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BAS Integration Manual
BACnet Snow/Ice
Sensor Interface 681
IS-T-681-BAS Integration

Introduction

The BACnet Snow/Ice Sensor Interface 681 communicates with a Building Automation System (BAS) using BACnet® MSTP.
This manual provides information about control parameters that can be accessed by building automation or management systems that use BACnet.

tekmar 681 BACnet Snow Ice Sensor Interface

BACnet Protocol Implementation Conformance Statement (PICS)

Vendor Name: tekmar Control Systems Ltd.
Vendor ID: 585
Product Name: BACnet Snow/Ice Sensor Interface 681
Product Model Number: 681
Application Software Version: J1297 Firmware Revision: 0.0.2 BACnet Protocol Revision: 14
Product Description:
The 681 is an interface that automatically measures the presence of snow or ice and interfaces with a
Building Automation System through BACnet to operate an automatic snow melting system.

BACNET STANDARDIZED DEVICE PROFILE

BACnet Application Specific Controller (B-ASC)

SUPPORTED BIBBS (ANNEX K) NAME
DS-RP-B Data Sharing-ReadProperty-B
DS-RPM-B Data Sharing-ReadPropertyMultiple-B
DS-WP-B Data Sharing-WriteProperty-B
DM-DDB-B Device Management-Dynamic Device Binding-B
DM-DOB-B Device Management-Dynamic Object Binding-B
DM-DCC-B Device Management-Device Communication Control-B

 

SEGMENTATION CAPABILITY SUPPORTED WINDOW SIZE
Able to transmit segmented messages No
Able to receive segmented messages No

 

STANDARD OBJECT TYPES SUPPORTED CREATABLE DELETABLE
Analog Input No No
Analog Value No No
Binary Input No No
Binary Value No No
Device No No

 

DATALINK LAYER SUPPORTED
BACnet MSTP Yes

 

NETWORK SECURITY OPTIONS
Non-secure Device

 

DATALINK LAYER OPTION SUPPORTED
BACnet MSTP Yes

 

DEVICE ADDRESS BINDING OPTION SUPPORTED
Device Address Binding NO

BACnet MSTP Connection

SERVICE NAME INITIATE EXECUTE
real property Yes
ReadPropertyMultiple Yes
DeviceCommunicationControl Yes
Who-Is Yes
I-Am Yes
Who-Has Yes
I-Have Yes

Use the 681 terminal block to connect a shielded twisted pair wire from the BACnet RS485 connection point. Wire the A, B & G conductors from the BACnet point to the 681 A, B & Ref terminals.

  • And should not be connected to the ground screws in the 681.
STATUS FLAG
In Alarm Flag F
Fault Flag F
Overridden Flag F
Out of Service Flag F/T

 

RELIABILITY
No-Fault 0
No Sensor 1
Open Loop 4
Shorted Loop 5

BACnet Analog Parameters

Analog Input Object = AI
Analog Value Object = AV
Read = R
Read/Write = R/W

OBJECT ID NAME DATA
TYPE
READ/
WRITE
STATUS
FLAG
EVENT
STATE
RELIABILITY OUT OF
SERVICE
UNITS RANGE/
VALUE
Analog Input Objects
1 Outdoor Air
Temperature
AI R FFF(F/T) Normal 0, 1, 4, 5 False or True °F (64) -76 to 266°F
2 Slab

Temperature

AI R FFF(F/T) Normal 0, 1 False or True °F (64)
3 Slab Target

Temperature

AI R FFF(F/T) Normal 0 False or True °F (64)
4 Error Code AI R FFF(F/T) Normal 0 False or True No Units(95) See Error Codes list
Analog Value Objects
1 BAS
Outdoor air temperature
AV R/W FFF(F/T) Normal False or True °F (64) -76 to 266°F
2 Melt Setpoint AV R/W FFF(F/T) Normal False or true °F (64) 32 to 95°F
3 Snow/Ice
Sensitivity
AV R/W FFF(F/T) Normal No Units

(95)

