The application function uses a differential pressure sensor, duct area, and an internal airflow controller to modulate a VAV supply damper for temperature control and ventilation purposes. The main output is an analog output (in percent) for damper position (VavSuPos) that is generated by the PID airflow controller in this AF.
NOTE:
To calculate air volume flow, this AF uses a duct area calculation, an airflow coefficient and input from a differential pressure sensor.
Main features:
- VAV supply damper modulation for temperature control and ventilation purposes
- Air volume flow setpoint calculation
- Air volume flow calculation
- Airflow coefficient calculation (air balancing logic)
- Interlocks (box coils, box fans)
- Available Status
A VAV supply cooling (VavSuCReq), supply heating (VavSuHReq) or ventilation request (VavSuVntReq) is received from the room control function and processed into an analog output signal for VAV supply damper position (VavSuPos).
Basic function: Accept request signal from associated room controller and map it to appropriate air volume flow setpoint; Compare setpoint to air volume flow in terminal box; Pass result through a device mode logic switch prior to outputting as a command to the object that controls the device.