The TB7600 thermostats are also compatible with the
Honeywell PIR occupancy sensor covers. Thermostats
equipped with a PIR cover provide advanced active
occupancy logic, which will automatically switch occupancy
levels from Occupied to Unoccupied as required by local
activity being present or not. This advanced occupancy
functionality provides advantageous energy savings during
occupied hours without sacrificing occupant comfort. All
thermostats can be ordered with or without a factory installed
PIR cover.
More Information
The additional following documentation is available on http://
customer.honeywell.com:
• TB7600 Series Installation Instructions (form number 62-
2016).
• TB7600 Series with Humidity Control Installation
Instructions (form number 62-2017).
• The PIR Application Guide for TB7600 Series (form
PRODUCT OVERVIEW
number 63-4525).
The TB7600 PI thermostat family is specifically designed for
single stage and multi-stage control of heating/cooling
equipment such as rooftop and self-contained units. The
TB7600 Series are communicating thermostats with models
available in BACnet
protocols and can be easily integrated into a WEBs-AX
building automation system based on the NiagaraAX®
platform.The product features an intuitive, menu-driven, backlit LCD display, which walks users through the programming
steps, making the process extremely simple. Accurate
temperature control is achieved due to the product’s PI time
proportional control algorithm, which virtually eliminates
temperature offset associated with traditional, differentialbased thermostats.
BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
COMPATIBILITY
Honeywell TB7600 Series thermostat compatiblity information is provided in Table 1.
Table 1. TB7600 Thermostat Compatibility Information
WEBs-AX ControllerThermostats Per Controller*WEBStation-AX
WEB-2xx1263.0 or later
WEB-6xx1263.0 or later
WEB-7xx1263.5
* 128 total devices supported. One node used by controller and one for a repeater. A repeater is required if more than 64 devices
are on a bus.
TIPS AND THINGS YOU NEED TO KNOW
• Each TB7600 Seriesthermostat is delivered from the factory with the default MAC address set at 254 (referred to as the Com
Addr in the parameters at the thermostat). At this value, BACnet communication is NOT active and the device will not
participate in the token pass either. The local LED status for the communication adapter at this point is one short flash only. To
enable BACnet communication, set the local MAC address configuration property of the thermostat to any valid value from 0
to 127.
• After the initial configuration of your device and if your BAS allows you to remove objects, we suggest that you remove all the
configuration objects to prevent unnecessary polling of unused objects and to help speed up the network.
• All configuration objects are available and accessible locally from the device itself using the local configuration routine. Please
refer to the TB7600 Series (form number 62-2016) or TB7600 Series with Humidity Control (form number 62-2017) installation
instructions for details.
• In its default mode of operation, the device will automatically match its baud rate to the baud rate of the network. Automatic
baud rate detection will occur when the MS/TP communication port is initialized (on power up). If the network speed is
changed, the device will keep listening at the previously detected speed for 10 minutes before resuming auto-bauding. Repowering the devices will force right away auto-bauding.
• If the device should go off-line, the following binded thermostat parameters will be released:
• Room Temperature
• Outdoor Temperature
• Occupancy
• The BACnet Data Link layer has two key parameters: the device object name and the device object ID. The device object
name must be unique from any other BACnet device object name on the BACnet network (i.e. not just the MS/TP subnetwork). The device object ID must be unique from any other BACnet device object ID on the entire BACnet network (i.e. not
just the MS/TP sub-network).
• On models with scheduling, time synchronization can be made through a network even if the thermostat does not support the
full date. Therefore, the device cannot claim conformance to the DeviceManagement – TimeSynchronization - B (DM-TS-B)
service. The device object does not have the Local_Time or Local_Date properties.
• Programmable models (with scheduling) are intending for stand-alone applications where the thermostat may be added to the
network at a later time. Once a programmable thermostat is added to a network all schedule must be done through the
Workbench. Local control of network settings is not supported. To hide the scheduling option from the local thermostat use
one of the BIs and set to Rem NSB if a BI is not being used.
• Device Name and Device ID properties are writable in Honeywell device object. Both properties can be renamed from any
BACnet network management tool as long as the tool itself gives access to write to these properties.
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BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
WIRING GUIDELINES
Overview
Honeywell uses EIA-485 as the physical layer between their devices and supervisory controllers
For clarity we will use the term “Device” to represent any product with an active EIA-485 network connection, including Honeywell
and non-Honeywell thermostats.
