[nguyenthanhcanh]

Hi Vitor,

You can communication with 3G3MV inveter by modbus protocol from host link port or peripheral port via RS422/485 (of course you need a converter to convert you PLC port).

You can use TXD, RXD instructions with ladder program.

or CX-protocol and Protocol macro (PMCR) function. In this case, you need CQM1H-SCB41 (for CQM1H-CPU51/61) or CJ1W-SCU21/41 (for CJ1).

Concerned manuals:

1. CQM1H Programming Manual + CQM1H serial communication board
2. CJ1/CS1 Programming Manual + CJ1/CS1 Instruction References
3. 3G3MV Manual (see Chapter 7 for communication)
4. CX-protocol software + CX-protocol manual (if use protocol macro function)

[Vitor]

I tried but without success. I did not communicate in none of the directions.
Can you send a simple example (ex to control freq ref)...

Thanks.

[Nibroc]

Hi,

Have a look at the attached Modbus Master ladder program. (I have not used it but it looks OK) This code is a general purpose? modbus master for the CPM2A, it will suit a CQM1/CJ1 with little modification.

If you are not experienced with PLC programming or serial comms, it would be easier to use CJ1W-SCUxx card with protocol macros.

To write Modbus in Ladder code you will need an understanding of the Modbus protocol + the method to generate the CRC checksums required - this can take some time to learn the first time!!

To assist with development, you can use a terminal program such as hyperterminal (or Omron Multiway which will generate the CRC checksum for you). You can then monitor the strings output from the PLC, and test the VSD to veiw the reply etc.

Attached File(s)

•  CPM2C_Modbus_Master.zip (116K)
  Number of downloads: 149

[Jay Anthony]

After you download the above program, be sure to download the DM file. Most people forget to download this file also. It will be used to calculate the CRC.