AHU Simulator
Lesson 3.4
Map the points. Wire the controller. Learn the sequence. Run the system.
Point Mapping
| Point | Category |
|---|---|
| OAT (Outside Air Temperature) | AI |
| Return_Air_T (Return Air Temperature) | AI |
| Supply Air Temp | AI |
| Dct_StatPres (Duct Static Pressure) | AI |
| OCC (Occupancy) | BI |
| OADmpr_Cmd (Outside Air Damper 0-100%) | AO |
| ChW Valve (Chilled Water Valve 0-100%) | AO |
| HW_Vlv (Hot Water Valve 0-100%) | AO |
| Fan Speed Cmd (Fan Speed Command 0-100%) | AO |
| FanEnable (Fan Enable On/Off) | BO |
Wire Sheet
Input terminals: AI1-AI4 (Analog In), BI1 (Binary In) Output terminals: AO1-AO4 (Analog Out), BO1 (Binary Out)
Sequence of Operations
OFF: System unoccupied. Fan off, all dampers closed, both valves closed, VFD at 0%.
ECONOMIZER: OAT below 65 degrees F and cooling is needed. Fan on, OA damper opens, CHW valve closed, VFD modulates for DSP.
COOLING: Cooling needed but OAT too warm for economizer. Fan on, OA damper at minimum (20%), CHW valve modulates, VFD modulates for DSP.
HEATING: Below heating setpoint. Fan on, OA damper at minimum (20%), HW valve modulates, VFD modulates for DSP.
DEADBAND: Between setpoints. Fan on, OA damper at minimum (20%), both valves closed, VFD holds DSP setpoint.