In a G3 station, BACnet Device Manager, not able to Discover any MSTP devices.

Issue

In a G3 station, BACnet Device Manager, not able to Discover any MSTP devices.

Product Line

TAC I/A Series

Environment

ENC with a BACnet MS\TP trunk under it, all revisions

Cause

There are multiple settings that must be made before BACnet communications will be enabled on the MS/TP trunk.

Resolution

1. The Object Id of the BACnet Local device must be set to a value other than -1.

2. The BACnet Network must have the Enable flag set = true

3. The MSTP port itself must be enabled. Right-click on the MstpPort in the tree, select Actions / Enable.

4. Verify that the MSTP port Enabled flag is "true", and the port is enabled.

5. Verify that the Port Name (COM3 in this example) is an active RS-485 port on the ENC.

6. Verify that the Baud Rate (19,200 in this example) matches the baud rate of the MSTP controllers. In the case of MNB- series controllers, the network baud rate is established by the WorkPlace Tech Commissioning Tool.

7. Remember that the MSTP Network number must be unique on the BACnet internetwork.  In this case, the MSTP network number  = 7966, which is not a likely default value, so minimizes the possibility of being duplicated by another vendor.