Modbus to BACnet converter

DIGIKEY P#. 4008-TM171ARS485-ND I would like to know if this will work for a fan controller speaking Modbus to the building management system using BACnet.

Goal is to connect the modbus controller with this converter so they have access to control fans speed, on time, and the like.

Thank you,
Scott Guinee

Hello Scott,

Welcome to the DigiKey forum.

My intuition says that the TM171ARS485 communications module would allow your Schneider Electric Modicon M171 or M172 nano PLC to interface with the Building Automation and Control Network (BACnet).

A good deal of programming / system integration is required to:

  • establish comms between the greater network and the nano PLC via the new comms module

  • program the primary control workstation plus related BACnet devices such as wall mounted control switches

  • program the PLC module to monitor and control the fan

May I recommend you start with the Modicon PLC configurator as shown below. Please use the tool to verify the communications module is compatible with your chosen PLC.

Unfortunately, I can offer no further assistance, as I have yet to program in the BACnet environment. While I do have a TM221 PLC in my hands, that will not help you today.

Perhaps other readers of this post can offer additional assistance or insights.

Best Wishes,


P.S. You may find additional assistance in Schneider’s learning community. Again, my apologies for not being able to directly answer your question.