GE fanuc 90-30 series modbus RTU communication

Dear Sir,
I have GE Fanuc PLC CPU350 and CMM311 module.
1. CMM module configured as RTU only
2. Connected CMM module(Pins 2, 3, 7) to PC usng RS232 to USB converter.
3. Modscan software is using to read the PLC register.

Problem:
1. On CMM US1 led is blinking but modscan showing timeout.
2. Is there any configuration/Program required??

Thanks in Advance

The Data Rate, Flow Control, Parity and Station Address settings for the port in the PLC's hardware configuration must match your settings in Modscan. The blinking LED on the CMM311 module indicates traffic on the cable. The lack of a response in Modscan suggests a mismatch in one or more of the parameters.