Standard input signal

HI! i would like to inquire.. is there a -20 to 20mA signal??...

yes

the reactive power meter has an input signal og -20mA to 20mA... can i use 0 to 20mA instead of -20mA to 20mA... it seems the reactive power meter is too old..

You now have three posts about apparently the same thing.

Why don't you post, oh, I don't know, some ACTUAL information about what you are trying to do.

Device Part Numbers, Manufacturers, HMI type...

And don't start another thread for it.

post a picture your old meter

The host with the analog input does not know what the ±20mA (bipolar) signal represents nor does it know what a 4-20mA (unipolar) signal represents or any range analog signal, for that matter, you have have to tell it what the signal represents. You assign a meaningful range and engineering units (in the development software) for the analog signal.

You would use a ±20ma-to-4-20mA signal conditioner/converter in order to use a conventional analog input card. But both signals cover the same range, it's up to you to define the range and the units.

A unipolar 4-20mA signal can easily represent a bipolar signal:
4mA = -20 units
8mA = -10 units
12mA = 0 units
16mA = +10 units
20mA = +20 units