4-20mA Output Pressure | Temperature | Level Sensors

The 4-20mA output signal is an analog output signal commonly used in sensors.  It is typically powered by DC voltage ranging from 8-32 VDC, which are widely available commercially.

Occasionally, 4-20mA output signals use a three wire configuration (+V, -V, +S), but the vast majority of modern 4-20mA output sensors employ a two-wire, loop powered configuration with a supply (+V) and ground (-V).  The current (mA) is measured on the loop by reading the voltage across a known value resistor (often called a sense resistor).

Nearly all industrial level products from Core Sensors offer 4-20mA output options.

  • Output Signal
  • 4-20mA two wire, loop-powered

  • Excitation Voltage
  • 10-28VDC (for excitation as low as 8.5VDC, please contact factory)
  • Available from Core?
  • Yes

4-20mA Sensor Wiring Schematic

Advantages

  • Noise Immunity
  • No signal loss over long transmission distances
  • Compatibility with various power supplies and PLC’s because of high usage in general industry

Disadvantages

  • Current consumption is high when compared to a voltage output sensor
  • Need for at least 8VDC excitation, making for limited battery-powered options