
out. Another possibility is a buildup of unsent COV or Event Notifications.
Additional Information
BACnet MS/TP Driver Manual 45
9 Vendor Information
9.1 McQuay
McQuay Units are shipped with a default Device instance of the last 6 digits of the McQuay Serial number.
9.2 Liebert
Polling BACnet addresses that are not configured for Liebert systems may cause the connection to fail in
older versions of Liebert. Contact Liebert supplier for more information.
9.3 Automated Logic Corporation
When an ALC module is powered up, and it does not detect valid BACnet MS/TP traffic on its MS/TP port,
then the module goes into a terminal mode and MS/TP communications will not be initiated.
When connecting the FieldServer to an ALC BACnet MS/TP module, always start the FieldServer first. Wait
until the RUN Led is flashing on the FieldServer before powering up the MS/TP module.
9.4 Honeywell EBI
Honeywell EBI cannot process EventNotifications with ACK_Required set to 1. The ACK_Required property
of Notification Class Map Descriptors configured for use with EBI must therefore be set to 0.
9.5 Using Cimetrics Explorer
Cimetrics Explorer needs to be configured to use either BACnet Ethernet or BACnet/IP. This is not a setting
in the actual Cimetrics BACnet Explorer, but is done in the Cimetrics BACstac Protocol that can be found
in the Local Area Connection Properties as shown below:
Additional Information
BACnet MS/TP Driver Manual 46
Check the properties of this protocol to see what BACnet protocol is set on the Cimetrics Explorer.
To change the protocol, remove the current one and add a new one as shown below.
Additional Information
BACnet MS/TP Driver Manual 47
10 Reference
10.1 FieldServer Vendor ID
BACnet Vendor Name: Sierra Monitor Corporation
BACnet Vendor ID: 37
10.2 Object_Type Legal Values – Abbreviation Descriptions
Legal Value
Associated
BACnet
Number
Description
AI
0
ANALOG_INPUT
AO
1
ANALOG_OUTPUT
AV
2
ANALOG_VALUE
BI
3
BINARY_INPUT
BO
4
BINARY_OUTPUT
BV
5
BINARY_VALUE
MI
13
MULTI_STATE_INPUT
MO
14
MULTI_STATE_OUTPUT
MV
19
MULTI_STATE_VALUE
NC
15
NOTIFICATION_CLASS_OBJECT
LSP
21
LIFE_SAFETY_POINT
DEVICE
8
DEVICE
10.3 Configuring Binary Outputs
The BACnet specification defines the behavior of Binary Outputs such that the Present_Value property is
treated as a set-point and is only expected to change as a result of BACnet write requests from upstream,
and not as a result of values read from downstream. This may cause confusion in situations where a user
wants to map BACnet Binary Output objects to corresponding Binary Output points on a downstream
device, since the Present_Value property will not be updated to reflect the value of the downstream point.
Instead, the Feedback_Value property may be monitored in order to know the state of the downstream
point.
For alarms (EventNotifications) this implies that BACnet BO points will trigger a COMMAND_FAILURE
alarm, which will trigger if the Feedback_Value (read from the downstream) differs from the Present_Value.
In order to use the Present_Value property to read and write to a downstream binary output object, configure
a Binary Value object on the FieldServer.
Additional Information
BACnet MS/TP Driver Manual 48
10.4 Property Legal Values
Legal Value
Description
Object_Identifier
This property is a numeric code that is used to identify the object. It is unique within
the BACnet Device that maintains it.
Object_List
Relevant to Device Object Type. This property is a BACnetARRAY of
Object_Identifiers, one Object_Identifier for each object within the device that is
accessible through BACnet services. An Object_Identifier is composed of Object
Type and Object Instance and must be unique within a BACnet Device (for
example: Object Type = Analog Input, Object Instance = 3).
Present_Value
This property contains the present value of the Input / Output / Value
Object_Name
Character string providing the name of a BACnet object. The set of characters
used in the Object_Name is restricted to printable characters. The Object_Name
is determined by the Map_Descriptor_Name.
