Honeywell IAQPoint2 Guide De Démarrage Rapide page 63

Modbus
Data Flow
The IAQPoint2 can be configured to meet a variety of needs� There are up to three sensors, each
with a setpoint and fault indication� With the gas sensor, a comparison is made between the
concentration and setpoint to compute a bit� A timer responds to an occupied button� There is
a relay which can be made to respond to three possible inputs: the gas level, the fieldbus, or the
occupied timer� Most of the data is available over each of the three fieldbuses� This is shown
graphically in Figure 28� All of the fieldbus data is colored yellow�
-
Gas Sensor Value
Level
comparison
Screen Configure / Configure
+
Setpoints / Set Gas Setpoint
BACnet object GAS_SPT_AV
Modbus Hld Reg 40105
LonWorks nvi/oCO2SetPtPpm
Screen Configure / Configure
Setpoints / Set Gas Hyst
Home Screen Countdown
reset
'Occ' softkey Timer
Screen Configure / Configure
Output / Set Occupied Timeout
BACnet object RH_AI
Humidity Sensor Value
Modbus Hld Reg 40104
LonWorks nvoHVACRH
Modbus Hld Reg 40101b8
Humidity Sensor Fault
LonWorks nvo_rH_Fault
BACnet object TEMP_AI
Temperature Sensor Value
Modbus Hld Reg 40103
LonWorks nvoHVACTemp
Modbus Hld Reg 40101b4
Temperature Sensor Fault
LonWorks nvoTempFault
Figure 28. IAQPoint2 relay flow with fieldbus and simulation elements
Modbus registers
Some models of the IAQPoint2 contain a digital interface for communicating over RS-485
networks� This interface can be switched in software to use either the Modbus RTU or BACnet
MS/TP protocols� It can communicate at any speed from 4800 to 115,200 baud� When configured
for Modbus and 9600 baud, the IAQPoint2 is compatible with the Honeywell 301C controller� The
IAQPoint2 can directly replace an IAQPoint1 in Modbus or analog applications�
More information on Modbus can be obtained at www�modbus�org� The IAQPoint2 contains 12
Modbus holding registers� hese are numbered from 40101 to 40112 – it skips over the first 100�
There are no input registers, output registers, or coils� Holding registers 40101 provides a concise
summary of essential status� Two holding registers are writable via command 06�
BACnet object GAS_RDG_AI
Modbus Hld Reg 40102
LonWorks nvoCO2Ppm
LonWorks nvoCO2Percent
Modbus Hld Reg 40101b3
and
not
Gas Sensor Fault
BACnet object RLY_DRV_BO
Modbus Hld Reg 40112
LonWorks nviRelayDrive
Modbus Hld Reg 40101b0, b1
LonWorks nvoCO2Fault
Q
BACnet object OCC_DRV_BO
Modbus Hld Reg 40111
LonWorks nviDriveOccIcon
LonWorks nvisDriveOccIcon
Screen Configure / Configure
Setpoints / rH Setpoint
BACnet object Temp_SPT_AV
Modbus Hld Reg 40107
LonWorks nvi/o_rH_SetPt
Screen Configure / Configure
Setpoints / Temp Setpoint
BACnet object Temp_SPT_AV
Modbus Hld Reg 40106
LonWorks nvi/oTempSetPt
BACnet object IAQGOOD_BI
LonWorks nvoIAQGood
Screen Configure / Screen Simulate
Configure Outputs /
Set Relay
Gas Conc. Max (on)
Fieldbus Normal
Occ Tmr Min (off)
BACnet object OVDTIMER_BI
Modbus Hld Reg 40101b12
LonWorks nvoOccup
LonWorks nvoSOccup
"Occupied"
or
icon
IAQPoint2™
Relay
Coil
Modbus Hld Reg 40101b14
57