Dear all

I've success build project Modbus RTU with S7 1200 and CM1241 in TIA v13 before. Now, I make a new project with new firmware and TIA v15 update 2. But it doesn't work. My configuration list here:

- CPU1214C DC/DC/Rly 6ES7 214-1HG40-0XB0 v4.2 as Modbus RTU Master.

- CM1241 RS485 6ES7 241-1CH32-0XB0 v2.2.

- TIA v15 update 2.

- Instruction MODBUS RTU v4.2 with Modbus_Comm_Load v3.1 and Modbus_Master v3.1.

- Modbus RTU RS485 half duplex, 9600bps, None pairity, 1 stop bit

After Modbus_Comm_Load done, CPU begin transmission data to Modbus Slave. But I've try to use some Modbus Slave (Power meter, Remote io) but can't see any data return. Modbus Master Status word value is 7000h or 7002h, only Tx blink.

And finally, I use Modbus Slave Simulator software + USB2RS485 converter to test, COM port on my PC didn't receive any data request. I connect pin 3 + pin 8 on DB-9 port and also tried to swap.

Any help

Tks&Brs

Hi,

Do you Resolve problem?

The best regards

Jaca

I don't know maybe try in Modbus_Comm_Load use in REQ firstscan and insert MOVE block in network 1 with value 4 to operand Modbus_Comm_Load >> MODE maybe re write will help .if this not help try remove Modbus_Comm_Load and Modbus_Master block's and put MB_COMM_LOAD and MB_MASTER.

But if you tell what tx flashing then it try to send but not get response so one more option i think you need in Modbus Master block remove REQ bit Clock0.5Hz, you need put REQ bit then you get response or after timeout maybe 1s. Now your request 0.5HZ maybe to fast for transmit and get response

Also see status or it's busy