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Bytes Missing Error
Trying to communicate with AB Micrologix 1500 on Channel 1 via Modbus. I can communicate over hard wire connection directly to PLC via PC with Modbus Poll software, but whenever I connect fiber converters I get bytes missing error.

I used the Phoenix PSM RS232/FO converter before between a Moore DCS and Delta V and it worked flawlessly. Now I am trying to communicate same way between a Moore APACS DCS and an AB Micrologix 1500 PLC. All I get are checksum errors on Moore DCS and Bytes Missing error with a MODPoll software. Anyone have a clue what might be going on?