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663 Views - Created 07/09/2018
I’m using the RS485 PI. I’ve connected 3 Kaco Inverters to it, the last one is not answering. A termination resistor is added at the end.
I’ve also got an USB RS485, this one is working with all three inverters.
Does someone has an advice?
Are you using a shielded twisted pair cable to join the inverters together? It is possible that the RS485 Pi is more sensitive to noise than your USB device so a twisted cable will give you better noise performance. Maxim has a good article on wiring an RS485 network at https://www.maximintegrated.com/en/app-notes/index.mvp/id/763
You could also try adding a 10K resistor between the Raspberry Pi’s 5V pin and the A output on the RS485 Pi and a second 10K between the ground and B output. This should make the RS485 Pi less susceptible to noise and hopefully solve the problems you are having.
Thank you very much, it works great!
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