EN2MB-R Modbus TCP - Reading OK, Writing Stale Values

Anybus Support Anybus Gateways
#1

We’ve had an HMS-EN2MB-R module in operation for 2 years without issue, working with a CompactLogix PLC. This communicates over modbus to RIO. We have noticed the data written to the RIO is not updating correctly recently. When we check the transaction manager, the data is not reflective of what is in the PLC output registers. The input data is working fine but the output data is not.
There are no errors in the ethernet statistics in the configuration manager and no hardware has been changed. The anybus module has been powercycled but it’s still writing the same stale values to our RIO.
I have swapped the RIO module and written to the RIO module with other software to prove the RIO module is okay. I have swapped the EN2MB-R with a spare unit and we are getting the same results. We have not powercycled our PLC yet as there is essential equipment we can’t shut down.

Any thoughts on what could be happening?

#2

Just some follow-up information for clarity:

  • Action on no Network1 IO is set to Clear for all outputs.
  • Not using the control word.
  • 500ms scan time/5000ms timeout. This is over a somewhat weak 3g connection.
  • Lights for Network 1 and 2 are green and no errors on the Anybus. Tried both ports for each network.

Writing modbus to the RIO base with other software gets overwritten by the Anybus, so we can confirm it’s writing.

#3

Hi @zwisyn,

Can you send me the config file and a screenshot of the Transaction Monitor page? Also, screenshots to show the data in the PLC at that time would be helpful.

Are the LEDs flashing green or solid green?

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#4

Hello! We found the issue. Our PLC task was set to Disable Automatic Output Processing To Reduce Task Overhead. After disabling this our device is working again.

#5

Great! Thank you for the update. I’m glad you were able to get it working!