Point Dictionary: FCU

Fan coil unit point dictionary. All points carry from the AHU dictionary (the FCU is a two-coil air handler in miniature); rat doubles as the coil entering temperature and sat as the leaving temperature for the inactive-coil leak pair (FCU-0004/FCU-0005), per the same proxy-binding note G36 makes for RTU coil temperatures. ASHRAE 223 mappings are pinned to the public-review artifact 223p-1.0.0-ppr2.1.ttl (owl:versionInfo 1.0.0-ppr.2.1; SHA-256 1f156f9938c0be430d2216e01e31bb183c438ba318d8d4a23d2f074ebcd6f573), not an inferred final 2026 release. That artifact imports QUDT 3.1.8; the quantity-kind and unit local names here were independently checked against the repository-declared QUDT 3.1.4 artifacts.

operating_state

Current AHU operating state as reported by the control sequence (host-derived integer). Recommended binding: G36 Section 5.16.14’s operating-state index OS#1-OS#5; any stable enumeration works, because the only in-library consumer (AHU-0004) counts transitions and never interprets specific values

• QUDT unit: UNITLESS

Distinct from expected_mode: that point is what the mode SHOULD be given conditions (AHU-0029 compares actuators against it); this one is what the sequence says the state IS (AHU-0004 counts how often it changes). Hosts typically read it from the BAS mode/state enum or derive it per G36 Section 5.16.14. Value-level semantics are deliberately unspecified here since only transitions are consumed; a host must simply keep the encoding stable, as any re-mapping mid-stream registers as a spurious transition. [FCU dictionary] Brick class and 223P pattern carried over (equipment-independent); for an FCU the state space is G36 s5.22’s OS#1-#4; only transitions are consumed (FCU-0001), so any stable enum binds.

fan_cmd

Final command requesting operation of this FCU fan

• 223P: EnumeratedActuatableProperty on the Fan contained by the FanCoilUnit via hasProperty

Attach brick:Start_Stop_Command to the contained brick:Fan, not the FCU/unit enable. PPR2.1 s223:FanCoilUnit requires a contained s223:Fan; g36:Fan requires this Binary-OnOff actuatable property. Bind after normal sequence ownership and interlocks.

fan_status

Independent run proof for this FCU fan

• 223P: EnumeratedObservableProperty on the Fan contained by the FanCoilUnit via hasProperty

Attach brick:Fan_On_Off_Status to the same contained brick:Fan. The PPR2.1 Binary-OnOff fan-status pattern is attested in the public G36 AHU model. Require independent current, speed/rotation, airflow, or auxiliary proof; command echo is invalid.

sat

Supply (discharge) air temperature

• 223P: Sensor observes QuantifiableObservableProperty attached to the AHU supply-air OutletConnectionPoint
• QUDT unit: DEG_C

Brick Discharge_Air_Temperature_Sensor is brick:aliasOf this class. 223P pattern verbatim from reference instance MultipleZoneAhu-sa-temp; medium comes from hasMedium on the owning ConnectionPoint. [FCU dictionary] Brick class and 223P pattern carried over (equipment-independent); doubles as the coil LEAVING temperature for FCU-0004/FCU-0005.

sat_sp

Supply air temperature setpoint

• 223P: QuantifiableActuatableProperty linked from the observed property via hasSetpoint
• QUDT unit: DEG_C

Aspect-Setpoint is inferred by the SHACL rule on QuantifiablePropertyShape when hasSetpoint targets the property; asserting it explicitly is safe but redundant under a reasoner. [FCU dictionary] Brick class and 223P pattern carried over (equipment-independent); the FCU discharge setpoint.

rat

Return air temperature

• 223P: Sensor observes QuantifiableObservableProperty at the AHU return-air InletConnectionPoint
• QUDT unit: DEG_C

Verbatim from reference instance MultipleZoneAhu-ra-temp. [FCU dictionary] Brick class and 223P pattern carried over (equipment-independent); the unit’s entering (return) air; doubles as coil ENTERING temperature for FCU-0004/FCU-0005.

htg_vlv_cmd

Heating coil valve command (0 = closed, 100 = full open)

• 223P: QuantifiableActuatableProperty on the hot-water Valve via hasProperty; Actuator actuatedByProperty this command and actuates the valve
• QUDT unit: PERCENT

Brick has no Heating_Valve_Command; attach Valve_Position_Command via isPointOf to a brick:Heating_Valve / Hot_Water_Valve (coil carries s223 hasRole Role-Heating). Provisional only for the class choice: brick:Heating_Command is the alternative if the point is abstract heating demand rather than physical valve position. 223P side verified at g36:HotWaterValveOrShape1; Binary-Position as an aspect on an analog command is counterintuitive but attested. [FCU dictionary] Brick class and 223P pattern carried over (equipment-independent); the FCU heating coil valve.

clg_vlv_cmd

Cooling coil valve command (0 = closed, 100 = full open)

• 223P: QuantifiableActuatableProperty on the chilled-water Valve via hasProperty
• QUDT unit: PERCENT

Attach via isPointOf to brick:Cooling_Valve / Chilled_Water_Valve (coil: s223 hasRole Role-Cooling). Same class-choice caveat as htg_vlv_cmd (brick:Cooling_Command for abstract demand). 223P verified at g36:ChilledWaterValveOrShape1 and instance MultipleZoneAhu-clg-coil-valve-command. [FCU dictionary] Brick class and 223P pattern carried over (equipment-independent); the FCU cooling coil valve.