killee / sauna-controller Goto Github PK

That's bad. In case of hanging the device the oven is heating all the time

Hey @killee ,
I have rebuilt the setup so far. Many thanks for the great description.
However, I am currently facing the problem that when "heating=off" the voltage at the SSR is 5V and when I switch it on it drops to 1.9V - so the 5V is only present in the "off" state. Is that normal?
You wrote something about the NPN transistor, can you tell me which one you used?

Thanks in advance

I would like to contribute for those who cares in 4 steps.

T Sensor
For an experimental purpose, a used a DHT22 than switched for a 18ds20. Kept in code for the better comprehension.

T Regulator
I have used the same pid component for the regulation, but as output used the ac_dimmer component. To set up the PID values Kp, Kd, Ki please see below.

Dimmable Output
I used the ac_dimmer component because of the triac hardware. The main advantages are:

• Price 2.5 € vs 10 € for an SSR
• The on state voltage is about 0.85V versus 1.6V of an SSR. And the power dissipation is than twice lower, as well as the dissipator for it
• You manage the max voltage on it. So you can reduce the wear of the oven (see max_power parameter)
• You manage the min voltage on it. So you can avoid the high frequency oscillations due to approaching the set point

Set up PID
I referred to the file [Russian] .

1. Set Kp = 100, Kd = Ki = 0 and let the system heat
2. You will see a Temperature curve of your sensor like this
   
3. After 4-5 oscillations, calculate the values as follows and report them to the code:

• Kp = 1.2 * DeltaT
• Ki = 1.5 * Tau
• Kd = 0.2 * Tau

Here is my code
sensor:

• platform: dht
  pin: GPIO14
  temperature:
  id: sauna_temperature_sensor
  name: "Sauna temperature"
  humidity:
  name: "Sauna humidity"
  update_interval: 1s
  model: DHT22

output:

• platform: ac_dimmer
  id: dimmer1
  max_power: 0.8
  min_power: 0.2
  gate_pin: GPIO32
  zero_cross_pin:
  number: GPIO33
  mode:
  input: true
  inverted: yes

climate:

• platform: pid
  id: pid_climate
  name: "PID Sauna Controller"
  visual:
  min_temperature: 40 °C
  max_temperature: 90 °C
  temperature_step: 1 °C
  sensor: sauna_temperature_sensor
  default_target_temperature: 70°C
  heat_output: dimmer1
  control_parameters:
  kp: 1.44
  ki: 13.5
  kd: 1.8