Description
Character string describing a BACnet object. This can be defined by the user to
give additional detail about the Object.
Out_of_Service
The Out_Of_Service property, of type BOOLEAN, is an indication whether (TRUE)
or not (FALSE) the physical input that the object represents is not in service. This
means that the Present_Value property is decoupled from the physical input and
will not track changes to the physical input when the value of Out_Of_Service is
TRUE. In addition, the Reliability property and the corresponding state of the
FAULT flag of the Status_Flags property shall be decoupled from the physical input
when Out_Of_Service is TRUE. While the Out_Of_Service property is TRUE, the
Present_Value and Reliability properties may be changed to any value as a means
of simulating specific fixed conditions or for testing purposes. Other functions that
depend on the state of the Present_Value or Reliability properties shall respond to
changes made to these properties while Out_Of_Service is TRUE, as if those
changes had occurred in the physical input.
Event_State
The Event_State property, of type BACnetEventState, is included in order to
provide a way to determine if this object has an active event state associated with
it. If the object supports intrinsic reporting, then the Event_State property shall
indicate the event state of the object. If the object does not support intrinsic
reporting, then the value of this property shall be NORMAL. Other values: FAULT,
OFF-NORMAL, HIGH-LIMIT, LOW-LIMIT, LIFE-SAFETY-ALARM.
Units
This property contains the units associated with the Present_Value property.
Reliability
The Reliability property, of type BACnetReliability, provides an indication of
whether the Present_Value or the operation of the physical input in question is
"reliable" as far as the BACnet Device or operator can determine and, if not, why.
The following values are supported:
NO_FAULT_DETECTED, UNRELIABLE_OTHER
Priority_Array
This property relates to Output and Value Object Types and is a read only array
that contains prioritized commands or NULLs in the order of decreasing priority.
The highest priority (lowest array index) with a non-NULL value is the active
command.
State_Text
Relevant to Multistate Object Types: This property is a BACnetARRAY of character
strings representing descriptions of all possible states of the Present_Value. The
number of descriptions matches the number of states defined in the
Number_Of_States property. The Present_Value, interpreted as an integer, serves
as an index into the array.
Number_Of_States
Relevant to Multistate Object Types: this property sets the total number of states
for which descriptions will be returned as defined under the State_Text property.
The number of states will be determined automatically by the largest state number
used when configuring the Offset Table. Refer to Section 7.1.6.
Additional Information
BACnet MS/TP Driver Manual 49
Legal Value
Description
Max_Master
Relevant to BACnet MS/TP Device Object Type: The Max_Master property, of type
Unsigned, shall be present if the device is a master node on an MS/TP network.
The value of Max_Master specifies the highest possible address for master nodes
and shall be less than or equal to 127. If the Max_Master property is not writeable
via BACnet services, its value shall be 127.
Max_Info_Frames
Relevant to BACnet MS/TP Device Object Type: The Max_Info_Frames property,
of type Unsigned, shall be present if the device is a node on an MS/TP network.
The value of Max_Info_Frames specifies the maximum number of information
frames the node may send before it must pass the token. If Max_Info_Frames is
not writable or otherwise user configurable, its value shall be 1.
Active_Text
Relevant to Binary Object Types: This property, of type CharacterString,
characterizes the intended effect of the ACTIVE state of the Present_Value
property from the human operator's viewpoint. The content of this string is a local
matter, but it is intended to represent a human-readable description of the ACTIVE
state. For example, if the physical input is a switch contact, then the Active_Text
property might be assigned a value such as "Fan 1 On".
Inactive_Text
This property, of type CharacterString, characterizes the intended effect of the
INACTIVE state of the Present_Value property from the human operator's
viewpoint. The content of this string is a local matter, but it is intended to represent
a human-readable description of the INACTIVE state. For example, if the physical
input is connected to a switch contact, then the Inactive_Text property might be
assigned a value such as "Fan 1 Off".
Description
A character string giving more information about the Object associated with the
Present_Value property.
Firmware_revision
The firmware revision of the application.
