I have an Unitronics V570 PLC which takes temperature readings. An Ethernet card enabled PLC is really expensive so I plan to connect the PLC to a Raspeberry PI. How can I use Python functions that allow the computer to connect to web pages. I will eventually build a web site with PHP that will accept a connection from the Raspberry Pi. I will then let the web page load the data into a MySQL database and operators can view this data online.

My question is: How can I connect the raspberry Pi to the PLC to extract all the data I would need to send to the web page. The Rpi has a serial port built into its GPIO connector and I have built an interface that would allow serial connection between the Rpi and the PLC. How can I establish connections between the Rpi and the PLC? I will be using RS232 communications from the PLC to Rpi

1 Answer 1


For RS232 your looking for power, Txd and Rxd (pin 8 and 10)


These are all included in the GPIO

you can use this python side to read and write


You may need to adjust the power lines

once the data is in python you can save it or re send it to another database.

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