4-20mA output problem

Using Arduino Project Guidance
1

Hello!

I have done a small project where I wanted to output 4 variables through 4 different 4-20 mA channels with an Arduino Mega. To do this I followed a 1 channel 4-20mA schematic that works through SPI that I found works perfectly:

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So what I did was to add 3 more 4-20 mA current loops and change the ADUM1411 digital isolator for an 8-channel digital isolator to get enough CS channels to control the added loops through SPI and placed this in a small pcb. And I got all the outputs to work properly except one.
My problem is that I did not realize that the digital isolator I got, an ADUM4151, one of the channels (Voc) works in the opposite direction ...
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Is there any solution/ hack to make it work like the other channels?

Sorry if I have not expressed myself with the proper technical terms.

Thank you!

2

I’m unsure what is going here - but the mega has enough digital outputs to do the bus and have enough pins for CS on each device and not use that miki bus thing . What are connecting to ? Do you need isolation or 4-20mA ?

You can’t fudge the connections on the chip I’m afraid , but if you prise the pins out of the board you could x wire them.( even hidden under the chip )

3

You could cut two PCB traces and wire the chip in the correct directions, but then you lose the isolation.

Probably better to rethink the project. Why do you want to use 4-20 mA communications?

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