PID tuning

How to calibrate the PID temperature controller for each of the G1’s heating zones. Run this after any hardware change affecting temperature stability (new fan, different nozzle, different material airflow).

When to do it

After installing a new cooling fan or changing fan position
After replacing a heater cartridge or thermistor
When a heating zone consistently overshoots or oscillates instead of holding steady
After a major Klipper firmware update (if temperature behavior changes)
When printing in a very different ambient temperature (e.g. outdoor/cold workshop vs. heated studio)

Prerequisites

Printer powered on, G1OS dashboard accessible at http://g1os.local
Extruder clear of material (or with material loaded — both work)
Cooling fans running at the speed you use during printing (see note below)

Steps

1 — Open the Mainsail Console

Go to http://g1os.local → Console in the left sidebar.

2 — (Optional) Start the cooling fans first

If you want to calibrate with fans running, send:

M106 S128    # fans at ~50%

Adjust the value (0–255) to match your typical print fan speed.

3 — Run PID calibration for each zone

Run calibration one zone at a time. Replace TARGET with your typical printing temperature for that zone.

Feeding Zone (Extruder 0 / T0):

PID_CALIBRATE HEATER=extruder TARGET=200

Melting Zone (Extruder 1 / T1):

PID_CALIBRATE HEATER=extruder1 TARGET=220

Nozzle Zone (Extruder 2 / T2):

PID_CALIBRATE HEATER=extruder2 TARGET=220

Each calibration takes 3–8 minutes. Klipper cycles the heater on and off multiple times and computes optimal P/I/D values automatically. Wait for the message:

PID parameters: pid_Kp=... pid_Ki=... pid_Kd=...

4 — Calibrate the bed (optional)

If the bed temperature also oscillates:

PID_CALIBRATE HEATER=heater_bed TARGET=65

5 — Save the results

After all zones are calibrated:

SAVE_CONFIG

The printer restarts automatically. New PID values are written to the [extruder], [extruder1], [extruder2] sections in printer.cfg.

Verifying the result

After the printer restarts:

Heat all zones to printing temperature
Watch the temperature graph in G1OS (click the temperature display to expand)
Good PID: temperature reaches target and holds within ±2°C with no oscillation
If oscillation continues: re-run PID calibration, ensuring fans are on during calibration

Notes

The Feeding Zone (Extruder 0) tends to overshoot by 10–15°C on first heating — PID calibration corrects this
If Nozzle Zone (Extruder 2) drops 20–30°C when the fan turns on, see Heater not reaching temperature for the fan-on-sensor diagnosis first
Use the same TARGET temperature you actually print at — PID values tuned at 200°C may not be optimal at 250°C