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Overview of Sensor Output Signals

Apr 10, 2025

Sensor Output Signals Overview

Introduction

  • Sensors transmit measurements to control systems via electrical signals.
  • Choosing the right sensor signal output is crucial for applications.

Common Sensor Output Signals

  1. DC Voltage

    • Description: Uses analog voltage to transmit measurements.
    • Common Voltage Ranges: 0 to 5 volts DC and 0 to 10 volts DC.
    • Diagram Explanation:
      • Connected in parallel with resistors (R1, R2, R3) representing different devices (panel meter, controller, data logger).
    • Advantages:
      • Simple and relatively inexpensive.
      • Compatible with nearly all industrial meters and controllers.
    • Disadvantages:
      • Voltage drop across cable runs affects accuracy.
      • Susceptible to electromagnetic noise and interference.
      • Requires 3-4 wires (2 for supply/excitation voltage, 2 for output voltage).

  2. 4 to 20 Milliamp Current Loop

    • Description: Converts the sensor's output to a current signal.
    • Functionality:
      • 0 milliamps indicates an open circuit/lost feed.
    • Advantages:
      • Easy wiring (only 2 wires needed).
      • Not affected by electrical noise.
      • Current level remains constant, ensuring accuracy despite voltage drops.
      • Limited only by the power supply voltage.
    • Disadvantages:
      • Each sensor needs its own cable run to power supply and receiver.
      • Information only sent one way (to/from instrument).

  3. Millivolt per Volt Output Signals

    • Description: Used mainly in pressure transducers or load cells.
    • Functionality:
      • Output voltage is a ratio of the excitation voltage required for the sensor.
      • Example: 2 mV/V with 5V excitation results in 10 mV output.
    • Advantages:
      • Low cost, fast response times, smaller size.
    • Disadvantages:
      • Requires a regulated power supply for excitation voltage.
      • Shorter signal ranges and vulnerable to electromagnetic interference.

Conclusion

  • Summary of three commonly used sensor output signals.
  • For further assistance, contact engineering experts at omega.com.

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