I am having difficulty making a Modbus RTU communication with Getway Modbus that communicates in RS 485, the Getway is connected to a CM Ptp 2.0 Card that is installed in a remote ET200SP of a PLC CPU 416F. The programming software is Simatic manager v5.6. I am using the following documents as a reference:

https://cache.industry.siemens.com/dl/files/272/109755272/att_940616/v1/STEP7_V1x_MODBUS_RTU.pdf

https://support.industry.siemens.com/cs/ww/de/view/69124220

It is showing error 8280 but I don't know if there are other things wrong, in the document it is port configuration but I didn't identify any errors in the project.

I also have a question: is it really necessary to restart the CPU or execute the REQ only once and it answers, I can't turn off the PLC from the process