I'm hoping some electronic guru can assist. I'm building a power control system for a 3d printer and part of the system will measure voltage/amperage of various parts of the system - hotbed/hotend/control system.
I've bought these cheap Ammeter units with shunts here: https://www.ebay.com.au/itm/252487705726
They have been wired up as per the diagram but I've run into a slight issue, the units need a seperate power supply to the one I am measuring otherwise it won't read the load. I'm assuming it's not liking the common ground (or common source voltage).
I really don't want to run a seperate power supply just for the LCD units - does anyone have any suggestions or tricks to isolate the LCD power but still use the same source power supply?