Vaisala GMW90 - Manual (Page 93)

Appendix A _________________________________________________________ BACnet Reference
VAISALA ________________________________________________________________________ 91
Calculated Humidity Objects
Table 31 Calculated Humidity Objects
Instance Name Description Unit
4 "Td" "Dewpoint" 62/64 (ºC/ ºF)
5 "Tdf" "Dewpoint" 62/64 (ºC/ ºF)
6 "dTd" "Dewpoint depression" 121/120 (ΔºK/ ΔºF)
7 "Tw" "Wet bulb temperature" 62/64 (ºC/ ºF)
8 "a" "Absolute humidity" 217/2000 grams-per-cubic-meter / grains-per-cubic-foot
(Vaisala defined unit)
9 "x" "Mixing ratio" 28/2001 grams-of-water-per-kilogram-dry-air / grains-of-
water-per-pound (Vaisala defined unit)
10 "h" "Enthalpy" 149/24 kilojoules-per-kilogram-dry-air / btus-per-pound-of-
dry-air
Table 32 Calculated Humidity Object Properties
Property Data type
(Application Type)
Writable
(Conformance
Code)
Value or Initial Value Persistence
Object_Identifier BACnetObjectIdentifier No (R) 00 00 00 xx (hex)
Object Type = 0,
Instance = x
See Table 31 above.
Nonvolatile
Object_Name CharacterString No (R) See Table 31 above. Nonvolatile
Object_Type BACnetObjectType
(ENUMERATED)
No (R) 0 (Analog Input) Fixed
Present_Value Real Yes
(When Oos) (R)
0.0 Volatile
Description CharacterString No (O) See table above Nonvolatile
Units BACnetEngineeringUnits
(ENUMERATED)
No (R) See table above Nonvolatile
Status_Flags BACnet Status Flags (BIT
STRING)
Yes (when OoS)
(R)
0 (FAULT == FALSE) Volatile
Reliability BACnet Reliability
(ENUMERATED)
Yes (when OoS)
(O)
0 (NO FAULT DETECTED) Volatile
Event State BACnetEventState
(ENUMERATED)
No (R) 0 (NORMAL) Volatile
Out_of_Service BOOLEAN Yes (R) 0 (FALSE) Volatile
COV_Increment Real Yes (O) NaN (COV reporting
disabled)
Nonvolatile
Table 33 Status Flags
Flag State Cause
IN_ALARM FALSE Event State equals 0 (NORMAL)
TRUE Event State not 0
FAULT FALSE Reliability equals 0 (NO FAULT DETECTED)
TRUE Reliability not 0
OVERRIDDEN FALSE Always FALSE
OUT_OF_SERVICE FALSE Present Value may NOT be written via BACnet
TRUE Present Value may be written via BACnet