hi kijo 

i'm have same problem 

kindly advise how to solve this 

thanks

chee

kijo

Hi to all,

according to example programs on forum I made program for Modbus communication for slave S1200 (6ES7 214-1AG40-0XB0) and communication board CB1241 (6ES7 241-1CH30-1XB0) using TIA (Version V13 SP1 Update 9).

In order to test communication I used second  PLC as Master, and everything WORKED well. (parts of program for MODBUS communication can be found in attachment)

Now, I want to test communication additionally with Modbus poll software on PLC. I am using Moxa 1150 with DB9 connector to connect PLC with PC. (wiring can be found in attachment)

Settings of Modbus poll software can be found in attachment.

When I use function code 03, TxD and RxD on Moxa connector are blinking, but only RxD is blinking on CM1241, and I receive error "Checksum error" when trying to write on only one address. Or "Insufficient bytes received" when trying to read from more then one address.

When I use function code 06(write single register) I don't have errors but I don't receive anything on PLC.

Also, I tried to change in Modbus poll to PLC address(base1) but received same errors.

Can you please give me some advice? If anything else is needed let me know so I will post it later.

Regards