Relinquish_Default
This property is the default value to be used for the Present_Value property when
all command priority values in the Priority_Array property have a NULL value.
Event_Enable
The Event_Enable property is supported, but to save memory it is only instantiated
it if a point is configured for alarming, i.e. if it is set up with a reference to a
Notification Class Map Descriptor.
Min_Pres_Value
Specify the "Minimum Present Value" property.
Max_Pres_Value
Specify the "Maximum Present Value" property.
Mode
Operating Mode. Only 'ON' mode is supported.
Accepted_Modes
List of Operating Modes.
Silenced
Represents silenced state, but only "All Silenced" supported.
Operation_Expected
List of LifeSafety Operations, but only 'None' operation is supported.
Property_List
Returns the list of supported properties.
Additional Information
BACnet MS/TP Driver Manual 50
Legal Value
Description
Status_Flag
4 offsets of a data array will be used to contains four Boolean flags that indicate
the general health of the object. Three of the four flags are associated with the
values of other attributes within the same object. The four flags are as follows:
• In Alarm – The In Alarm flag is False (0) if the Event State property value is
Normal; otherwise, the In Alarm flag is True (1).
• Fault – Fault flag is True (1) if the Reliability attribute is not reliable; otherwise,
the Fault flag is False (0).
• Overridden – Overridden flag is Logical 1 if the Present Value is decoupled from
the hardware output because the Enabled attribute is False or the Out of Service
attribute is True; otherwise, the Overridden flag is Logical 0.
• Out of Service – Out of Service flag is True if the Out of Service attribute value is
True; otherwise, the Out of Service flag is False.
The following object types have a Status_Flags property:
• Analog Input, Analog Output, Analog Value
• Binary Input, Binary Output, Binary Value
• Multistate Input, Multistate Output, Multistate Value
• Trend Log
Additional Information
BACnet MS/TP Driver Manual 51
10.5 Supported BACnet Object Properties
Type
Supported Properties
Device Object
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
System_Status
Read
Vendor_Name
Read
Vendor_Identifier
Read
Model_Name
Read
Firmware_Revision
Read
Application_Software_Version
Optional
Location
Optional
Description
Read
Protocol_Version
Read
Protocol_Revision
Read
Protocol_Services_Supported
Read
Protocol_Object_Types_Supported
Read
Object_List
Read
Max_APDU_Length_Accepted
Read
Segmentation_Supported
Optional
Local_Time
Optional
Local_Date
Read
APDU_Timeout
Read
Number_Of_APDU_Retries
Optional
Max_Master
Optional
Max_Info_Frames
Read
Device_Address_Binding
Read
Database_Revision
Optional
Active_COV_Subscriptions
Read
Property_List
Analog Input
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Read
Units
Optional
COV_Increment
Optional
Notification_Class
Optional
High_Limit
Optional
Low_Limit
Optional
Deadband
Optional
Limit_Enable
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Analog Output
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Write
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Type
Supported Properties
Read
Units
Optional
Min_Pres_Value
Optional
Max_Pres_Value
Read
Priority_Array
Read
Relinquish_Default
Optional
COV_Increment
Optional
Time_Delay
Optional
Notification_Class
Optional
High_Limit
Optional
Low_Limit
Optional
Deadband
Optional
Limit_Enable
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Analog Value
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Read
Units
Optional
Priority_Array
Optional
Relinquish_Default
Optional
