Configuring a network with an MS/TP port

A remote station, which runs on a QNX-based controller is the only device that supports a BACnet MS/TP port.
Prerequisites: You are working in Workbench running on a PC. You have added an MX/TP port to the BacnetCom > Network node in a controller station.
  1. Expand Config > Drivers > BacnetNetwork > Bacnet Comm > Network and double-click MstpPort in the Nav tree.
  2. Set the Network Number from -1 to the BACnet network number for the network segment to which you are connecting and click Save.
    • If this is an existing BACnet installation, make sure to use the same network number that is already in use.
    • If this is a new BACnet installation, configure this number as needed.
  3. Double-click the Link component in the property sheet.
  4. Set the Port Name to RS-485.
    The station can have a total of three RS-485 ports:
    • Set the Port Name to COM3 with a regular option card.
    • Set thePort Name to COM3, COM4 or COM5 with a dual-RS-485 option card.
  5. Do one of the following:
    • Leave the Mstp Address at 0 (the default), and verify that no other MS/TP device has a same address.
    • Set the Mstp Address to a unique BACnet MAC address on the MSTP trunk.
    The valid range is from 0 (default) to 127 decimal. Each BACnet device on the MS/TP network segment must have a unique MAC address. If there is ever a lost token, the device with the lowest MAC address regenerates the token (in this case it will be the station).
  6. Set the Max Master to the highest known master device on the network with possible room for expansion.
  7. Set the Max Info Frames to the range from 0 to 100.
    This property controls how many messages are sent before passing the token. In some cases, increasing this value up to 50 may improve performance.
  8. To save the MstpPort changes, click Save.
  9. Right-click the MstpPort (in property sheet or Nav side bar), and select Actions > Enable.
    The Status property under MstpPort should report {ok}.