Siemens s71200 modbus tcp communication

Hello everyone, i am new to the Teltonika arena…

I am trying to read data from siemens plc using RUT230 via Modbus tcp. i have done all the setup following the tech notes online but

now problem i have is after setting up the data requests…when I press the test button on web ui , i do not get any value.

Also i wanted to ask about the addressing, do we use the normal 40001 for holding registers or there are special registers that i need to use.

Hello,

Apologies for a late reply.

Would it be possible for you to share the message that you get when you try to read Modbus data via ‘test’ button?

There is no need to enter full registers. It should be enough to set the correct function (for example, read holding register), and enter the register number that you you want to obtain. For example, register number 2 (which is Register Address 1). The RutOS uses register numbers instead of addresses. The difference is that addresses start at 0, while numbers start at 1. Basically, if your device uses registers, simply add 1 to get a register number and use it in the modbus client configurations.

Kind Regards,

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