Table 2. Summary of Specifications for a Honeywell EIA-485 Network
Distributed capacitanceLess than 100 pF per meter (30 pF per foot)
Maximum length per segment1200 meters (4000 feet)
PolarityPolarity sensitive
Multi-dropDaisy-chain (no T connections)
TerminationsTB7600, TB7300, and/or TB7200 Series thermostats are
installed at both ends of the MS/TP network: 120 Ohms resistor
should be installed at each end. To reduce issues with other
BACnet devices we recommended keeping like devices on the
same bus. TB7600, TB7300 and TB7200 Series thermostats can
be installed on the same bus.
1. A TB7600, TB7300, or TB7200 device is installed at one end of
the MS/TP network and another device is installed at the other
end:
Install an End-Of-Line resistor value that matches the other
device's instructions regarding the End-Of-Line resistors
2. Other devices are installed at both ends of the MS/TP network:
Follow the other device’s instructions regarding the End-Of-Line
resistors.
Maximum number of nodes per segment64 (Honeywell devices only)
Maximum number of nodes per network128
Baud rate9600, 19200, 38400, 76800 (Auto detect)
Cable Type
Honeywell recommends the use of balanced 22-24 AWG twisted pair with a characteristic impedance of 100-130 ohms,
capacitance of 30 pF/ft or lower. A braided shield is also recommended.
Impedance
A value based on the inherent conductance, resistance, capacitance and inductance that represent the impedance of an infinitely
long cable. The nominal impedance of the cable should be between 100Ωand 120Ω. However using120Ω will result in a lighter
load on the network.
Capacitance (pF/ft)
The amount of equivalent capacitive load of the cable, typically listed in a per foot basis. One of the factors limiting total cable
length is the capacitive load. Systems with long lengths benefit from using low capacitance cable (i.e. 17pF/ft or lower).
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BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
M32571
DAISY CHAIN
CONFIGURATION
BUS CONFIGURATION
STAR CONFIGURATION
EOL
NODE 2
NODE 3
NODE 4
NODE 5
SC
EOL
NODE 1
END OF LINE RESISTOR DOES
NOT COUNT AS A NODE
M32572
LEGEND
EOL: END OF LINE RESISTOR
SC: SUPERVISORY CONTROLLER
NETWORK CONFIGURATION
EIA-485 networks use a daisy chain configuration. A daisy chain means that there is only one main cable and every network
device is connected directly along its path.
Fig. 1 illustrates two improper network configurations and the proper daisy chain configuration.
Other methods of wiring an EIA-485 network may give unreliable and unpredictable results. There are no troubleshooting
methods for these types of networks. Therefore, a great deal of site experimentation may have to be done, making this a difficult
task with no guarantee of success. Honeywell will only support daisy chain configurations.
Fig. 1. Three different network configurations: star, bus, and daisy chain.
Only the daisy chain configuration is correct for an EIA-485 network.
Maximum Number of Devices
A maximum of 64 nodes is allowed on a single daisy chain segment. A node is defined as any device (controller, thermostat,
repeater) connected to the RS485 network. Terminators do not count as a node.
NOTE: Biasing is not required with this series of devices.
To determine the number of nodes on a network, add the following:
• One node for each device, including controller
• One node for each repeater on the chain
For the example in Fig. 2, we have one node for the controller, plus 4 for the thermostats, for a total of 5 nodes.
If you have more than 64 devices, then repeaters are required to extend the network.
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Fig. 2. Five nodes network example.
BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
EOL
SC
EOL
M32573
LEGEND
EOL: END OF LINE RESISTOR
R: RS485 REPEATER
SC: SUPERVISORY CONTROLLER
EOL
R
EOLEOL
R
EOLEOL
R
EOL
Maximum Cable Length
The maximum length of a chain is related to its transmission speed. The longer the chain, the slower the speed. Using proper
cable, the maximum length of an EIA-485 daisy chain is 4000-ft (1200 m). This will only work reliably for data rates up to 100,000
bps. TB7600 themostats' maximum data rate is 76,800 bps.
If you require a maximum network length of more than 4000 feet, then repeaters are required to extend the network.
