The GATE Grind

GATE 2021 CH – Question 21

Instrumentation and Process Control · Measurement of process variables, sensors, transducers and P&ID symbols · 1 mark · Multiple choice

Which of the following is NOT a standard to transmit measurement and control signals?

  1. 4–20 mA
  2. 3–15 psig
  3. 0–100%
  4. 1–5 VDC

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Show answer and explanation

Correct answer: (C) 0–100%

Explanation

A transmitted instrument signal uses a physical range: **4–20 mA** is a standard current signal, **3–15 psig** is a pneumatic signal, and **1–5 VDC** is a voltage signal.

**0–100%** describes a normalized fraction of an instrument’s span or a controller output. It does not specify the physical signal used for transmission. **Answer: C.**