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MODEL2168-002、MODEL2168-002、MODEL2168-002、

Offering a high-accuracy 4 1/2-digit display of true RMS voltage for five ranges, this Digital Panel Meter (DPM) is intended for AC applications where there is considerable waveform distortion from nonlinear loading. The 2168's input is AC-coupled to read only the AC component, such as ripple on a power supply.

The meter uses precision circuitry to compute the root-mean-square value of complex waveforms from 10 Hz to 10 kHz. Spikes of up to 2.4 times the maximum of each input range are accuray measured. This provides a crest factor (Vp/Vrms) of 240 for a signal amplitude of 1% of full scale, decreasing to 2.4 at * of full scale.

High common-mode rejection allows stable readings with current shunts located on the high side of the line. Digital scaling and calibration eliminate zero and span drift associated with potentiometers in non-microcomputer based meters.

While observing the same high-speed A/D conversion rate as all other 2000 Series DPM's, the Model 2168's settling time and control response to a step change in AC amplitude are limited by the RMS converter circuit to approximay 1 second.

Typical 2168 accuracy is 99.9% of full scale (decreasing to 99.8% for low frequency at high amplitude, or high frequency at low amplitude. The following graph shows maximum full-scale error as a function of frequency and signal amplitude. Error is 0.1% of full scale over all frequency ranges of interest to AC power measurement. Error increases to 0.2% at low frequency and high amplitude, or at high frequency and low amplitude. Increasing in inverse proportion to signal amplitude, the maximum crest factor is 2.4x.

All voltage ranges are calibrated at the factory, with calibration factors for each range stored in internal EEPROM. This allows ranges to be changed in the field without having to recalibrate the meter.

As with all 2000 Series DPM’s, the peak value of the input signal is automatically captured and may be displayed via front-panel push button or a control signal received at the rear connector (since the last meter reset). Data readings and outputs can be separay selected to be either filtered or unfiltered.

2000 Series options applying to the RMS voltage meter include

• Isolated Relay Outputs
• Isolated Analog Output
• RS232 or RS485 Interface
• Low AC/DC Power