EIA-485 Repeaters
If you have more than 64 devices, or require a maximum network length of more than 4000 feet, repeaters are required to extend
the network. The BASRT-B repeater by Contemporary Controls can be used if a repeater is needed. The best configuration is to
daisy chain the repeaters to the controller. From each of these repeaters, a separate daisy chain will branch off. Fig. 3
demonstrates a valid use of repeaters in an EIA-485 network.
Do not install repeaters in series, as this may result in network reliability problems. Fig. 4 demonstrates an incorrect use of a
repeater in an EIA-485 network.
Fig. 3. Correct usage – repeaters are daisy-chained to the supervisory
controller and separate daisy chains branch from each repeater.
EOL
R
EOL
EOL
M32574
DO NOT ADD
SECOND
REPEATER
IN SERIES
EOL
SC
EOL
R
LEGEND
EOL: END OF LINE RESISTOR
R: RS485 REPEATER
SC: SUPERVISORY CONTROLLER
Fig. 4. Incorrect usage – the second repeater in series may result in an unreliable system.
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BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
End Of Line (EOL) Resistors
MS/TP network must be properly terminated. For daisy chain configurations, you must install an EOL resistor at each end of the
daisy chain. Depending on your MS/TP network configuration, the resistance value of the EOL resistor may change:
• TB7600, TB7300, and/or TB7200 thermostats are installed at both ends of the MS/TP network:
120 Ohms resistor should be installed at each end.
• A TB7600, TB7300, or TB7200 device is installed at one end of the MS/TP network and another device is installed at
the other end:
Install an End-Of-Line resistor value that matches the other device’s instructions regarding its EOL resistor value;
• Other devices are installed at both ends of the MS/TP network:
Follow the other device’s instructions regarding its EOL resistor value.
NETWORK ADAPTER
The polarity of the connection to the cable is important. From one module to the other it is important that the same color wire be
connected to “plus” or “+” and the other color wire be connected to the “minus” or ”-“. Fig. 5 shows the proper MS/TP connections
and the location of the Status LED. This Status LED may help to troubleshoot network problems.
Fig. 5. Correct MS/TP connections and location of a Status LED on a BACnet module
IMPORTANT NOTE: The Ref terminal should NEVER be used to wire shields. The 2 shields from each feed of the network
connection to a thermostat should be wired together in the back of the thermostat and properly protected to prevent any
accidental connection to the ground.
The joined shield connection should then be grounded at a SINGLE point on the whole segment. More than one ground
connection to a shielded wire may induce ground loop noises and affect communication.
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BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
GLOBAL COMMAND CONTROL LEVEL
DEVICE LEVEL
BAS FRONT-END
TB7600 SERIES TSTAT
MSTP NETWORK
GLOBAL COMMANDS ALL DEVICES
(ALL THERMOSTATS)
OUTDOOR TEMPERATURE
OUTDOOR TEMPERATURE AND HVAC PLANT CURRENT MODE
BAS CURRENT ENERGY SAVINGS MODE
GLOBAL COMMANDS SPECIFIC DEVICES
(SPECIFIC AREA THERMOSTATS)
SCHEDULE
SCHEDULE AND OUTDOOR TEMPERATURE
RESTRICT SER ACCESS TO THERMOSTAT
ROOM TEMPERATURE FOR TESTING AND OVERRIDE
OUTDOOR TEMPERATURE (AV9)
SYSTEM MODE (MV13)
FAN MODE (MV15)
Table 3 shows the different possibilities with the Status LED behavior of the BACnet module.
Table 3. Status LED condition and possible solutions
Condition of the Status LEDPossible CauseSolution
BACnet communication NOT active at
default MAC address = 254
Change MAC address to another
value from 0 to 127
1 short blink
2 short blinks (no wires connected
to the module)
The BACnet module is recognized on
the thermostat and has been installed
N/A
on the right thermostat model
2 short blinks (wires connected to
the module)
2 short blinks and a longer blink
(wires connected to the module)
Right after power is applied: 2 long
blinks and then no blinking
Module is not at the same baud rate as
the network
The module has detected the presence
of a network
Polarity has been reversed at the
module
Power off and on the thermostat
N/A
Reverse polarity at the module
INTEGRATION
This section provides compatibility and programming information useful when setting up TB7600 Series thermostats on a WEBsAX building automation system.
Global Commands
The following figure shows which objects from the thermostat can be monitored and commanded from the BAS front-end.
Fig. 6. Global commands from a BAS front-end to a TB7600 series thermostat.
