CAS CAS Automation Specialist Instrumentation & Sensors

Question 1

What does the '4-20 mA' standard represent in industrial instrumentation?

Accepted Answer

A current loop signal range where 4 mA represents 0% and 20 mA represents 100% of span

Answer

A voltage range for digital signals

Answer

A resistance value for RTD calibration

Answer

A frequency range for vibration sensors

Question 2

Which type of flowmeter measures flow by detecting the frequency of vortices shed by an obstruction in the flow stream?

Accepted Answer

Vortex flowmeter

Answer

Coriolis flowmeter

Answer

Magnetic flowmeter

Answer

Ultrasonic flowmeter

Question 3

What is the primary advantage of a Coriolis mass flowmeter over a volumetric flowmeter?

Accepted Answer

It directly measures mass flow, independent of fluid density, temperature, or pressure

Answer

Lower installation cost

Answer

It works better with slurries

Answer

It requires no upstream straight pipe runs

Question 4

An RTD (Resistance Temperature Detector) operates on which physical principle?

Accepted Answer

The predictable change in electrical resistance of a metal with temperature

Answer

The Seebeck effect, where two dissimilar metals generate a voltage

Answer

The change in capacitance of a dielectric with temperature

Answer

The resonant frequency shift of a crystal with temperature

Question 5

In process instrumentation, what does the term 'rangeability' refer to?

Accepted Answer

The ratio of maximum to minimum flow that an instrument can measure accurately

Answer

The maximum operating pressure of an instrument

Answer

The electrical signal range of a transmitter output

Answer

The temperature range over which calibration is valid

Question 6

Which pressure measurement term describes pressure referenced to absolute zero (perfect vacuum)?

Accepted Answer

Absolute pressure

Answer

Gauge pressure

Answer

Differential pressure

Answer

Atmospheric pressure