Load Cell Troubleshooting: Causes & Fixes

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Problems on this page:

Weight reading drifting Scale not returning to zero Corner or section error on a platform scale Unstable weight during filling or dosing Damaged by overload or welding Cable or junction box faults Calibration failing tolerance Wrong weight in the control system

Weight reading drifting

Hits OEE: Quality

Symptoms: The scale or weigh vessel shows a slowly changing weight with nothing added or removed.

Temperature changes on the load cell or vessel

Check whether the drift follows the temperature and shield the cells from heat sources.

Moisture in the load cell or junction box

Check the junction box for water and the cable glands for sealing.

Pipework or cables pulling on a weigh vessel

Check that connected pipes and hoses are flexible and do not take load.

Load cell overloaded at some point

Check the zero balance of each cell against its certificate.

Prevention: Zero and span checked with test weights at the interval the quality system sets.

Scale not returning to zero

Hits OEE: Quality

Symptoms: The scale shows a weight when empty, and batches start from a wrong tare.

Material build-up on the platform or vessel

Clean the weighing surface and check for product stuck in the vessel.

Something touching the weighed part

Check for guards, cables or debris bridging between the weighed part and the frame.

Load cell damaged by a shock load

Check each cell separately for a zero shift.

Auto-zero range set too small

Check the zero tracking settings in the indicator.

Prevention: Zero checked at the start of each shift.

Corner or section error on a platform scale

Hits OEE: Quality

Symptoms: The same test weight reads differently in different places on the platform.

One load cell weaker or damaged

Test each corner with a test weight and check each cell output.

Corner adjustment not done

Run the corner adjustment as the indicator maker describes.

Platform not level or a foot not carrying load

Check the mounting feet and the level of the platform.

Junction box trimming changed

Check the trim settings in the junction box.

Prevention: Corner test done during calibration.

Unstable weight during filling or dosing

Hits OEE: Quality

Symptoms: The weight bounces while filling, and doses end over or under target.

Vibration from nearby machines or the agitator

Check the mounts and isolate the scale from vibration sources.

Filter setting too weak for the duty

Increase the indicator filter while keeping the response fast enough for dosing.

Air drafts on a sensitive scale

Fit a draft shield.

Product impact during filling

Check the filling speed and the fine-feed setting near the target.

Prevention: Dosing accuracy checked against the target on samples.

Damaged by overload or welding

Hits OEE: Availability

Symptoms: A load cell fails after an impact, overload or welding work nearby.

No overload stops fitted

Fit or adjust overload stops on the mounts.

Welding current passed through the cell

Earth welding sets close to the work and bypass or remove the cells; welding current can destroy a load cell.

Forklift or crane impact

Protect the scale from impacts.

Side loads on the mount

Check the mounts allow movement in the right directions.

Prevention: Load cell failures recorded with their cause.

Cable or junction box faults

Hits OEE: Availability

Symptoms: The indicator shows an error, or the weight jumps when the cable is moved.

Cable damaged or crushed

Inspect the cable route and protect it.

Water in the junction box

Dry it and replace the seals and glands.

Loose terminal

Check the terminals in the junction box.

Rodent or chemical damage

Check the cable jacket along the route.

Prevention: Junction boxes inspected during planned maintenance.

Calibration failing tolerance

Hits OEE: Quality

Symptoms: A calibration with test weights shows errors beyond the tolerance for the scale.

Test weights out of date or not certified

Check the test weight certificates and their class for the scale.

Span settings in the indicator changed

Compare the indicator settings with the last calibration record.

Something restricting the movement of the weighed part

Check for mechanical binding at mounts, check rods and connected pipes.

One or more cells ageing

Test each cell and replace those that fail.

Prevention: Calibration records reviewed after every calibration.

Wrong weight in the control system

Hits OEE: Quality

Symptoms: The weight indicator and the control system show different values.

Scaling mismatch between indicator and control system

Check the scaling of the analogue or fieldbus value at both ends.

Units differ

Check that both use the same units.

Slow update rate on the communication

Check the update rate for fast dosing duties.

Wrong channel mapped

Check the tag mapping in the control system.

Prevention: Indicator and control system weights compared at commissioning and after changes.

Guidance only. Always follow lockout/tagout and your site's safe-work procedures, and verify against OEM manuals before acting.

Related equipment guides: checkweigher · belt weigher · multihead weigher · silo / hopper · PLC

Stop the same fault coming back

Recurring load cell stops usually trace to a cause you cannot see by hand. The partner we recommend is Fabrico: it tracks OEE and downtime live from PLCs, IoT sensors or AI cameras; where cameras are fitted, the video of a stop sits next to its machine data so the cause can be reviewed; and a technician opens the work order from the stop in the same system. Data is hosted in the AWS EU region, and Fabrico and the company behind it hold ISO/IEC 27001, ISO/IEC 20000-1 and ISO 9001.

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Methods that cut recurring stops: the six big losses · root cause analysis · preventive vs predictive maintenance · TPM · SMED & changeover