I. Addressing Fundamental Parameter Issues
Symptom: Repeated shifts after recalibration, linear deviation ≤0.2mm, and zero drift.
Solution: Re-perform two-point calibration, fine-tune the zero point and full-scale coefficients, and complete the linearity verification at three intermediate points after powering on and warming up the sensor for 15 minutes. This will rectify the fundamental parameter deviation.
II. Addressing Problems with Installation Structures
Symptom: The full stroke is accurate in certain sections, but the deviation exceeds the standards in others, accompanied by a slight sensation of sticking.
Solution: Adjust the sensor mounting bracket to ensure that the coaxiality is ≤0.1mm and the parallelism deviation between the probe and the hot runner plate is ≤0.5mm. Accuracy will be restored by applying a small quantity of high-temperature grease to the follower shaft, which will prevent it from sticking.
III. Addressing Signal Interference Problems
Symptom: Unstable accuracy fluctuations, small data spikes, and no fixed deviation pattern.
Methods for Troubleshooting:
Solution:
Impact: Verify that the shielded cable is consistently grounded at one end.
Incorporate a signal isolation barrier into the signal circuit.
Divert the signal cable from the power cable.
The accuracy will be stabilised by the elimination of electromagnetic interference.
Symptom: The accuracy continues to surpass the standard even after all of the aforementioned operations have been completed. This suggests that the magnetic ring has been demagnetised or that internal measuring components have been worn.
Solution:
Remagnetize/demagnetize the components and replace the worn internal brush assembly.
A comprehensive calibration of the entire range.
The accuracy will subsequently revert to the standards of the factory.
Final Solution:
It is indicative of irreversible damage to the sensor's central measuring components if the accuracy continues to fall short of the standard despite the completion of all the aforementioned steps.
Substitute with a sensor of the same model that is produced domestically and is more cost-effective.
The cost of each unit is approximately 100 RMB, which is significantly less than the time and expense associated with returning an imported sensor for repair.
This tier-based solution is optimally suited for the Hall effect displacement sensor that you have selected, which is low-cost and domestically manufactured. It can promptly address the issue of substandard accuracy following the repair and rapidly re-establish the capacity to monitor thermal expansion displacement in hot runner systems.
