Dwyer Instruments RHPX Series - Page 5

BACnet PROTOCOL REFERENCE
The following sections explain the transmitter functions in systems employing a
BACnet protocol.
BACnet services
The RHPX Comms supports the following BACnet BIBB services and functions:
Device Communications Control-B (DM-DCC-B): Optional time duration in
minutes
Reinitialize Device (DM-RD-B): COLDSTART and WARMSTART
The password required to execute these functions is: Dwyer
Objects
This device supports the following objects:
Accessing Measurements
The analog input AI1 transmits the relative humidity measurement.
The two analog inputs AI2-AI3 transmit the dew point calculation in the desired
engineering units.
The two analog inputs AI4-AI5 transmit the enthalpy calculation in the desired
engineering units.
The two analog inputs AI6-AI7 transmit the absolute humidity measurement in
the desired engineering units.
The two analog inputs AI8-AI9 transmit the temperature measurement in the
desired engineering units.
Analog value object AV1 allows the relative humidity value to offset by up to
±3.5%.
Analog value object AV2 allows the temperature value to be offset by up to ±5°F.
I. BACnet DEVICE OBJECTS
Object Type Identier Name
Device 607XXX* RHPX 607XXX
Analog Input AI1
AI2
AI3
AI4
AI5
AI6
AI7
AI8
AI9
Relative Humidity
Dew Point degrees C
Dew Point degrees F
Enthalpy kJ/kg
Enthalpy BTU/lb
Absolute Humidity g/m
3
Absolute Humidity lb/MMCF
Temperature degrees C
Temperature degrees F
Analog Value AV1
AV2
Humidity Offset %RH
Temperature Offset deg F
Multi-State Value MSV1
MSV2
Temperature Display Unit`
Humidity Display Measurement
Network Port NP1 MS/TP
*XXX is replaced by the address value set by the address DIP switches
Property Default Values User
Writable
Data Type
Object Identier DEV607XXX Yes Object
Identier
Object Name “RHPX 607xxx” Yes Character
String(32)
Object Type Device No Object Type
System Status Operational No Device Status
Vendor Name “Dwyer Instruments, LLC” No Character
String
Vendor Identier 607 No Unsigned
Model Name “RHPX-XXXXX-XX No Character
String
Firmware Version “x.x” No Character
String
Application Software
Version
“x.x.x” No Character
String
Location “” Yes Character
String(32)
Description Humidity/Temperature
Transmitter”
Yes Character
String(32)
Protocol Version 1 No Unsigned
Protocol Revision 22 No Unsigned
Protocol Services See BACnet Services No Protocol
Services
Supported
Supported Object Types See Object Table No Object Types
Supported
Object List See Object Table No BACnetArray
of Object
Types
Maximum APDU Length 480 No Unsigned
Segmentation Supported No Segmentation No Segmentation
APDU Timeout 0 No Unsigned
Number of APDU Retries 0 No Unsigned
Max Master 127 Yes Unsigned8
Max Info Frames 1 Yes Unsigned8
Device Address Binding { } No Address
Binding
Database Revision 0 No Unsigned
Serial Number “xxxxxx” No Character
String
Multi-address support Multi-Address support allows a register to be read or
written to using different byte orientations as specied by the address range.
For example, input register 0003 can also be read at 2003, 4003 and 6003 with
different byte orientations as listed in the table below. Registers that do not have
multi-address support are only available in Big-Endian byte orientation (Modbus
®
Communication Protocol standard).
Byte Order
Address
Range
Float/32-bit Values 16-bit Values
Register 1 Register 2 Register 1
MSB LSB MSB LSB
Big-Endian
Byte swap
Word swap
Little-Endian
1-2000
2001-4000
4001-6000
6001-8000
A
B
C
D
B
A
D
C
C
D
A
B
D
C
B
A
A
B
A
B
B
A
B
A