TPI/PID is available at Thermostat over Climate?

[MBRetrofit]

As almost any gas boiler has "Thermoregulation" routine and this modulate the flame accordingly with the difference between requested temperature and room temperature ( more aggressive flame if the difference is higher - mine is has flame at minimum when the requested temp is 0,5 higher then the room temp and the boiler flame become bigger when the temperature difference is bigger and also the exterior temperature add some percentage.

As boilers does not like to be switched on/off, the VTherm can send a TPI/PID setpoint with the same algo like the one used on VTherm by Switch?

[jmcollin78]

Hello @MBRetrofit,

Central boiler can be controlled via configurable commands: https://github.com/jmcollin78/versatile_thermostat/blob/main/documentation/en/feature-central-boiler.md#configuration

So I guess, whatever how your central boiler is seen in HA, you should be able to control it.

[MBRetrofit]

Thanks, but this is for dumb thermostats/boiler that's an only can be controlled on/off. I don't know if anyone still use non "thermoregulated" or thermostats without EMODBUS, MODBUS or OPENTHERM protocols between Boiler and thermostat or between boiler and HA over ESPHome modbus.

The main advantage is that if the boiler or the modbus/opentherm thermostat is visible in HA then the only important parameter is the request and the offset. The bigger is the difference between requested temp and the room temp, the boiler through original thermostat will modulate the flame with much power.

This way, your PID algo can manipulate the temperature difference to simulate the usual on/off PID to big/small flame.

Copilot propose like this:

`class PIDController:
def init(self, kp, ki, kd, setpoint):
self.kp = kp
self.ki = ki
self.kd = kd
self.setpoint = setpoint
self.integral = 0
self.previous_error = 0

def update(self, current_temp, exterior_temp):
    # Calculate the error
    error = self.setpoint - current_temp
    
    # Proportional term
    p = self.kp * error
    
    # Integral term
    self.integral += error
    i = self.ki * self.integral
    
    # Derivative term
    derivative = error - self.previous_error
    d = self.kd * derivative
    
    # Calculate the PID output
    output = p + i + d
    
    # Adjust the output based on exterior temperature
    output += self.adjust_for_exterior_temp(exterior_temp)
    
    # Save the current error for the next derivative calculation
    self.previous_error = error
    
    return output

def adjust_for_exterior_temp(self, exterior_temp):
    # Implement your logic to adjust the output based on exterior temperature
    # For example, if exterior temperature is very low, you might want to increase the heating power
    adjustment = 0
    if exterior_temp < 0:
        adjustment = 5  # Increase output for very cold exterior temperatures
    elif exterior_temp > 30:
        adjustment = -5  # Decrease output for very hot exterior temperatures
    
    return adjustment

Example usage

if name == "main":
pid = PIDController(kp=1.0, ki=0.1, kd=0.05, setpoint=22.0)

current_temp = 20.0  # Example current temperature
exterior_temp = -5.0  # Example exterior temperature

# Update the PID controller and get the new output
output = pid.update(current_temp, exterior_temp)
print(f"PID Output: {output}") `

Explanation:
PIDController Class:

The init method initializes the PID controller with the proportional (kp), integral (ki), and derivative (kd) gains as well as the setpoint (desired temperature).
The update method calculates the PID output based on the current temperature and exterior temperature.
The adjust_for_exterior_temp method adjusts the PID output based on the exterior temperature. You can customize this method to implement your specific logic for adjusting the output based on exterior conditions.
Example Usage:

An instance of the PIDController class is created with specific PID gains and setpoint.
The update method is called with the current temperature and exterior temperature to get the new output.
Real-world Scenario:
In a real-world scenario, you would integrate this PID controller with your climate control system to continuously adjust the heating or cooling output based on the difference between the current temperature and the setpoint, while also considering the exterior temperature. The adjust_for_exterior_temp method can be further refined to implement more sophisticated adjustments based on exterior conditions.

[jmcollin78]

If I understand, you wanted to control your central boiler with a PID algorithm ?
For a PID algorithm how is the setpoint and how is defined the current room temperature ?

[MBRetrofit]

Any boiler already had a some kind of PID algorithm, the flame start strong and become smaller proportionally with room temperature coming near the requested temperature.

The Vterm just add or deduct 1 or 2 degree without taking into account this. Not to mention the 10/25 on/off feature.