I. Judgements Related to Accuracy Deviation
Zero Drift Exceeds Standard: Recalibration is required if the zero-point offset exceeds 0.05mm after 15 minutes of cold repose and is unable to return to the reference zero point after restarting.
Full-Range Linearity Deviation Exceeds Standard: Recalibration is necessary if the measured displacement at any calibration point across the full range deviates from the sensor output value by more than 0.1mm, and fine-tuning the parameters fails to correct this.
If the output value at the same displacement point deviates by more than 0.05mm during three consecutive full-stroke forward and reverse movements, measurement stability has deteriorated, necessitating recalibration. Repeatability Error Exceeds Standard.
II. Decisions Regarding Signal Anomalies
Uncontrolled Signal Jumps: If the displacement value jumps erratically with a jump amplitude exceeding 0.1mm, and the jump cannot be eliminated by checking wiring and electromagnetic interference, a recalibration is necessary to correct the signal reference.
Output Signal Offset: Recalibration is necessary if the zero-point signal deviates from 4mA by more than 0.1mA and the full-scale signal deviates from 20mA by more than 0.1mA when using a multimeter to test the 4~20mA analogue output.
III. Triggered Judgements Based on Operating Conditions: Immediate recalibration is required following a sensor's exposure to a severe mechanical impact or strong electromagnetic shock.
Sensor recalibration is necessary following the occurrence of thermal expansion lock-up or overheating in a hot runner.
Sensor recalibration is necessary to verify accuracy conformance following fault repair or core component replacement.
Recalibration is required regardless of whether accuracy is anomalous once the preset periodic calibration cycle (3~6 months under normal operating conditions) has been reached.
IV. Evaluations of Thermal Performance
The sensor must be recalibrated if the measured displacement deviates from the theoretically calculated thermal expansion value by more than 0.2mm after the hot runner has been heated to the rated operating temperature and held for 1 hour, and installation misalignment has been ruled out.
The Hall displacement sensor for hot runners that you are currently employing is entirely compatible with this set of judgement criteria, which is domestically manufactured. The judgement can be quickly completed on-site by ordinary maintenance engineers, thereby avoiding the risk of hot runner thermal expansion lock-up and unnecessary calibration downtime caused by accuracy drift or untimely calibration.
