Barn climate control

Description
This SCL function block, FB_ClimateControl, monitors CO₂, temperature, and humidity and controls fans and heating in automatic or manual mode. Runnable in the Siemens TIA Portal, it theoretically reliably controls indoor climate in offices, laboratories, or production areas.

Note: All modules are designed exclusively as a learning and optimization basis and are not approved for live operation. System modules, in particular, must be finally tested and commissioned by qualified personnel before productive use.

How it works

1. CO₂ monitoring: CO2Actual > CO2Limit → AlarmCO2=TRUE, StatusText=“CO₂ too high!”
2. Manu mode: ManuFan or ManuHeating=TRUE → Fan/Heating after operation, RETURN
3. Automatic fan:
   – TempActual > TempSetpoint+1 °C OR HumidityActual > HumiditySetpoint+5 % → Fan=TRUE, StatusText=“Fan on”
   – otherwise → Fan=FALSE, StatusText=“Fan off”
4. Automatic heating: TempActual < TempSetpoint−1 °C AND DoorOpen=FALSE → Heating=TRUE, StatusText=“Heating on”; otherwise Heating=FALSE

Technical details
• Inputs: CO2Actual, CO2Limit, Automatic, Manual Fan, Manual Heating, TempActual, TempSetpoint, HumidityActual, HumiditySetpoint, DoorOpen
• Outputs: AlarmCO2, Fan, Heating, StatusText (STRING)
• IF/ELSIF logic with RETURN in manual mode and in case of CO₂ alarm
• Hysteresis via target offset for temperature and humidity

Possible applications
• Room air conditioning in office and laboratory areas
• Cooling/heating support in engine rooms
• Retrofit of existing HMI climate systems to save energy
• Training demonstration of PLC-controlled climate automation

compatibility
Siemens S7-1200 & S7-1500; TIA Portal V13 and higher (V16+ recommended for PLCSIM & HMI)

Scope of delivery
.scl file with declaration of all inputs/outputs, internal variables, and header comments (version, author, email, customization notes); download link after purchase

Support
Adjustment of thresholds, integration of additional sensors or HMI layouts on request via shop message or email.