Panel meter - common ground

Edit: Topic changed.

Okay, so I still have not finished building my CC/CV PSU (thanks to djQUAN for a lot of help) because of some circumstances.

Anyway, I've ditched my plan of getting a particular panel meter and just go cheapo. I'm looking at this ammeter.

It says that it needs an isolated power supply but I don't want to add an isolated module to save some space on the pcb. Is there a way to use this on without an isolated supply? Something like a differential input? I don't even know how it works.

I've seen similar meters that do not have a built in shunt but the pcb and components look the same and in the description I found this diagram (below). Would this work with the meter above?





Edit again: Since the meter I'm looking at has a built in shunt, I'm thinking about connecting its input to the negative side of the circuit I need to measure. Is this gonna work?

Yeah, but I just want to know if somebody has one of these meters so that I could know the resistance before I buy one.

Thread changed.

Meter shunt are the two white ceramic resistors beside the current input wires. I'm guessing they are two 0.1ohm resistors in parallel.

I'm thinking about getting that meter with the built in shunt. Can I use it without an isolated supply?

Here is my setup:

I think it should work.

Time to give it a go then.

Care to explain why this method works with meters that require an isolated power supply?