CST Analog & Digital Scale Technology 2

Question 1

Which type of load cell output signal is most commonly used in modern digital scales?

Accepted Answer

Millivolt per volt (mV/V)

Answer

Strain gauge load cells produce a millivolt-per-volt (mV/V) output proportional to applied load, which is the standard in digital weighing systems.

Question 2

An analog pointer scale exhibits a consistent 2% over-reading across its entire range. This is most likely caused by:

Accepted Answer

Incorrect span calibration

Answer

A uniform percentage error across the full range indicates a span (gain) calibration error rather than a zero or mechanical fault.

Question 3

In a digital indicator, what does the term 'resolution' refer to?

Accepted Answer

Smallest increment the display can show

Answer

Resolution is the smallest change in load that the indicator can detect and display, expressed as the number of display divisions.

Question 4

Which wiring configuration is used to compensate for resistance changes due to lead wire temperature fluctuations in remote load cell installations?

Accepted Answer

6-wire sense connection

Answer

A 6-wire connection uses separate sense lines that allow the indicator to measure and compensate for voltage drop caused by lead wire resistance changes.

Question 5

What is the purpose of a 'shunt calibration' resistor in a load cell system?

Accepted Answer

Simulates a known load by shifting bridge output a fixed amount

Answer

A shunt calibration resistor is placed across one bridge arm to produce a predictable mV/V shift, allowing electronic span verification without physical weights.

(CST) Certified Scale Technicians Practice Test

(CST) Certified Scale Technicians Practice Test

CST Analog & Digital Scale Technology 2