Panel meter - common ground

[Zeebit]

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?

 

[Zeebit]

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.

 

[djQUAN]

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

 

[Zeebit]

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

Here is my setup:

 

[djQUAN]

I think it should work.

 

[Zeebit]

Time to give it a go then.

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