Each DSCA33 True RMS input module provides a single channel of AC input which is converted to its True RMS DC value, filtered, isolated, amplified, and converted to standard process voltage or current output.

The field voltage or current input signal is processed through an AC coupled pre-amplifier and RMS converter on the field side of the isolation barrier. The converted dc signal is then filtered and chopped by a proprietary chopper circuit and transferred across the transformer isolation barrier, suppressing transmission of common mode spikes and surges. The computer side circuitry reconstructs, filters and converts the signal to industry standard outputs.

Module output is either voltage or current. For current output models a dedicated loop supply is provided at terminal 3 (+OUT) with loop return located at terminal 4 (-OUT). The system-side load may be either floating or grounded.

Special input circuits provide protection against accidental connection of power-line voltages up to 480VAC and against transient events as defined by ANSI/IEEE C37.90.1. Protection circuits are also present on the signal output and power input terminals to guard against transient events and power reversal. Signal and power lines are secured to the module using screw terminals which are pluggable terminal blocks for ease of system assembly and reconfiguration.

DSCA33 modules have excellent stability over time and do not require recalibration, however, both zero and span settings are adjustable to accommodate situations where fine tuning is desired. The adjustments are made using potentiometers located under the front panel label and are non-interactive for ease of use.

Read our Application Note 101, Measuring RMS Values of Voltage and Current.
  • Interfaces RMS Voltage (0 – 300V) or RMS Current (0 – 5A)
  • Designed for Standard Operation with Frequencies of 45Hz to 1000Hz (Extended Range Operation to 20kHz)
  • Compatible with Standard Current and Potential Transformers
  • Industry Standard Output of either 0-1mA, 0-20mA, 4-20mA, 0-5V, or 0-10VDC
  • ±0.25% Factory Calibrated Accuracy (Accuracy Class 0.2)
  • ±5% Adjustable Zero and Span
  • 1500Vrms Transformer Isolation
  • Input Overload Protected to 480V (Peak AC & DC) or 10A RMS Continuous
  • ANSI/IEEE C37.90.1 Transient Protection
  • Easily Mounts on Standard DIN Rail
  • C-UL-US Listed
  • CE and ATEX Compliant
Isolated True RMS Input Signal Conditioners

DSCA33 Devices


Part Number Input RangeOutput RangeMechanical FormatIsolation VoltageIsolation Type
0 to +100 mV 0 to +10 V DIN rail 1500 Vrms Transformer 3-way
0 to +100 mV 0 to +5 V DIN rail 1500 Vrms Transformer 3-way
0 to +100 mV 0 to 1 mA DIN rail 1500 Vrms Transformer 3-way
0 to +100 mV 4 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to +100 mV 0 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to +1 V 0 to +10 V DIN rail 1500 Vrms Transformer 3-way
0 to +1 V 0 to +5 V DIN rail 1500 Vrms Transformer 3-way
0 to +1 V 0 to 1 mA DIN rail 1500 Vrms Transformer 3-way
0 to +1 V 4 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to +1 V 0 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to +10 V 0 to +10 V DIN rail 1500 Vrms Transformer 3-way
0 to +10 V 0 to +5 V DIN rail 1500 Vrms Transformer 3-way
0 to +10 V 0 to 1 mA DIN rail 1500 Vrms Transformer 3-way
0 to +10 V 4 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to +10 V 0 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to +150 V 0 to +10 V DIN rail 1500 Vrms Transformer 3-way
0 to +150 V 0 to +5 V DIN rail 1500 Vrms Transformer 3-way
0 to +150 V 0 to 1 mA DIN rail 1500 Vrms Transformer 3-way
0 to +150 V 4 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to +150 V 0 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to 300 V 0 to +10 V DIN rail 1500 Vrms Transformer 3-way
0 to 300 V 0 to +5 V DIN rail 1500 Vrms Transformer 3-way
0 to 300 V 0 to 1 mA DIN rail 1500 Vrms Transformer 3-way
0 to 300 V 4 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to 300 V 0 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to 1 A 0 to +10 V DIN rail 1500 Vrms Transformer 3-way
0 to 1 A 0 to +5 V DIN rail 1500 Vrms Transformer 3-way
0 to 1 A 0 to 1 mA DIN rail 1500 Vrms Transformer 3-way
0 to 1 A 4 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to 1 A 0 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to 5 A 0 to +10 V DIN rail 1500 Vrms Transformer 3-way
0 to 5 A 0 to +5 V DIN rail 1500 Vrms Transformer 3-way
0 to 5 A 0 to 1 mA DIN rail 1500 Vrms Transformer 3-way
0 to 5 A 4 to 20 mA DIN rail 1500 Vrms Transformer 3-way
0 to 5 A 0 to 20 mA DIN rail 1500 Vrms Transformer 3-way

Frequently Asked Questions


Can Dataforth provide calibration reports for modules I purchased?
Yes we can provide calibration reports for the modules that you purchased.

You can either
a) visit https://www.dataforth.com/TestDataReport.aspx to search for Test Report Datasheets by Serial Number or
b) you can send us a list of model numbers and their serial numbers to support@dataforth.com

Can you explain what is the difference between the “Standard frequency range” and the “Extended frequency range” for the DSCA33 module?
The user does not have to do anything special; the module operates seamlessly over the full frequency range of 45Hz to 20kHz. We needed to split the full frequency range into two ranges so we could define and specify the different accuracy levels associated with each subrange.
If you look further down the DSCA33 Specifications under Accuracy, you will notice the Standard frequency range from 45Hz to 1kHz carries an additional +/-0.25% Reading error. This error is in addition to the +/-0.25% Span error at 50/60Hz. So the total accuracy error will be +/-0.25% Span + (+/-0.25% Reading) = +/-0.50%.
And the Extended frequency range from 1kHz to 20kHz carries an additional +/-0.75% Reading error. This error is in addition to the +/-0.25% Span error at 50/60Hz. So the total accuracy error will be +/-0.25% Span + (+/-0.75% Reading) = +/-1.00%.

Keywords/Phrases: DSCA RMS, DSCA True RMS, DSCA RMS input module, DSCA True RMS input module, DSCA33

Is there an extra charge for the extended frequency range to 20kHz for a DSCA33-01C?
There is no extra charge for the extended frequency range in the DSCA33. If you look in the DSCA33 Specifications under Accuracy, you will notice the extended frequency range carries an additional +/-0.75% of Reading error. This error is in addition to the +/-0.25% Span error at 50/60Hz. So the total accuracy error will be +/-0.25% + (+/-0.75%) = +/-1.00%.

For a half-wave rectified sine, Crest Factor = 2, in a DSCA33, which additional error spec do I apply; the one for Crest Factor 1 to 2 or 2 to 3?
The DSCA33 Crest Factor additional error is specified in several ranges of 1 to 2, 2 to 3, 3 to 4, and 4 to 5. For every whole number Crest Factor 2 and greater, choose the pair with the applicable whole number to the right. That whole number is included in the range or mathematically: <=. The whole number at the left of a range is excluded from the range or mathematically: >.

Keywords/Phrases: DSCA33, Crest Factor, DSCA33 and Crest Factor