0 = Auto, 1 = Min,
2 = -2, 3 = -1, 4 = Mid, 5 = +1, 6 = +2, 7 = Max
4 Warm WeatherShut Down AV R/W FFF(F/T) Normal False or True °F (64) 32 to 95°F
5 Cold WeatherCut Off AV R/W FFF(F/T) Normal False or True °F (64) -30 to 50°F

BACnet Binary Parameters
Binary Input Object = BI
Binary Value Object = BV
Read = R
Write = W

6 NAME DATATYPE READ /

WRITE

STATUS

FLAG

EVENT

STATE

OUT OF

SERVICE

PRESENT VALUE
Binary Value Objects
1 Snow Detected BI R/W FFF/(F/T) Normal False or True 0 = False
1 = True
2 Cold Weather Cut Off BI R/W FFF(F/T) Normal False or True 0 = False
1 = True
3 Melt Pending Detected BI R/W FFF(F/T) Normal False or True 0 = False
1 = True
4 Wet Detected BI R/W FFF(F/T) Normal False or True 0 = False
1 = True
5 Sensor Mode BI R/W FFF(F/T) Normal False or True 0 = False
1 = True
6 Melt Pending Detected BI R/W FFF(F/T) Normal False or True 0 = 090 Sensor Configured
1 = 095 Sensor Configured

 

OBJECT ID NAME DATATYPE READ /
WRITE
STATUS
FLAG
EVENT
STATE
OUT OF
SERVICE
PRESENT VALUE
Binary Value Objects
1 Outdoor Sensor Enable BV R/W FFF(F/T) Normal False or True 0 = Interface measures outdoor
1 = BAS sends outdoor temperature
2 Warm Weather Shutdown Type BV R/W FFF(F/T) Normal False or True 0 = Auto, 1 = Setting
3 Cold Weather Cut
Off Type
BV R/W FFF(F/T) Normal False or True 0 = Auto, 1 = Setting
4 Reset Snow Detection Request BV R/W FFF(F/T) Normal False or True 0 = Do nothing,
1 = Reset Snow
Detection

Refer to the Installation & Operation Manual 681_D for additional information.

BACnet MSTP Troubleshooting

If there is no communication, check the following:

  • Check that the polarity on the BACnet MSTP A & B terminals is correct.
  • Check that the BACnet MSTP Ref terminal is securely connected.
  • Check that the baud rate is the same on both devices.

BACnet MSTP Specification

Communication Protocol MSTP over RS-485
Physical Layer TIA-485 two-wire plus signal ground
Baud Rate 9600, 19200, 38400, 57600, 76800, 115200 (default: 76800 bps)
Recommended Cable 18 AWG Shielded Twisted pair (STP)
Maximum Cable Length 9600 bps: 1200 meters (4000 feet) 19200 bps: 1200 meters (4000 feet) 38400 bps: 1200 meters (4000 feet) 57600 bps: 1200 meters (4000 feet) 76800 bps: 1200 meters (4000 feet) 115200 bps: 1000 meters (3280 feet)
Parity Even (1 stop bit)
Addressing 0 to 127 (default: 60)

Error Codes

CODE DESCRIPTION
1 Setpoint Menu Save Error
2 Sensors Menu Save Error
3 BAS Menu Save Error
4 Outdoor Sensor Error
5 Slab Sensor Error
6 Snow Sensor Yellow Wire Error
7 Snow Sensor Blue Wire Error
8 Snow Sensor Brown Wire Error
9 Snow Sensor Error
10 Snow/Ice Sensor

Detailed information on how to correct the error is included in the Installation & Operation Manual 681_D available at watts.com/tekmar

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S-T-681-BAS Integration 2139
Tel: 1-800-438-3903
Fax: 250-984-0815
tekmarControls.com
© 2021 tekmar

Documents / Resources

tekmar 681 BACnet Snow/Ice Sensor Interface [pdf] User Manual
681, BACnet Snow Sensor Interface, BACnet Ice Sensor Interface

References

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