Checks pertaining to installation
To avoid signal drift brought on by insulation degradation, make sure there is no armour layer deformation or internal magnesium oxide insulation fracture at the bend and that the sheath bending radius is within the limit (at least twice the outer diameter).
To avoid signal lag or drift brought on by inadequate heat conduction, make sure the sheath fits tightly on the inner wall of the hot runner temperature detecting hole.
Checks for connections and wiring
To rule out signal variations due by leakage arising from insulation damage during installation, remeasure the insulation resistance between the thermocouple components and the sheath, making sure it is ≥100 MΩ.
To prevent drift brought on by poor contact or electromagnetic interference, make sure the shield is consistently grounded at one end, check terminals for oxidation or looseness, and confirm that the compensation wire calibration corresponds to the type of thermocouple.
Checks for temperature controller parameters
To rule out systematic drift brought on by improper parameter values, confirm that the thermocouple calibration setting in the Husky temperature controller corresponds with the real model and that the cold-junction compensation temperature matches the actual temperature at the terminals.
To create a new compensation curve and remove drift problems brought on by a discrepancy between the previous calibration data and the new sensor, clear the old compensation parameters and recalibrate at two to three typical operating temperatures.
Verification of operations
To finish debugging and return to regular production, heat the system to the typical hot runner operating temperature and keep it there for two hours while keeping an eye on the temperature curve. Verify that there are no random spikes or unidirectional continuous drift.
This troubleshooting process was created especially for hot runner system post-installation maintenance; it makes it possible to quickly determine the underlying cause of signal drift and resolve the issue on-site without having to send the device back to the manufacturer.
