Hello Mr Denilson Pegaia.

Thank you for your topic. 

I has a question hope that you can explain to me. i have one S7 1500 PLC (192.168.7.121) and E+H modbus device (192.168.7.151), i want to read value "Holding Register"  from modbus device to PLC but it is not work eventhough i try to fix all necessary infor following example. PC can see value in modbus device via ModScan solf ware. i use port 502. i attached a picture show what i did.

Much appriciate for your help. 

Thank you.

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Split from Sample Program: Modbus TCP with S7-1500.

Hi,

I suggest you the follow changes test:

1 - connect EN directly to power (no contacts)

2 - connect EN to 1s clock memory + (it is important) a edge detection (e.g. |P| contact)

Thanks all your information.

A problem was sloved.  We go to instance DB and change "MB_Unit_ID" from value default FF to 1 (as ID) then all thing can read.

Many thanks agian.