Reading values from Siemens PLC using TCP

[somapa]

Hi,

I bought Unipi Neuron with a vision of reading Siemens PLC memory and creating web based HMIs for those data. Is it even possible? Can someone point me to some tutorial because there aren´t any texts on how to do that. I am currently using Mervis OS but I cannot find a way to read S7-300 addresses.

Thank you.

[Martin Kudláček]

Hello @somapa,
the first thing is to configure the Siemens PLC as the ModbusTCP slave. Unfortunately we don't have any direct experience with it, so you have to look for help somewhere else. But you can verify the settings with e.g. qModMaster.

The second step is to configure generic Modbus slave device in Mervis and we have a tutorial for that: https://kb.unipi.technology/en:sw:01-mervis:connecting-to-modbus-slave-device-hidden

If, in any case, you wouldn't be able to set the Siemens as ModbusTCP slave, you can set the Mervis as ModbusTCP slave and let the Siemens update the registers. You can read more about how to set the Mervis as ModbusTCP slave here: https://kb.unipi.technology/en:sw:01-mervis:setting-modbus-server-hidden

Best regards,
Martin