Linear Scale

Using the Table Function in a DPM

The table function is used to define the relationship between the input signal and the output reading in a digital panel meter (DPM). This allows the user to implement a complex output function or correct system errors. Here are some examples where a table increases the versatility or improves the performance of a DPM. (more...)

Ground Detection Diagram

Ground Detection Voltmeter 101

A ground detection voltmeter is used to monitor a floating battery bank for inadvertent grounding on either side. Historically, a center zero analog meter has been used for this application. The meter typically has a 250μA, 500μA, or 1mA DC movement, with a voltage scale of 100-0-100 for a 72V battery bank, (more...)

Sine Waves

Current Sensing for Distorted Waveforms

Many AC current sensors work well on sine wave signals but cannot accurately determine the magnitude of distorted waveforms. Variable speed drives, electronic ballasts, LED bulbs, power converters, uninterruptible power supplies, and light dimmers are common sources of distorted current waveforms. Monitoring current in these devices requires careful equipment selection. (more...)


Tachometer Measurements

A tachometer is an instrument that measures the rate of rotation on a gasoline engine, electric motor, disk drive, or other spinning mechanism. The reading is usually displayed as revolutions per minute (RPM) in either analog or digital format. (more...)

analog synchroscope

What is a Synchroscope?

For two AC power systems to be interconnected (paralleled), they must be synchronized. This means they must be operating at the same voltage, the same frequency, and the same phase angle. Only when all three parameters match is it safe to connect the two systems. Paralleling two unsynchronized AC systems will cause a sudden current surge and mechanical stress on rotating equipment. (more...)