I have a device that controls the speed of a variable speed drive. I use a MEGA 2560 with this 0-10V DAC by ncd.io:
The MEGA is powered from a 220VAC to 12VDC converter (3A rating) and this 12VDC I send through a DC-DC converter down to 7.5V, which goes to the MEGA. I do this in an attempt to clean and steady the DC a bit more.
When I installed the unit the MEGA would freeze immediately when the VSD was powered on. This was fixed by closing one of the pull-up resistor jumpers. The unit worked fine for many months.
Recently it started to freeze up again, so I closed the second pull up resistor jumper too, worked ok for a while and now it is working intermittently. As soon as the VSD is shut down my unit doesn't seem to have any problems.
The unit is mounted about 4 meters away from the VSD. What would be the most likely culprit? Noise through the power supply or noise coming back from the 0-10V line?
And what would the solution be?