Preparation before Calibration: Create a Class II standard thermocouple, a low-potential DC potentiometer with an accuracy of 0.02, and a dry-block furnace/thermostat bath. Confirm that all standard equipment is still within its calibration validity period.
Pre-heat the Husky thermostat and hot runner system for 30 minutes. Check that the thermocouple wire is tight and not loose, the temperature field is steady, and there are no basic hardware flaws like weak connections or short circuits.
Multi-Point Temperature Field Data Acquisition: Choose three common temperature points at 20%, 50%, and 80% of the thermocouple range. Gradually increase the temperature from low to high while keeping a stable temperature at each position for at least 30 minutes. The temperature field change should be ≤0.2℃/min.
Follow the standard-calibrated-standard forward and reverse cyclic reading procedure. Measure each temperature point at least four times, documenting both the standard thermocouple's measured temperature and the Husky thermostat's displayed temperature. Calculate the indicator inaccuracy at each temperature point.
Linear Error Parameter Configuration
To create a full-temperature-range linear compensation curve, navigate to the Husky temperature controller's "Advanced Calibration" menu and select the multi-point linear compensation parameter setting interface. Enter error correction values for three temperature points sequentially.
Confirm that the cold junction compensation settings precisely match the recorded ambient temperature at the wiring point, preventing any additional system faults caused by cold junction temperature drift.
Verification of the closed-loop system after calibration
After you've finished adjusting the parameters, run the temperature controller's PID self-tuning program to let the system adjust to the new linear compensation features and optimise the temperature control curve.
Run for 2 hours at a constant temperature, randomly choosing different temperature points from the complete temperature range for comparison testing with normal thermocouples. Confirm that temperature measurement deviation is ≤ ±1℃ across the whole temperature range, linear error is eliminated, and temperature fluctuation is ≤ ±1℃.
This calibration process is specifically designed to address the thermocouple linear error problem in Husky temperature controllers, completely resolving the pain point that single-point calibration cannot cover the nonlinear deviation across the entire temperature range, while also meeting the stringent temperature measurement accuracy requirements of hot runner precision injection moulding.
