PO Instrumentation & Measurement 2

Question 1

What is the primary function of a control valve positioner?

Accepted Answer

To ensure the valve stem position accurately matches the controller output signal

Answer

To manually operate the valve from a remote control room location

Answer

To regulate only the supply air pressure to the pneumatic actuator

Answer

To convert the electrical signal into a digital process variable value

Question 2

Which type of temperature sensor generates a millivolt output based on the Seebeck thermoelectric effect?

Accepted Answer

Thermocouple

Answer

RTD (Resistance Temperature Detector)

Answer

Thermistor

Answer

Filled-bulb thermometer

Question 3

What is the standard current signal range used in most modern industrial field instrumentation loops?

Accepted Answer

4–20 mA

Answer

0–10 mA

Answer

0–20 mA

Answer

1–5 mA

Question 4

In a 4–20 mA instrumentation loop, what process condition does a reading of exactly 4 mA indicate?

Accepted Answer

The process variable is at 0% of its calibrated span

Answer

The transmitter has experienced an internal failure

Answer

The process variable is at 25% of its calibrated span

Answer

The loop power supply voltage has dropped below minimum

Question 5

What is the purpose of calibrating a process instrument?

Accepted Answer

To verify and adjust the instrument output to agree with a traceable reference standard

Answer

To physically clean the internal sensing element of contamination

Answer

To replace worn mechanical seals and internal components

Answer

To extend the instrument's measurement range beyond its design specification

Question 6

Which level measurement technology uses the hydrostatic pressure at the bottom of a vessel to determine liquid level?

Accepted Answer

Hydrostatic pressure transmitter

Answer

Radar level transmitter

Answer

Ultrasonic level transmitter

Answer

Capacitance level probe

Question 7

Which instrument is specifically designed to measure the viscosity (resistance to flow) of a process fluid?

Accepted Answer

Viscometer

Answer

Densitometer

Answer

Refractometer

Answer

Conductivity meter