Hello forum,
I'm having a problem which I do not quite understand. In the past I have dealt with Arduinos freezing up when you have a relay switching on/off 220V contactors or loads, and I have successfully solved this by using capacitors and resistors over the relay contacts.
I've now bumped into something different, although I suspect it may be similar in a way. I built a device that sends water pressure signal to a VSD (ABB ACS580) using 0-10V signal. I do this with a Mega and a 0-10V DAC (https://store.ncd.io/product/1-channel-0-10v-dac-digital-analog-converter-i²c/)
When testing the device for a number of days it operates very well, sends the correct corresponding 0-10V signal (measured with a DDM) and the system never ever freezes up. Yesterday however, when I connected the system up to the VSD, and specifically when I start the VSD, suddenly the systems started acting up and freezing. I measured the voltage on the leads coming from the VSD but couldn't pick up a voltage coming back from the VSD, although I suspect this may be happening at times. I just cannot think of any other reason why the Arduino would hang.
My question is how to avoid any potential current or voltage coming back from the VSD while not influencing the 0-10V that goes to the VSD.
In the manual there is this line, which probably holds the key, but with my complete lack of experience with electronics and components, I'm not sure what this means or how it would be connected (see attachment.)
Many thanks,
Hein
