True AC RMS Voltage or Current 4-20 mA Current Transmitter

Laureate 4-20 mA output, AC RMS input transmitters provide six voltage ranges and four current ranges, all factory calibrated and jumper selectable. The 200.00 mV and 2.0000 V ranges provide a high input impedance of 22 Mohm to minimize the load on the voltage signal. A special 5.000A range accepts the output of 5A current transformers, with no need for a stepdown transformer. The current readings can easily be scaled digitally as needed.

True RMS precision circuitry is used to determine the root-mean-square of complex waveforms from 10 Hz to 10 kHz. Spikes up to 2.4 times the maximum of each range are accurately measured. This provides a crest factor (Vp / Vrms) of 240 for a signal amplitude of 1% of full scale, decreasing to 2.4 at 100% of full scale.

Maximum error as a function of frequency and signal amplitude

Laureate AC RMS input transmitters duplicate the performance and programmable features of their Laureate AC RMS digital panel meter counterparts. Features include optional dual solid state relays for local alarm or control. The transmitters are housed in a DIN rail case that is only 22.5 mm (0.89") thick. Signal connections are via detachable screw-clamp plugs.

In addition to the 4-20 mA output that would typically be used for signal transmission in an industrial environment, a 0-10V analog output is selectable. Either selection provides 12-bit (0.025%) resolution of output span and is ultra-linear to within one bit. The output tracks the reading that would be transmitted digitally. For AC RMS signals, output accuracy is ±0.1% of full scale input.

Transmitter programming is via a three-terminal RS-232 port using Laurel's PC-based Instrument Setup Software. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from Laurel (P/N CBL03).