Testing your PIDKiln
After assembling your ESP32Kiln, it's recommended to do some dry-run tests first. You will know immediately after powering on whether the LCD is working and whether the temperature sensor shows reasonable data.
To properly test and tune, the best approach is to use a DC-DC SSR relay (instead of the DC-AC one used in production) and hook a small halogen bulb (or old-style car bulb - not LED) directly near the thermocouple sensor.
Connect the bulb through the relay to a 12V power supply and start testing.
This setup is quite safe and easily reaches 100°C. Two small test programs are included with ESP32Kiln:
- One simulates a real program at low temperature (faster cycles)
- One does a simple up/down test - good for PID tuning and learning
Of course you can keep your normal AC SSR and use it with an old-style 100W incandescent bulb - but since it involves mains voltage, this is less safe to experiment with.
Before starting manual tuning, consider running the Calibrate function from the LCD menu. This runs the Ziegler-Nichols relay oscillation method at ~300°C and calculates initial Kp/Ki/Kd values automatically. These are saved to preferences when complete.
After auto-tune, run a test program and check the temperature trace in the web interface graph. Fine-tune from there. See PID tuning for more detail.