Kiln Controller Configuration Manual

General Settings

kiln_name:
This setting specifies the name of your kiln. It is used to identify the unit in logs, alerts, and when managing multiple kilns.
A unique and descriptive name helps with tracking performance and maintenance schedules.
Choose a name that reflects the kiln’s function or location, such as "MeltTech Alpha" or "Newcastle Kiln 1".

function_passcode:
This is a security measure to restrict access to advanced functions of the kiln controller.
It is highly recommended to change the default passcode "0000" to something more secure to prevent unauthorized modifications.
Use a mix of numbers and, if allowed by your system, symbols for a robust passcode.

profile_path & kiln_profiles_directory:
These settings define the file system locations where the kiln’s firing profiles are stored.
They must match the actual directories on your system where you keep your schedules and temperature curves.
Consistent and correct paths ensure that your kiln controller loads the correct profile during operation.

Logging Options

log_level:
Sets the verbosity of the logging output for the kiln controller.
Options range from "debug" for very detailed logs to "critical" for only the most important messages.
For normal operation, "info" is recommended; switch to "debug" when troubleshooting issues.

log_format:
Specifies the structure and content of each log entry.
A common format is %(asctime)s %(levelname)s %(name)s: %(message)s, which provides timestamps, log level, and message details.
Customizing this can help you include additional data such as module names or process IDs for better diagnostics.

Server Settings

listening_ip:
The IP address on which the kiln controller’s server will listen for incoming connections.
Default is "127.0.0.1", which limits access to the local machine.
To allow remote access, set this to the appropriate network interface IP.

listening_port:
The network port used for server communications.
Ensure that the port is not in conflict with other services and that your firewall settings allow traffic on this port.
The default value is 8081, but it can be changed as per your network configuration.

Scheduling

schedule_start:
Defines the start time for a kiln run according to a firing schedule.
The value should be a valid datetime string formatted according to your system’s expectations.
This allows for automated operation, ensuring the kiln starts at the optimal time.

Cost Information

kwh_rate:
Specifies the cost per kilowatt-hour (kWh) of energy.
This setting is used in calculations to estimate the cost of running the kiln.
Update this value regularly to reflect current energy prices in your region.

kw_elements:
Indicates the total power rating (in kW) of the kiln's heating elements.
This value directly affects energy consumption calculations and operational cost estimates.
Ensure that it accurately reflects the specifications of your heating elements.

currency_type:
Defines the symbol for your currency (e.g., "$", "€").
This is used in all cost displays and reports to ensure consistency.
Choose the symbol that best represents your local currency.

oven_kw:
Represents the overall power consumption of the oven in kilowatts.
This setting can be used in advanced energy management and forecasting calculations.
It should be updated based on measured or calculated consumption values.

PID Controller Settings

pid_kp, pid_ki, pid_kd:
These are the initial proportional, integral, and derivative gains for the PID controller.
They determine the responsiveness of the control system to temperature errors.
Fine-tune these values gradually, using autotuning if available, to achieve stable and accurate control.

stop_integral_windup:
When enabled, this feature prevents the integral term from accumulating to dangerous levels.
It stops the windup that can occur during prolonged error conditions, which might otherwise lead to overshoot.
It is critical for maintaining control stability, especially in long heating cycles.

temperature_average_samples:
Specifies the number of temperature readings used to compute an average value.
Averaging helps smooth out transient fluctuations and sensor noise.
Increase this number in noisy environments for more stable temperature readings.

pid_control_window:
Defines the acceptable error range (in °C) within which the PID controller actively adjusts the heating.
If the error is outside this window, the system may reduce corrections to avoid instability.
Adjust this based on the thermal inertia of your kiln to achieve optimal performance.

ignore_pid_until & ignore_pid_control_window_until:
These thresholds prevent the PID controller from engaging until the kiln reaches a certain temperature.
They are used to avoid aggressive control actions during startup or when the kiln is very cold.
Set these values based on your kiln’s safe operating temperature range.

throttle, throttle_below_temp, throttle_percent:
These settings are used to limit the heating power in order to prevent overshoot or reduce energy consumption.
"throttle" may define a base delay or adjustment factor, "throttle_below_temp" sets the temperature below which throttling begins, and "throttle_percent" determines the percentage reduction.
Adjust these values if you observe excessive heating or if energy conservation is a priority.

kiln_must_catch_up:
When enabled, this setting allows the kiln controller to adjust its operation to catch up to the desired temperature profile if it falls behind.
It can automatically increase output or adjust the schedule to compensate for lost heat.
Use this feature if maintaining a strict temperature curve is critical for your process.

