Attempts to connect to an MR-VAV-AX and make a change has no effect.

Issue

Attempts to connect to an MR-VAV-AX and make a change has no effect.

Looking at the MCU Configuration, the address shows to be communicating, but the Communications show a lot of bad CRCs or No Reply. 

Product Line

TAC I/NET

Environment

I/NET site

Cause

Variety of causes, check below to troubleshoot.

Resolution

There are a couple of things that you need to look at:

  1. Verify that the controller has a proper power supply and it is grounded properly.
  2. Verify that it is communicating to the MRI properly and there are no shorts or anything on the Sub-LAN wire.
  3. After checking these, go back to the MCU Configuration and look at the comm. Stats again, if these are still showing bad CRC’s or No Reply then the unit (MR-VAV) itself may be bad and would have to be replaced.