VAV Damper Modulation

Briefing

A Variable Air Volume (VAV) terminal unit controls space temperature by modulating a supply-air damper and a reheat coil valve. When space temperature exceeds setpoint (cooling demand), the damper opens proportionally. When temperature falls below setpoint (heating demand), the damper returns to minimum position and the reheat valve opens proportionally. In unoccupied mode both outputs go to minimum. A FAULT_LAMP lights if sensor inputs are out of range.

Objectives

• Cooling: DAMPER_CMD = proportional(SPACE_TEMP - SETPOINT) clamped 0–100%
• Heating: DAMPER_CMD = 10% (minimum), REHEAT_VALVE_CMD proportional to (SETPOINT - SPACE_TEMP)
• OCCUPIED = FALSE forces DAMPER_CMD = 10%, REHEAT_VALVE_CMD = 0%
• FAULT_LAMP if SPACE_TEMP < -20°C or >100°C (sensor out-of-range)
• RESET_PB clears the fault latch

I/O Table

Your program will be tested against:

All test cases run automatically when you submit. Assertions are hidden until you pass.

1. #1Cooling demand opens damper proportionally

   SPACE_TEMP=25, SETPOINT=22, OCCUPIED -> DAMPER_CMD ~30%

2. #2Heating demand opens reheat, damper at minimum

   SPACE_TEMP=18, SETPOINT=22, OCCUPIED -> DAMPER_CMD=10%, REHEAT>0

3. #3Unoccupied mode sets damper to minimum

   OCCUPIED=FALSE -> DAMPER_CMD=10%, REHEAT=0

4. #4Sensor out-of-range latches FAULT_LAMP

   SPACE_TEMP=150 (out of range) -> FAULT_LAMP