Force Measurement Troubleshooting and Accuracy Guide
Force measurement accuracy depends on proper installation, environmental control, and regular verification. This guide covers common problems and solutions.
I. Common Error Sources
Off-Axis Loading: Force not applied along the primary measurement axis. Use rod end bearings or self-aligning adapters to minimize side loads and bending moments.
Temperature Effects: Load cells have specified compensated temperature ranges. Operation outside this range causes zero and span shifts. Use temperature-compensated load cells for varying environments.
Electrical Noise: Use shielded cables with the shield connected at the instrumentation end only. Route signal cables away from power cables and VFD outputs.
Moisture Ingress: Causes unstable readings and corrosion. Use hermetically sealed load cells in wet environments. Check cable glands and seals regularly.
II. Troubleshooting
Zero Drift: Check for temperature changes, moisture ingress, or mechanical binding. Allow warmup time for the signal conditioning electronics.
Non-Repeatable Readings: Check for loose mounting hardware, debris, or friction in the force path. Verify that the force application point is consistent.
Overload Indication: Check that the applied force does not exceed the rated capacity. Inspect the load cell for permanent deformation from past overloads.
III. Signal Conditioning
- Use appropriate excitation voltage as specified by the load cell manufacturer
- Set the signal amplifier gain to match the load cell output sensitivity
- Apply appropriate filtering to remove electrical noise while maintaining acceptable response time
