Panel Meters 

What is a panel meter?

Panel meters are instruments that display an input signal in analog or digital form. Many panel meters also include alarm options and the ability to transfer data to a computer. Panel meters take a sample of the voltage or current to create a visual representation of the measured value. Voltage measurements are taken across the line while current measurements are taken in series with the load, sometimes using shunts or current transformers when the load current exceeds 10 amps.

Overload protection device. When used in such applications, they are often referred to as Motor Protection Circuit Breakers (MCPs).

Analog Panel Meters

 The interface is application specific and can display any unit of measure with almost any input signal representative of the process. An analog meter can display speed, frequency, voltage, current, temperature, strokes per minute, or feet per second. The actual input signals are analog voltage or current, either AC or DC. An example is 0 to 10 volts DC, four to 20 milliamps DC, or 0 to 100 volts DC. Digital gauges work the same as
; however, digital meters often also include the digital scale of the display relative to the input signal.

Analog gauges have two methods of displaying readings. The first is a taut strap, with the needle suspended between two metal straps, ideal for high-impact environments. The other method is a fulcrum and jewel where the pointer is more stable for higher vibration environments.

Digital Panel Meters

Among the different types of panel meters, digital panel meters offer the highest resolution. This is often confused with precision, but analog gauges can be just as accurate as digital gauges. Digital gauges offer a more readable display, especially in low light conditions, and also offer higher resolution. Readings can be the same between an analog and digital meter, but in cases where the input signal is constantly changing, the analog meter may be preferable. Using a motor as an example, the panel meter could be hooked up to a shunt or CT to see how many amps a motor is drawing at any given time.

To ensure the motor is approaching 20 amps, an analog meter can give a good visual indication of how many amps are being drawn. As the torque increases or decreases, the pointer will fluctuate within the range of the indicator. As for the digital counter, the constant changing of the numbers makes it difficult to read. Of course, this does not apply to all applications. With the digital display, the display is much easier to see at a glance than with an analog display.

Digital panel meters can also offer extended functionality. A digital meter can be reconfigured to read volts, amps, temperature, or any other engineering unit. Relay outputs are sometimes available, allowing the meter to control a process based on the measured input signal or reading.