@dataclass
class PredictiveOnOff:
setpoint: float
deadband: float
tau: float = 10.0 # lookahead horizon (seconds)
safety_high: float = 26.0
state: int = 0 # 0=OFF, 1=ON
# Exposed diagnostics for plotting/logging
last_meas: float | None = None
last_pred: float | None = None
lower_threshold: float | None = None
upper_threshold: float | None = None
def update(self, meas_filtered: float, dt: float) -> int:
''' Update the thermostat state based on the measured temperature and a prediction.
If the predicted temperature (based on current trend) is below the lower threshold
(setpoint - deadband/2), the thermostat turns ON (state=1).
If the predicted temperature is above the upper threshold (setpoint + deadband/2),
the thermostat turns OFF (state=0).
If the measured temperature exceeds the safety_high limit, the thermostat turns OFF.
meas_filtered: The current filtered/measured temperature.
dt: Time difference since last update (seconds).
Returns the current state (0=OFF, 1=ON).
'''
if meas_filtered >= self.safety_high:
self.state = 0
self._update_diag(meas_filtered, dt, meas_filtered) # pred doesn't matter here
return self.state
# Predict a short time into the future using discrete derivative
if self.last_meas is None:
T_pred = meas_filtered
else:
dTdt = (meas_filtered - self.last_meas) / dt
T_pred = meas_filtered + self.tau * dTdt
lower = self.setpoint - self.deadband / 2.0
upper = self.setpoint + self.deadband / 2.0
# Decision using predicted temperature
if T_pred < lower:
self.state = 1
elif T_pred > upper:
self.state = 0
# else: keep previous state
self._update_diag(meas_filtered, dt, T_pred, lower, upper)
return self.state
def _update_diag(self, meas: float, dt: float, T_pred: float, lower: float | None = None, upper: float | None = None):
''' Update diagnostic variables for logging/plotting.
This includes the last measured temperature, the last predicted temperature,
and the current lower and upper thresholds based on setpoint and deadband.
'''
self.last_pred = T_pred
self.last_meas = meas
if lower is None or upper is None:
lower = self.setpoint - self.deadband / 2.0
upper = self.setpoint + self.deadband / 2.0
self.lower_threshold = lower
self.upper_threshold = upper
