I. Preparation prior to calibration
The following tools are included in the tool list: a Grade 0 feeler gauge, a standard gauge block, a digital multimeter, host computer calibration software, and shielded electrical tools.
Prerequisites: Ensure that the sensor is powered on and has been preheated for 15 minutes. Allow the hot runner to settle to room temperature (25℃). Inspect the wiring for security and the communication link for functionality.
II. Verification of signal connection
Verify that the sensor's real-time displacement data can be displayed synchronously and normally on the host computer, without any communication interruptions or data garbling errors.
Verify the 4~20mA analogue output signal using a digital multimeter. Confirm that 0mm displacement corresponds to 4mA, full-scale displacement corresponds to 20mA, and the signal deviation is ≤0.1mA.
III. Retest of full stroke accuracy
Record the displacement data point by point, ensuring that the entire stroke is linear and free of abrupt changes or signal jumps caused by jamming, by manually pushing the hot runner plate in both forward and reverse directions in three full strokes.
Confirm that the measured displacement values at three random points are within a 0.1mm deviation from the sensor output value and that the repeatability error is less than 0.05mm by using a feeler gauge.
IV. Thermal Stability Debugging
Monitor the displacement data of the sensor output throughout the duration of one hour after the hot runner has been initiated to its rated operating temperature.
Contrast the real-time displacement values with the theoretically calculated thermal expansion values to verify that there is no numerical shift caused by temperature drift and that the deviation is less than 0.2mm..
V. Debugging the Alarm Interlock Function
Set the displacement over-limit alarm threshold to 90% of the hot runner's safe expansion clearance and manually simulate a displacement scenario that exceeds the tolerance.
Confirm that the system automatically executes the heating and deceleration actions and outputs an interlock warning signal to the hot runner temperature control system within 1 second, triggering the existing audible and visual alarms.
VI. Archiving and Final Verification
Run the hot runner continuously for 2 hours after it enters normal mass production. Ensure that the sensor monitoring data remains stable throughout, with no abnormal false alarms or missed alarms.
The entire debugging process is completed by saving all debugging parameters, generating and archiving debugging records.
The domestically produced low-cost Hall effect displacement sensor you select is fully compatible with this set of debugging procedures. The sensor can be quickly initiated and operated by ordinary maintenance engineers to guarantee that it can consistently monitor the thermal expansion displacement state of the hot runner for an extended period.
