Grayhill Radio Modems


Thread Starter


Does anyone have experence using Modicon controllers and Grayhill Modbus radio modems? I am looking for the following information:

1) Correct cable from Momemtum to Modem
2) Correct cable from Compact E275 to Modem
3) Preferred Mode of Operation (Speed etc...)
4) Correct settings for the XMIT block in the
Momentum to read registers from the Compact.

Current Issue - Radio modems check out as communicating ok. I use the XMIT block to read a single register, but it times out with error 116 (Modbus response message time-out). If you watch the Modbus port, it is active and communicating until timeout is reached. Looking for ideas.

Bob Peterson

IIRC, if the Modbus light is blinking it means that a valid Modbus message was received. It does not necessarily mean the the attached slave device will do anything.

If you are unable to communicate with the slave device, it may mean you are talking to the wrong Modbus address.

Bob Peterson