I. Pre-operative Safety Preparations
Tools needed: High-precision digital multimeter, oscilloscope, standard signal generator, spare high-precision resistors/capacitors of the same specifications, anti-static wrist strap.
Safety Confirmation: Cool the hot runner system to below 60°C, disconnect the high-voltage heating output circuit of the temperature controller to avoid the risk of electric shock or accidental heating during live operation.
Reference Reference: Export the original RC parameters, filter cutoff frequency, and interference attenuation target value before drift as the reference for calibration and reset.
II. Drift Fault Location
Use a digital multimeter to directly measure the actual resistance and capacitance values of the RC network to identify the specific drifting components and distinguish between resistance and capacitance drift.
Use a standard signal generator to input standard sine waves of different frequencies to the temperature controller input terminal. Use an oscilloscope to observe the waveform at the filter output terminal, measure the current actual filter cutoff frequency and interference attenuation amplitude, and confirm the specific value of the drift exceeding the standard.
Check the surrounding environment for any newly added sources of interference or damage to the temperature sensing wires to rule out "false drift" caused by external factors.
III. Calibration and Reset Step-by-Step Operation
Small Drift Calibration: If the parameter drift deviation is ≤30%, use the temperature controller's built-in dynamic RC adjustment menu to fine-tune the resistor and capacitor input settings to calibrate the actual filter cutoff frequency back to the set value, ensuring the target interference attenuation is ≥20dB.
Hardware Drift Repair: If the component hardware drift deviation is >30%, disconnect the power, remove the drifting resistor/capacitor, replace it with a high-precision temperature drift component of the same specification, and remeasure the capacitance value after soldering to confirm that the deviation from the nominal value is ≤5%.
Parameter Reset and Lock: Enter the temperature controller's "Signal Filtering Settings" menu, restore the RC parameters to the original reference value, and re-enable the manual lock function to prevent the parameters from automatically jumping again.
IV. Post-Calibration Closed-Loop Verification
Verify using standard test signals to confirm that the total RC time constant is ≤200ms, the temperature measurement signal delay is ≤200ms, and all performance indicators return to the acceptable range.
Restore the hot runner heating loop, start the heating process, and observe the temperature control curve to confirm no jumps, no overshoot, and no oscillations.
Simulate the maximum interference conditions in the field to verify the stable filtering effect, with temperature reading fluctuations ≤±0.5℃.
Enter the RC parameters, operation time, and replaced component information after calibration reset into the process file and update it synchronously for subsequent calibration cycles.
