I/A Series G3 Modbus TCP communications to Siemens Moore 353 controller stops updating after a period of time after ENC/JACE reboot or station start.

Issue

I/A Series G3 Modbus TCP communications to Siemens Moore 353 controller stops updating after a period of time after ENC/JACE reboot or station start.  The controllers do not drop offline and the associated Modbus proxy points no longer appear to update.

Product Line

TAC I/A Series

Environment

I/A Series G3, Modbus TCP 3.6.47 and lower

Cause

Modbus TCP transaction Identifiers are used to associate the future response with the request.  The transaction ID is a two byte value that can range between 0 and 65535. The Siemens Moore 353 controller appears unable to process Modbus transaction IDs at or higher than 1024.

Resolution

The I/A Series G3 Modbus TCP driver has been modified to allow the configuring of the maximum transaction ID for each device.

  1. Download the following modules from The Exchange Download Center:
  2. Install to the appropriate I/A Series G3 Workbench modules folder and upgrade the modules in the ENC/JACE.
  3. Modify the transaction ID to a value lower than 1024 and reboot the ENC/JACE station.