Filter
Top Products
FS-8700-73 BACnet MSTP Driver Manual Page 21 of 24
FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web: www.fieldserver.com
Tel: (408) 262-2299 Fax: (408) 262-9042 Toll Free: (888) 509-1970 email: support@fieldserver.com
Appendix C.2. 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.
You should not see this message. It
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
This may be a problem on the Client
system. Consult the PIC statement to
determine what services are supported.
Appendix A.1. Network Number
If there are multiple FieldServers or third party devices on a BACnet Network each with multiple
Server nodes a unique network number must be assigned to each device. This will ensure
communication between the BACnet Client and all Servers.
For MSTP devices the network number is provided by the router.
A consequence of this is that when you configure a MSTP client you must know not only the Node_ID
of the server node but you need to know the network number. These are specified on the node
descriptor for client applications as Node_ID and Network_Number. If the network number is not
specified then the node is assumed to exist on the local segment.
Another consequence of this is that the network number is not relevant for server configurations.
The network number is a 16 bit positive number. To override the FieldServer’s default network
number 5, refer to Section 5.1
Appendix C.3. Known problems with third party devices - Automated Logic
Corporation.
When an ALC module is powered up, and it does not detect valid BACnet/MSTP traffic on its MSTP
port, then the module goes into a terminal mode and MSTP communications will never happen.
When connecting the FieldServer to an ALC BACnet/MSTP module, always start the FieldServer first.
Wait until the RUN Led is flashing on the FieldServer before powering up the MSTP module.