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hello, I want to read data via ModBus from a Siemens PLC that works as Slave and then I want to be able to read that data from any device wirelessly connected to the rut240, is this possible?

Thanks in advance

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Hi,

Currently, device functionalities do not support the ability for the user to view Modbus data in such a manner. However, as an alternative, you can use Data to server (HTTP(S) or MQTT) or MQTT Gateway functionalities to upload data to a server or send data via MQTT broker respectively.

More information about Data to server functionality can be found HERE,

and information about MQTT Gateway HERE.

For the Data to the server to work, you will have to have a server configured to accept, process, and present Modbus data to users. This can be either an external, publicly available server or a LAN device with a configured TCP server (A device connected via WiFI and running a TCP server application in this case). Any TCP server application can be used to receive Modbus data. For example, Hercules TCP Server.

On the other hand, a third-party MQTT broker, such as flespi, can be used when using MQTT as a Gateway. In this implementation, RUT240 acts as an MQTT publisher, and flespi (or any other MQTT broker) acts as an MQTT broker. A device, for example, a PC can be configured as an MQTT subscriber. Publisher (RUT240) pushes Modbus data to a broker (flespi), and the subscriber (PC) can obtain that data from a broker. 

A Wiki page on how to configure a Modbus TCP Master and MQTT Gateway can be found HERE.

Another option is to configure port forwarding. How this works:

  • Configure the port forwarding rule to forward data received on port 502 (Modbus default port) to a specific device on LAN (the device can be connected via WiFi to RUT240 and be on the same LAN).
  • Configure Modbus TCP Master in Services-> Modbus -> Modbus TCP Master. More information HERE and HERE.
  • RUT240 will receive Modbus data on port 502 and forward this data to a specified IP address in LAN.

More information about port forwarding can be found HERE and HERE.

Technically, the data is sent to a device wirelessly connected to RUT240. However, The device, to which data is being sent has to accept this data and present it to the user somehow. This can be some TCP client. If you do not mind how the data is represented, an application such as Hercules TCP client can be used. 

Kind Regards,

Andzej