Hi All,

Attached show the PLC S7-1500 CPU with profinet slave module.

CM PtP RS422/485 was configured at slave module.

mine comm_load function cannot done, i tried create a new and simple program as per attached but i have no luck.

please help to check which parameter i missed.

Mode=4 (RS485 2 wire halft duplex mode) already set as start value.

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Split from Modbus RTU Negative Aknowledge.