Digital Panel Ammeter Wiring
With the aim to clear up confusion around wiring and powering digital panel mount ammeters, we have put together the following article covering the two main ways that digital panel ammeters should be wired and used. Although your digital ammeter may differ from models in these examples. The basic wiring principle and common ground issue will be the same.
Generally digital panel mount ammeters (including Mr Positive models) require a separate independent power supply for their operation. This is a result of issues surrounding the meter power source sharing a common ground with the input. If the meter is wired so that the power source shares ground with the input, the meter will be damaged beyond repair.
General Wiring Diagram
Due to the meters design it is not possible for the meter power source to share ground with the input. In this example the meter is wired to manufacturer specifications, where a separate power source such as a completely separate battery, is solely used to power the meter. This is similar to using a multimeter that requires a 9v battery for its running power.
In this diagram a separate battery is solely used to power the meter. Although this is completely functional, the issue is with permanent installations, such as motor homes, marine and generators, where this battery would need to be replaced regularly.
Using Isolated Voltage Regulator Module
By using an Isolated Voltage Regulator Module we are able to power the meter from the same power source, as the ground is now isolated from the input. The Isolated Voltage Regulator Module isolates the ground, providing a completely isolated power source to the meter.
Mr Positive currently carries a low wattage Isolated Voltage Regulator Module located here.
In wiring the meter the Isolated Voltage Regulator Module is placed in line between the meters positive and negative power supply input. Although some digital ammeters can operate from both AC and DC power sources and as a result do not have polarity, the Isolated Voltage Regulator Module does have set positive and negative input / output pins. It is important to follow manufacturer specs when wiring the module.
This solution is ideal for permanent ammeter installations.