What are the steps for PID parameter tuning in a hot runner temperature monitoring system?

Based on the above description of hot runner temperature monitoring system calibration and PID parameter modification methodologies, the whole PID parameters tuning stages are described as follows:

Preparation: The hot runner individual zones are set to typical production temperatures. Close the mold cooling water, so that the system is steady and unloaded. Avoid the external interference, which might impact the tuning result.

Initial Parameter Setting: First, the medium value of proportional gain P , integral time Ti = 1.5*hot runner heating time, and derivative time Td = 1/4*Ti, are used to build the basic framework of the parameters.

Auto-Tuning Triggering Press and hold the "AT" button on temperature control panel for 3-5 seconds to enter into auto-tuning mode. The device will automatically carry out a number of 2-3 heating-overshoot-cooling cycles, lasting 15-30 minutes. Power should not be stopped throughout this period.

Manual fine-tuning and optimization: After auto-tuning, if the temperature overshoot is considerable, decrease P and raise Ti; if the steady-state fluctuation is large, slightly increase D to accommodate the thermal inertia of different zones.

Verification and Consolidation: Run the system for 30 minutes to verify that the temperature reaches a stable state in all areas within ±1℃ without considerable overshoot. Click Save Parameters to finish the tuning procedure.

This method is a combination of the simplicity of automatic tuning and the accuracy of manual fine tuning, and hence is applicable for most industrial hot running situations.