REG 21

Differential pressure transmitter in control panel housing with two limit contacts

Technical data
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Differential pressure transmitter in control panel housing with two limit contacts

Special features

  • Accurate measurement of differential pressure with automatic zero-point calibration and high overload protection
  • Switching outputs can be used as 2-point regulator (pressure switch), for activating / deactivating a final control element (e.g. pump), with relay hysteresis
  • Switching outputs can be used as a 3-point regulator (e.g. ON 1 - OFF - ON 2) for activating / deactivating two final control elements, (e.g. air intake / outflow fans), with relay hysteresis
  • Asymmetry also possible, e.g. 10 .. 40 mbar
  • High level of accuracy and long-term stability
  • Very little hysteresis; largely independent of temperature
  • 4 1/2 digit LED display
  • Output signal 0 .. 10 V, ± 5 V or 0/4 .. 20 mA
  • Selectable attenuation of the output signal up to 10 s
  • Choice of transistor or relay outputs as limit contacts
  • Can be calibrated

This differential pressure transmitter in a control panel housing is suitable for use as a 2- or 3-point controller thanks to its two integrated limit contacts. These enable low cost control without the need for additional electronics e.g. activating or deactivating a pump. Both the threshold values and the hysteresis for the controller are easy to set via the front keypad. The display provides readings of measurement values directly on-site in Pa, kPa, inchH₂O or mmH₂O as well as information about the output states of the limit contacts. An adjustable time constant (up to 10 s) allows the instrument to generate an attenuated output signal, even under fluctuating pressure conditions. Cyclical self-calibration of the zero point ensures a high level of measurement accuracy. 


  • Available with an factory calibration certificate or calibration certificate according to DKD-R 6-1 (optional).
Measurement ranges
50 / 100 / 200 / 500 Pa1 / 2.5 / 5 / 10 / 20 / 50 / 100 kPaOthers available upon request
Margin of error (0,3 Pa for the reference)
± 0.5 % of max. value± 1 % of max. value (standard)
Output (signal)
0 .. 10 V (RL ≥ 2 kΩ)± 5 V (RL ≥ 2 kΩ)0/4 .. 20 mA (RL < 500 Ω) adjustable

4 1/2 digit

Protection class

IP 50

Contact points
2 relays with floating changeover contacts 230 VAC (50/60 Hz), 6 A (optional)2 transistors with open collector UCE ≤ 50 V; IC ≤ 200 mA, floating
Power supply
24 VDC, +20 % / -15 %24 VAC, +6 % / -15 %115 VAC, +6 % / -15 %230 VAC, +6 % / -15 %
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