CWT CWT Troubleshooting & Maintenance 1

Question 1

A digital scale displays an unstable, fluctuating reading even with no load on the platform. What is the most likely cause?

Accepted Answer

Drafts, vibration, or electrical interference affecting the load cell signal

Answer

Unstable zero readings are most commonly caused by environmental factors such as air currents, vibrations, or electromagnetic interference disturbing the load cell's output signal.

Question 2

What is the recommended first step when a load cell-based scale consistently reads higher than the actual weight?

Accepted Answer

Perform a span calibration adjustment using certified reference weights

Answer

A consistent positive span error (reading high) indicates that the scale's gain needs to be adjusted downward, which is corrected through a span calibration using certified weights.

Question 3

During routine maintenance, a CWT discovers that the load cell cable insulation is cracked near the junction box. What is the correct course of action?

Accepted Answer

Replace or repair the cable before returning the scale to service

Answer

Damaged load cell cable insulation can allow moisture ingress and signal interference that degrades measurement accuracy, so the cable must be properly repaired or replaced before the scale is used.

Question 4

A vehicle scale fails the shift test, reading significantly lower when a test weight is placed at one end versus the other end. What component is most likely faulty?

Accepted Answer

One or more load cells or their wiring connections

Answer

Inconsistent shift test results on a multi-cell vehicle scale indicate that one or more load cells may be damaged, corroded, or have a loose wiring connection affecting their contribution to the total signal.

Question 5

What maintenance practice helps prevent the build-up of debris under a floor scale platform that can cause false readings?

Accepted Answer

Regular cleaning of the scale pit and checking that check rods and bumpers are free

Answer

Debris accumulation under a floor scale platform can mechanically bind the scale, causing it to support some load on the pit walls rather than the load cells, leading to false low readings.

(CWT) Certified Weighing Technician Practice Test

(CWT) Certified Weighing Technician Practice Test

CWT CWT Troubleshooting & Maintenance 1