COV_Increment
Optional
Time_Delay
Optional
Notification_Class
Optional
High_Limit
Optional
Low_Limit
Optional
Deadband
Optional
Limit_Enable
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Optional
Min_Pres_Value
Optional
Max_Pres_Value
Read
Property_List
Binary Input
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Read
Polarity
Optional
Inactive_Text
Optional
Active_Text
Optional
Time_Delay
Optional
Notification_Class
Optional
Alarm_Value
Optional
Event_Enable
Additional Information
BACnet MS/TP Driver Manual 52
Type
Supported Properties
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Binary Output
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Write
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Read
Polarity
Optional
Inactive_Text
Optional
Active_Text
Read
Priority_Array
Read
Relinquish_Default
Optional
Time_Delay
Optional
Notification_Class
Optional
Feedback_Value
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Binary Value
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Optional
Inactive_Text
Optional
Active_Text
Optional
Priority_Array
Optional
Relinquish_Default
Optional
Time_Delay
Optional
Notification_Class
Optional
Alarm_Value
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Multi State Input
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Read
Number_Of_States
Optional
State_Text
Optional
Time_Delay
Optional
Notification_Class
Type
Supported Properties
Optional
Alarm_Values
Optional
Fault_Values
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Multi State Output
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Write
Present_Value
Optional
Description
Optional
Device_Type
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Read
Number_Of_States
Optional
State_Text
Read
Priority_Array
Read
Relinquish_Default
Optional
Time_Delay
Optional
Notification_Class
Optional
Feedback_Value
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Multi State Value
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Read
Number_Of_States
Optional
State_Text
Optional
Priority_Array
Optional
Relinquish_Default
Optional
Time_Delay
Optional
Notification_Class
Optional
Alarm_Values
Optional
Fault_Values
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Notification Class Object
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
Notification_Class
Read
Priority
Read
Ack_Required
Read
Recipient_List
Read
Property_List
Additional Information
BACnet MS/TP Driver Manual 53
Type
Supported Properties
Trend Log
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Optional
Description
Write
Enable
Optional
Log_Interval
Read
Stop_When_Full
Read
Buffer_Size
Read
Log_Buffer
Write
Record_Count
Read
Total_Record_Count
Read
Logging_Type
Read
Status_Flags
Optional
Notification_Threshold
Optional
Records_Since_Notification
Optional
Last_Notify_Record
Read
Event_State
Optional
Notification_Class
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Read
Property_List
Type
Supported Properties
Life Safety Point
Read
Object_Identifier
Write
Object_Name
Read
Object_Type
Read
Present_Value
Optional
Description
Read
Status_Flags
Read
Event_State
Optional
Reliability
Read
Out_Of_Service
Optional
Time_Delay
Optional
Notification_Class
Optional
Alarm_Values
Optional
Fault_Values
Optional
Event_Enable
Optional
Acked_Transitions
Optional
Notify_Type
Optional
Event_Time_Stamps
Write
Mode
Read
Accepted_Modes
Read
Silenced
Write
Operation_Expected
Read
Property_List
Additional Information
BACnet MS/TP Driver Manual 54
10.6 Units
Unit
Variation 1
Variation 2
Type
amperes
amps
A
Electrical
ampere-seconds
Energy
amperes-per-meter
Electrical
