1

Would anyone have any recommendations for a modbus newbie on getting a pi to talk to a communicating sensor?

2 options

Option 1, $10: https://www.amazon.com/Serial-Converter-Adapter-interface-FT232RL/dp/B01MYSQLF0

And these steps https://medium.com/@boonsanti/raspberry-pi-3-model-b-modbus-rs-485-to-modbus-tcp-ip-gateway-9ed14ce2c08e

OR this pihat option 2, $40: https://www.instructables.com/id/How-to-Use-Modbus-With-Raspberry-Pi/

Option 2 seems like it even has a package to install in the directions called minimal modbus. Any idea if that would be utilized on both options? If one option seems easier for a beginner that's what I'll choose!

Temp and humidity sensor test trial if I can get it to work I'm hoping for a modbus electrical sub meter:)

https://www.amazon.com/Display-Temperature-Humidity-Sensor-External/dp/B078PHLR4T

Thanks for any help/tips!

2

That depends what you want I guess. The second option includes a galvanic isolation which makes it safer (both in terms of signal interference and personal safety) in more industrial environment and it also has more features in general. But because you want to use it to communicate with a rather simple sensor the USB to RS485 should be enough. MinimalModbus is just a python library so that should work with either of your hardware options.

4
  • Hi the idea if I can get Modbus to work would be in an industrial application... Submetering electrical energy with one of these on a large motor.. powermeterstore.com/p8161/acuvim_kl.php
    – HenryHub
    Jun 15 '20 at 15:56
  • So the pi hat option would be better route to go? Do the steps on the indestructible site seem legit and then I think i would just use minimal modbus to poll for the electrical meter device & energy value
    – HenryHub
    Jun 15 '20 at 15:57
  • Then go for the pi hat I would say in combination with the minimalmodbus library. The instructables site looks legit to me.
    – kyjanond
    Jun 15 '20 at 16:10
  • Thanks! will do!!
    – HenryHub
    Jun 15 '20 at 16:15

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