Dwyer MS2-B - Manual (Page 4)

BACnet Communication Protocol Object Overview
The device supports the following objects
Device Information
The default device object identifier is 607xxx, where xxx is replaced by the MS/TP
MAC address set by the left DIP switch SW1. The object identifier value will change
as the MS/TP MAC address changes. However, if a specific object identifier is
written via BACnet Communication Protocol, then that value is stored and changes
to the MS/TP MAC address will no longer affect the object identifier. See Appendix
II for the device object property table.
Accessing the Measurements
The analog input object AI1 through AI4 are for viewing the pressure measurement
in the desired engineering units. The object property tables for these analog input
objects can be found in Appendix III.
Analog value object AV1 through AV4 are for viewing the Air Velocity or Air Flow
calculated values in the desired engineering units. The object property tables for
the analog value objects can be found in Appendix IV.
Setting the K factor and Area
There is an additional analog object value (AV5) for setting the K factor used to
calculate the velocity and air flow. The present value would be the value of the K
factor and can be set from 0 to 9.999.
For flow measurements, the area will also have to be set using analog value object
AV6. The present value would be the area in square feet. The area can be set from
0.01 to 999.99 square feet.
The object property tables for the analog value objects can be found in Appendix
IV.
From the factory, a K factor and the area are preset to be 1.000. If at any time the
user would like to default back to these values, they can disable the programmed
K factor and area mentioned above using the binary value object (BV1). The
present value of this object determines how the velocity and flow will be calculated.
When this value is ACTIVE (1), the default values for the K factor and area will be
used. If the value is INACTIVE (0), the presently set values for the K factor and area
will be used. The object property tables for the binary value objects can be found
in Appendix V.
Zero Calibration
Zero calibration can be done either with the push buttons or using BACnet
communications. Both pressure ports should either be vented to atmospheric
pressure or should have no pressure applied. When using BACnet
communications, the binary value object (BV2) will be used to signal the transmitter
to zero the reading. The present value of this object will be set to ACTIVE (1) to
initiate the re-calibration of the zero point of the sensor. The zero function will only
work if the current pressure is within ±2% of the span pressure of the previous zero.
If the current pressure is outside of this valid band, the zero function will fail and the
present value will be changed to INACTIVE (0). The zero function takes at most 10
seconds to complete. If after this time the present value remains ACTIVE (1), then
the command was executed successfully. The object property tables for the binary
value objects can be found in Appendix V.
Span Calibration
In order to adjust the span calibration, apply pressure to the ports of the transmitter
that is associated with the maximum end of the transmitter range. The binary value
object (BV3) will be used to signal the transmitter to adjust span. The present value
will be set to ACTIVE (1) to initiate the span calibration. The span calibration can
be adjusted only after setting the zero adjustment. It must be completed within 5
minutes of the last zero calibration. The span calibration command will fail until the
zero calibration is completed and the present value will be returned to INACTIVE
(0). The span function takes at most 10 seconds to complete. If after this time, the
present value remains ACTIVE (1), then the command was executed successfully.
The object property tables for the binary value objects can be found in Appendix V.
Reset factory Defaults
Present values for the zero, span, K factor, area, and Use Default K Factor can be
restored to the factory settings using the binary value object (BV4). The present
value will be set to ACTIVE (1) to initiate the factory default procedure. The factory
default takes at most 10 seconds to complete. If after this time, the present value
remains ACTIVE (1), then the command was executed successfully. The object
property tables for the binary value objects can be found in Appendix V.
BACnet Communication Protocol Services
Device Communication Control Service (DM-DCC-B)
This device supports the Device Communication Control Service BIBB. The
optional time duration in minutes is also supported. This device is configured with
a password that must be provided to successfully execute this command. The
password is “Dwyer”.
Reinitialize Device Service (DM-RD-B)
This device supports the Reinitialize Device Service BIBB. The supported device
states are COLDSTART and WARMSTART. All other states return error. This
device is configured with a password that must be provided to successfully execute
this command. The password is “Dwyer”.
LeD Status
The device provides three LEDs to indicate status and activity. The LEDs are
located to the right of the terminal block and are arranged from left to right as green,
yellow, and red. The green LED indicates communication with the pressure sensor.
This LED will flash very quickly most of the time, even without requests from the
BACnet Communication Protocol interface. The yellow LED indicates BACnet
Communication Protocol MS/TP communication addressed to this specific device.
The frequency and duration of this LED depends on the baud rate and size of
request sent. The red LED indicates error states by flashing specific error codes
periodically.
MAINTeNANCe/RePAIR
Upon final installation of the Series MS2 Differential Pressure Transmitter, no
routine maintenance is required. The Series MS2 is not field serviceable and it is
not possible to repair the unit. Field repair should not be attempted and may void
warranty.
WARRANTY/ReTURN
Refer to “Terms and Conditions of Sales” in our catalog and on our website. Contact
customer service to receive a Return Goods Authorization number before shipping
the product back for repair. Be sure to include a brief description of the problem
plus any additional application notes.
Dynamically
Creatable
No
No
No
No
Object
Type
Device
Analog Input
Analog Value
Binary Value
Dynamically
Deletable
No
No
No
No
Object
Identifier
607xxx
Al1
Al2
Al3
Al4
AV1
AV2
AV3
AV4
AV5
AV6
AV7
BV1
BV2
BV3
BV4 Object
Name
MS2 Pressure
Pressure inWC
Pressure Pascals
Pressure Kilo-Pascals
Pressure mmWC
Velocity FPM
Velocity MPS
Flow CFM
Flow CMH
Velocity K Value
Flow Area SqFt
Sensor Present
Use Default K Value
Zero
Span
Restore Factory
Pressure Values
Number of flashes
Solid On (not flashing)
1
2
3
error Description
Invalid Factory Configuration
Invalid BACnet Communication Protocol MS/TP Address
Auto Baud Configuration in progress, unit may not
respond to requests
Communication with pressure sensor failed
Changes to Max Master and Max Info frames require a power
cycle/reset to take effect. NOTICe