amperes-per-square-meter
Electrical
ampere-square-hours
Energy
ampere-square-meters
Electrical
bars
Pressure
becquerels
Other
btus
Energy
btus-per-hour
Power
btus-per-pound
Enthalpy
btus-per-pound-dry-air
Enthalpy
candelas
Light
candelas-per-square-meter
Light
centimeters
Length
centimeters-of-mercury
Pressure
centimeters-of-water
Pressure
cubic-feet
Volume
cubic-feet-per-day
Volumetric Flow
cubic-feet-per-hour
Volumetric Flow
cubic-feet-per-minute
Volumetric Flow
cubic-feet-per-second
Volumetric Flow
cubic-meters
Volume
cubic-meters-per-day
Volumetric Flow
cubic-meters-per-hour
Volumetric Flow
cubic-meters-per-minute
Volumetric Flow
cubic-meters-per-second
Volumetric Flow
currency1
Currency
currency10
Currency
currency2
Currency
currency3
Currency
currency4
Currency
currency5
Currency
currency6
Currency
currency7
Currency
currency8
Currency
currency9
Currency
cycles-per-hour
Frequency
cycles-per-minute
Frequency
days
Time
decibels
Electrical
decibels-a
Other
decibels-millivolt
Electrical
decibels-volt
Electrical
degree-days-Celsius
Temperature
degree-days-Fahrenheit
Temperature
degrees-angular
Other
degrees-Celsius
Deg-C
Deg_C
Temperature
degrees-Celsius-per-hour
Other
degrees-Celsius-per-minute
Other
degrees-Fahrenheit
Deg-F
Deg_F
Temperature
degrees-Fahrenheit-per-hour
Other
degrees-Fahrenheit-per-minute
Other
degrees-Kelvin
Deg-K
Deg_K
Temperature
degrees-Kelvin-per-hour
Temperature
degrees-Kelvin-per-minute
Temperature
degrees-phase
Electrical
delta-degrees-Fahrenheit
Temperature
delta-degrees-Kelvin
Temperature
farads
Electrical
feet
Length
feet-per-minute
Velocity
feet-per-second
Velocity
foot-candles
Light
Additional Information
BACnet MS/TP Driver Manual 55
Unit
Variation 1
Variation 2
Type
grams
Mass
grams-of-water-per-kilogram-dry-air
Humidity
grams-per-cubic-centimeter
Other
grams-per-cubic-meter
Other
grams-per-gram
Other
grams-per-kilogram
Other
grams-per-liter
Other
grams-per-milliliter
Other
grams-per-minute
Mass Flow
grams-per-second
Mass Flow
grams-per-square-meter
Other
gray
Other
hectopascals
Pressure
henrys
Electrical
hertz
Hz
Frequency
horsepower
HP
Power
hours
Time
hundredths-seconds
Time
imperial-gallons
Volume
imperial-gallons-per-minute
Volumetric Flow
inches
Length
inches-of-mercury
Pressure
inches-of-water
Pressure
joule-per-hours
Power
joules
Energy
joule-seconds
Other
joules-per-cubic-meter
Other
joules-per-degree-Kelvin
Entropy
joules-per-kilogram-degree-Kelvin
Entropy
joules-per-kilogram-dry-air
Enthalpy
kilobecquerels
Other
kilo-btus
Energy
kilo-btus-per-hour
Power
kilograms
kg
Mass
kilograms-per-cubic-meter
Other
kilograms-per-hour
Mass Flow
kilograms-per-kilogram
Other
kilograms-per-minute
Mass Flow
kilograms-per-second
Mass Flow
kilohertz
kHz
Frequency
kilohms
Electrical
kilojoules
Energy
kilojoules-per-degree-Kelvin
Entropy
kilojoules-per-kilogram
Energy
kilojoules-per-kilogram-dry-air
Enthalpy
kilometers
Length
kilometers-per-hour
Velocity
kilopascals
Kpa
Pressure
kilovolt-ampere-hours
Energy
kilovolt-ampere-hours-reactive
Energy
kilovolt-amperes
kilovolt-amps
KVA
Electrical
kilovolt-amperes-reactive
KVAR
Electrical
kilovolts
Electrical
kilowatt-hours
kWh
Energy
kilowatt-hours-per-square-foot
Other
kilowatt-hours-per-square-meter
Other
kilowatt-hours-reactive
Energy
kilowatts
kW
Power
liters
Volume
liters-per-hour
Volumetric Flow
liters-per-minute
Volumetric Flow
liters-per-second
Volumetric Flow
lumens
Light
luxes
Light
megabecquerels
Other
Additional Information
BACnet MS/TP Driver Manual 56
Unit
Variation 1
Variation 2
Type
mega-btus
Energy
megahertz
MHz
Frequency
megajoules
Energy
megajoules-per-degree-Kelvin
Entropy
