Panel meters are instruments that display an input signal in an analog or digital form. Many panel meters also include alarm options as well as the ability to transfer data to a computer. They come in a wide variety of sizes, offering several mounting options and varying degrees of accuracy and resolution.
Panel meters can display speed, frequency, voltage, current, temperature, strokes per minute, feet per second, and more. Analog meters typically application specific and thus display one output. A digital device can be reconfigured to display a different value, like volts, amps, temperature or any other engineering unit.
To take and display measurements, panel meters take a sample of the voltage or current to create a visual representation of the measured value. Voltage measurements are read across the line, while current measurements are taken in series with the load.