Modbus-RTU on CP1L with Inverter 3G3MX2

[thaiecoautomation 1]

Hi There, this Forum useful for me! But, I got some proble on Modbus communication, I'm using OMRON CP1L + CP1W-CIF11 (RS485) to communicate with three Inverters model 3G3MX2. After i am read through the forum and i managed to found a "Sample code" uploaded by PMCR (Sparky) and this is a "PERFECT CODE" to me I follow this link : Link I am try to write the data to holding register number 0002h (Output Frequency Setting LOW) on node 1, node 2 not find any problem, but when try to write on node 3 found problem (FFFF) ! What happen? How to correct it ?? Anyone have this problem like this, problem from Inverter, plc or wiring ? Best. CP1L.pdf CP1LCP1HCJ1CJ2CS1ModbusSolutionV211.pdf

[PMCR 66]

It appears to me as though your data is correct in the D6xxx area, so I suspect wiring or inverter setup. Is any Modbus communications (reads?) working to MX2 # 3? I would double check the following parameters.A001 = 03. Set Modbus as Frequency Reference Input A002 = 03. Set Modbus as the Run/ Stop command reference C071 = 06. Set 19,200 as the baud rate (or whatever baud rate you are using) C072 = 03. Set the Modbus node to 03 C074 = 00. Set the Parity to None C075 = 00. Set the Stop Bits to 1 C076 = 02. Ignore Communications Errors (Change per application). C077 = 00. Communications Timeout How far apart are inverters from the PLC (how long is the RS485 wire)? Do you have the terminator on the far end of the wire? (away from the CP1L)?

[thaiecoautomation 1]

Thanks PMCR, i will be double check as your recomment. About the distance from CL1L to the end just 2 m (I installed all of the control cabinet.) and terminating resistor are on both end.

[PMCR 66]

Any update on your progress for the rest of the readers?

[thaiecoautomation 1]

After i am double check no any problem from the program and setting, then i decided send it back to supplier to check it. And supplier can't repair, they told me you program correct, problem might be from the inverter. And after that the omron head office in Thailand send my inverter back to Japan to chack and repair. Thanks so much ^^