megajoules-per-kilogram-dry-air
Enthalpy
megajoules-per-square-foot
Other
megajoules-per-square-meter
Other
megavolt-ampere-hours
Energy
megavolt-ampere-hours-reactive
Energy
megavolt-amperes
megavolt-amps
Electrical
megavolt-amperes-reactive
MVAR
Electrical
megavolts
Electrical
megawatt-hours
MWh
Energy
megawatt-hours-reactive
Energy
megawatts
MW
Power
megohms
Electrical
meters
Length
meters-per-hour
Velocity
meters-per-minute
Velocity
meters-per-second
Velocity
meters-per-second-per-second
Acceleration
micrograms-per-cubic-meter
Other
micrograms-per-liter
Other
microgray
Other
micrometers
Length
microsiemens
Electrical
microsieverts
Other
microsieverts-per-hour
Other
miles-per-hour
Velocity
milliamperes
milliamps
Electrical
millibars
Pressure
milligrams
Mass
milligrams-per-cubic-meter
Other
milligrams-per-gram
Other
milligrams-per-kilogram
Other
milligrams-per-liter
Other
milligray
Other
milliliters
Volume
milliliters-per-second
Volumetric Flow
millimeters
Length
millimeters-of-mercury
Pressure
millimeters-of-water
Pressure
millimeters-per-minute
Velocity
millimeters-per-second
Velocity
milliohms
Electrical
million-standard-cubic-feet-per-day
Volumetric Flow
million-standard-cubic-feet-per-minute
Volumetric Flow
millirems
Other
millirems-per-hour
Other
milliseconds
Time
millisiemens
Electrical
millisieverts
Other
millivolts
Electrical
milliwatts
Power
minutes
Time
minutes-per-degree-kelvin
Other
mole-percent
Other
months
Time
nanograms-per-cubic-meter
Other
nephelometric-turbidity-unit
Other
newton
Force
newton-meters
Torque
newton-seconds
Other
newtons-per-meter
Other
no-units
No_Units
None
Other
Additional Information
BACnet MS/TP Driver Manual 57
Unit
Variation 1
Variation 2
Type
ohm-meters
Electrical
ohm-meter-squared-per-meter
Electrical
ohms
Electrical
parts-per-billion
Other
parts-per-million
Other
pascals
Pressure
pascal-seconds
Other
percent
Other
percent-obscuration-per-foot
Other
percent-obscuration-per-meter
Other
percent-per-second
Other
percent-relative-humidity
% RH; %RH
Percent RH; Percent RH
Humidity
per-hour
Frequency
per-mille
Other
per-minute
Other
per-second
Other
pH
Other
pounds-force-per-square-inch
PSI
pounds-force-per-sq-inch
Pressure
pounds-mass
Mass
pounds-mass-per-day
Volumetric Flow
pounds-mass-per-hour
Mass Flow
pounds-mass-per-minute
Mass Flow
pounds-mass-per-second
Mass Flow
power-factor
PF
Electrical
psi-per-degree-Fahrenheit
Other
radians
Other
radians-per-second
Other
revolutions-per-minute
Other
seconds
Secs
S
Time
siemens
Electrical
siemens-per-meter
Electrical
sieverts
Other
square-centimeters
Area
square-feet
Area
square-inches
Area
square-meters
Area
square-meters-per-Newton
Other
standard-cubic-feet-per-day
Volumetric Flow
teslas
Electrical
therms
Energy
thousand-cubic-feet-per-day
Volumetric Flow
thousand-standard-cubic-feet-per-day
Volumetric Flow
ton-hours
Energy
tons
Mass
tons-per-hour
Mass Flow
tons-refrigeration
Power
us-gallons
Gallons
Volume
us-gallons-per-hour
Volumetric Flow
us-gallons-per-minute
GPM
Volumetric Flow
volt-ampere-hours
Energy
volt-ampere-hours-reactive
Energy
volt-amperes
Volt-Amps
VA
Electrical
volt-amperes-reactive
VAR
Electrical
volts
voltage
Electrical
volts-per-degree-Kelvin
Electrical
volts-per-meter
Electrical
volt-square-hours
Energy
watt-hours
wH
Energy
watt-hours-per-cubic-meter
Other
watt-hours-reactive
Energy
watts
W
Power
watts-per-meter-per-degree-Kelvin
Other
watts-per-square-foot
Light
watts-per-square-meter
Light
watts-per-square-meter-degree-kelvin
Other
Additional Information
BACnet MS/TP Driver Manual 58
Unit
Variation 1
Variation 2
Type
webers
Electrical
weeks
Time
years
Time
