Analog & Digital Panel Meters Considerations

A digital panel meter provides useful machine and process condition readings as well as a wealth of additional functions. Because of these additional functions, a digital panel meter is more complex and expensive than an analog panel meter, which is the reason why you may still want to use an analog panel meter.

If the machine or process operates as expected within a specific range, an analog panel meter is an especially cost-effective way to provide a visual clue to system performance. Because it draws power from the input signal, an analog panel meter does not require an external power source, and a typical analog meter has a plus-minus two percent accuracy sufficient for many applications, examples of which include using the input frequency of an AC signal to indicate AC frequency or using an analog panel meter as a time meter. Common input signals include AC or DC amps or volts and custom scales are possible as well.

Since a typical digital panel meter has an accuracy of plus-minus 0.05% or less, you will want to use a digital panel meter when you need very precise readings. Digital panel meters can also offer communication, real-time control, and output functions as well as signal conversion, wireless communication with sensor networks, and web server capability.

In addition to offering signal conversion and retransmission, certain digital panel meters can be used for alarming applications, providing two independent alarms that may be configured for low and high set points and an assortment of latching sequences. Some models even feature an analog output signal proportional to the the input for retransmission.

While they may be easy to program and maintain, panel meters are capable of controlling rather sophisticated operations like scaling and weighing. A digital panel meter with an embedded web server enables you to connect to the panel meter via web browser, enabling remote real-time control. Some panel meters can be configured for PID or on/off control and output options include isolated programmable analog voltage/current, pulse, solid-state relays, and SPDT relays.

The transducer inputs of a digital panel meter can be hardwired or wireless. Point-to-point extended range wireless transmitters and powerful NEMA-extended range transmitters support a variety of transducers that offer greater flexibility when setting up your system. You can find ⅛ DIN panel meters and controllers capable of monitoring as many as eight wireless sensors. These compact panel meters can directly connect to your Ethernet network or may be connected to a computer via USB port and Ethernet adapter.

George

George Leger has a Masters in Electrical Engineering from Stanford University, worked in private industry pioneering surface-mount technology and in government research labs for twenty years, published several papers on surface-mount technology, co-authored papers published in national symposiums on accelerator technology, was past president of SMTA and an adjunct professor at the community college level, holds a patent, and is a certified microchip design partner, serving as a consultant to many companies developing electronic circuits.

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