Analog & Digital Scale Technology Flashcards
7 cards from real CST practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Analog & Digital Scale Technology flashcards as text
Which type of load cell output signal is most commonly used in modern digital scales?
Answer: Millivolt per volt (mV/V)
Strain gauge load cells produce a millivolt-per-volt (mV/V) output proportional to applied load, which is the standard in digital weighing systems.
An analog pointer scale exhibits a consistent 2% over-reading across its entire range. This is most likely caused by:
Answer: Incorrect span calibration
A uniform percentage error across the full range indicates a span (gain) calibration error rather than a zero or mechanical fault.
In a digital indicator, what does the term 'resolution' refer to?
Answer: Smallest increment the display can show
Resolution is the smallest change in load that the indicator can detect and display, expressed as the number of display divisions.
Which wiring configuration is used to compensate for resistance changes due to lead wire temperature fluctuations in remote load cell installations?
Answer: 6-wire sense connection
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.
What is the purpose of a 'shunt calibration' resistor in a load cell system?
Answer: Simulates a known load by shifting bridge output a fixed amount
A shunt calibration resistor is placed across one bridge arm to produce a predictable mV/V shift, allowing electronic span verification without physical weights.
A digital bench scale displays an unstable, flickering reading even with no load on the platform. The most likely cause is:
Answer: Electrical interference or ground loop
Unstable no-load readings on a digital scale are typically caused by electrical noise or ground loops entering the signal path.
What is meant by 'creep' in a strain gauge load cell?
Answer: Slow drift of the output signal under constant applied load over time
Creep is the change in load cell output that occurs over time while a constant load remains applied, caused by stress relaxation in the elastic element.