EETC Instrumentation 4

Question 1

A transmitter with a 0.1% accuracy specification on a 0-100 psi range has a maximum error of:

Accepted Answer

0.1 psi

Answer

0.1% of full span (100 psi) = 0.1 psi maximum allowable error across the calibrated range.

Question 2

What does 'turndown ratio' describe in flow measurement?

Accepted Answer

The ratio of maximum to minimum measurable flow with acceptable accuracy

Answer

Turndown (rangeability) is the ratio of the maximum flow the meter measures accurately to the minimum, e.g., 10:1 means it reads correctly from 10% to 100% of full scale.

Question 3

In a PLC analog input module, a broken 4-20mA signal wire most commonly causes the reading to go to:

Accepted Answer

0mA, triggering a below-range fault

Answer

An open circuit allows no current to flow (0mA), which falls below the live zero (4mA) and should trigger a wire-break alarm in the control system.

Question 4

An ultrasonic level transmitter using the time-of-flight (TOF) method measures:

Accepted Answer

The reflection time of a sound pulse from the liquid surface

Answer

TOF ultrasonic sensors measure the time for an emitted pulse to travel to the liquid surface and return, then calculate distance using the speed of sound.

Question 5

Which ISA instrument tag designation indicates a flow indicating controller?

Accepted Answer

FIC

Answer

Per ISA-5.1, F=Flow, I=Indicating, C=Controller, so FIC is a flow instrument that both displays the measured value and provides control output.

(EETC) Electrical Technician Certification Practice Test

(EETC) Electrical Technician Certification Practice Test

EETC Instrumentation 4