Hardware Settings

gpio_heat & gpio_cool:
These settings specify the GPIO pins that control the kiln’s heating and cooling elements.
They must match the physical wiring of your kiln’s control circuitry.
Incorrect settings here will prevent proper control of the kiln’s output.

gpio_sensor_cs, gpio_sensor_clock, gpio_sensor_data, gpio_sensor_di:
Define the GPIO pins used by your temperature sensor (e.g., a MAX31855 thermocouple sensor).
They ensure that the controller communicates correctly with the sensor hardware.
Verify these pins with your sensor’s datasheet and your wiring diagram.

max31855:
A boolean flag indicating whether the MAX31855 sensor is in use.
Set this to true if you have the MAX31855 installed; otherwise, the controller may default to simulated sensor values.
This is critical for ensuring accurate temperature readings.

sensor_time_wait:
Specifies the delay between successive temperature readings (in seconds).
A shorter delay provides more real-time data but may introduce noise; a longer delay smooths out the readings.
Adjust this value to balance responsiveness with accuracy.

thermocouple_offset:
This value is used to calibrate the temperature sensor reading if it consistently reads too high or too low.
It allows you to fine-tune the sensor output to match a trusted thermometer.
Regular calibration is recommended to maintain accuracy over time.

output_inverted:
Determines whether the output control signal is inverted relative to the hardware requirements.
Some relay or transistor configurations require an inverted signal to function properly.
Set this based on your specific hardware setup.

service_running_led & service_running_led_gpio:
Controls a status LED that indicates whether the kiln controller is operational.
"service_running_led" enables the LED feature, and "service_running_led_gpio" specifies the GPIO pin for the LED.
This provides a quick visual confirmation of system status.

ac_freq_50hz:
Indicates whether the local AC power frequency is 50Hz. This can affect sensor readings due to interference.
Set this to true for 50Hz regions or false for 60Hz regions.
Accurate setting is important for minimizing electrical noise in sensor data.

honour_thermocouple_short_errors:
Controls whether to treat thermocouple short errors as critical faults.
If enabled, the system will abort a run when these errors are detected, protecting your kiln.
Adjust based on your sensor’s reliability and the frequency of false errors.

Compensation Settings

compensation_enabled:
Enables dynamic compensation adjustments during kiln operation.
When true, the controller will attempt to correct for heat losses or timing discrepancies in real time.
This is useful for maintaining a precise temperature curve despite environmental variations.

max_compensations:
Limits the number of compensation adjustments that can be applied during a run.
This prevents the system from making too many corrections, which can destabilize the temperature control.
Adjust this value based on the thermal characteristics of your kiln.

temp_drop_value:
The temperature (in °C) by which the target temperature is reduced during compensation cycles.
This helps prevent overshooting by gradually lowering the target when compensation is applied.
Experiment with this value to achieve a balance between energy savings and product quality.

compensation_window:
Defines the sensitivity range (in °C) within which compensation adjustments are triggered.
A narrower window means even small deviations trigger compensation, while a wider window is less sensitive.
Tune this value to match the responsiveness of your kiln and your quality requirements.

hold_time:
The duration (in seconds) for which the kiln holds a specific temperature during a compensation phase.
Longer hold times can help stabilize the process, but may extend the overall run time.
Adjust based on the kiln’s thermal mass and the required processing time.

Auto Tuning Adjustments

autotune_enabled:
Enables the auto-tuning feature, allowing the PID controller to adjust its parameters automatically.
This feature is useful for adapting to changes in the kiln’s behavior over time.
It can save you the hassle of manual tuning, especially in complex thermal environments.

autotune_hysteresis:
Defines a hysteresis range (in °C) to prevent rapid oscillation of PID adjustments during auto-tuning.
A larger hysteresis value ensures stability by reducing the frequency of tuning changes.
It is particularly useful in systems with fluctuating temperatures.

min_pid_kp, min_pid_ki, min_pid_kd:
These settings establish the minimum allowed values for the PID gains during auto-tuning.
They serve as a safety floor to ensure the controller does not tune too low, which could cause insufficient control.
Set these values conservatively to maintain stable and effective temperature regulation.

autotune_max_runtime:
Specifies the maximum time (in seconds) allowed for an auto-tuning session.
This prevents the tuning process from running indefinitely and potentially delaying kiln operation.
Adjust this based on the complexity of your system and the time needed for stable tuning.

tune_target:
The target temperature that the auto-tuning process uses as a reference.
It should represent a typical or ideal operating point for your kiln.
Ensure this temperature is within safe limits and reflects the desired firing conditions.

Automatic Restart Settings

automatic_restarts:
When enabled, the kiln controller will automatically attempt to restart a run after an unexpected shutdown or failure.
This feature helps minimize downtime and ensures that the process can resume without manual intervention.
It is recommended in environments where continuous operation is critical.

automatic_restart_window:
Defines the time window (in minutes) during which a saved state is considered valid for an automatic restart.
If the saved state is older than this window, the system will not attempt a restart using that state.
Set this value based on how quickly the kiln conditions may change between runs.

Version Information

kiln_controller_version:
This field displays the current version of the kiln controller software.
It is automatically updated with each software release and is read-only.
Keeping track of the version helps ensure you are running the latest updates and features.