I've made a simple program to communicate with a Modbus Slave. I read 4 registers(with diferend data lenght's from the PLC that act's like a Modbus slave.

I first execute the 4 COMM_Load blocks (at startup, one at a time) and then when I try to read the first register of bool variables (or any other, one at a time), the busy output is ON and a while later the error bit is ON and the error is 8070. It's not described in the manual what this error ID is so, do any of you perhaps know what it. Also please tell me if I have the correct sequence of blocks.

It's strange to me that If I only work with one Comm_Load and Master block the comunication works.

Thanks in advanced.

Best regards.

Aleix

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New subject after splitting from S7 1200 modbus sample program required