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BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
Typical Graphical User Interface (GUI) Objects
The following objects should be typically used in a GUI:
• Room Temperature (AV7);
• Occupied and Unoccupied Heat Setpoints (AV 42 and AV44);
• Occupied and Unoccupied Cool Setpoints (AV 43 and AV45);
• Outdoor Temperature (AV9);
• Supply Temperature (AI16) (If available);
• Occupancy Command (MV12);
• Effective Occupancy (MV34);
• System Mode RTU (MV14) or System Mode HPU (MV13);
•G Fan (BI25);
• Y1 Cool (BI26);
• Y2 Cool (BI27);
• W1 Heat (BI28);
• W2 Heat (BI29) or Reversing Valve (BI30);
• Economizer Output (AV22) (if available);
• Aux (BI24);
• DI 1 Status (BI31);
• DI 2 Status (BI 32);
• Frost Alarm (BI36) (if available);
• Filter Alarm (BI38) (if available);
• Service Alarm (BI39) (if available);
• Fan Lock Alarm (BI40) (if available)
Fig. 7. Typical GUI for a TB7605B5014B with Economizer control.
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BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
Recommended Configuration Objects
The following objects and group objects should be typically used for configuration purposes. If your BAS allows you to remove
objects from your database, Honeywell recommends removing all configuration objects once your setup is complete. This will
prevent unnecessary polling of unused objects and will help speed up the network.
• General Options 1 Group GRP 46 and its complete list of objects;
• General Options 2 Group GRP 58 and its complete list of objects;
• Programmable Model Configuration Options Group GRP 69 and its complete list of objects;
• Stages Configuration Options Group GRP 72 and its complete list of objects;
• Economizer Model Configuration Option Group GRP 76 and its complete list of objects;
• Heatpump Model Configuration Option Group GRP 81 and its complete list of objects;
• Dehumidification Model Configuration Option Group GRP 87 and its complete list of objects;
• Humidification Model Configuration Option Group GRP 94 and its complete list of objects;
Default Device Name and default Device ID
Default Device Name is set to: Model number – MAC:
• Where MAC is the current MAC address of the device.
• Where Model number is Honeywell part number.
The device name will be upgraded as soon as there is a change to the device MAC address.
• Default Device ID is set to: 76000 + MAC
• Where MAC is the current MAC address of the device.
The device ID will also be upgraded as soon as there is a change to the device’s MAC.
For example, when a TB7600B5x14B thermostat with a MAC address of 63 is connected to a network, its default Device Name
will be TB7600B5x14B-63 and its default Device ID will be 76063.
Device Name and Device ID properties are writable in Honeywell device object. Both properties can be renamed from any
BACnet network management tool as long as the tool itself can write to these properties.
Integrating Honeywell Devices on an MS/TP Network
Before doing any BACnet integration, make sure to have Honeywell PICS (Protocol Implementation Conformance Statement).
This PICS document lists all the BACnet Services and Object types supported by a device and can be found at http://
customer.honeywell.com.
The TB7600 Series does not support the COV service. COV reporting allows an object to send out notices when its PresentValue property is incremented by a pre-defined value. Since this is not supported at Honeywell end, special attention should be
given to the polling time settings at the Supervisory Controller and Workstation level when using a graphic interface or an
application program to read or write to a Honeywell object.
Graphical interfaces
For example, some graphic interface might poll every data linked to the graphic page on a COV basis. If the 3rd party device does
not support COV, the graphic interface then relies on a pre-configured polling interval, which is usually in hundredths of
milliseconds. Any device containing a monitored object could be subject to network traffic congestion if such a polling interval is
used. Honeywell strongly recommends a polling interval of 5 seconds minimum for any graphic interface. This becomes even
more critical in area graphics where a single representation might poll many devices. If proper poll rate is not respected, devices
may be reported offline by certain front end by saturating the traffic handling capacity of BACnet MS/TP without COV
subscription.
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BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
Free programmed object or loops
As for the application program, you might want to read and write any MS/TP data on an “If Once” basis or a “Do Every” loop basis
instead of reading or writing to a 3
at the Supervisory Controller’s program scan rate, which might as well be in hundredths of milliseconds. This can easily bog
down a network as single commands can be sent to all ASC devices down the MS/TP trunks every hundredth of milliseconds.
Programs writing to the devices should have a structure similar to the following:
rd
party device’s object directly in the program. Otherwise, any read or write request will occur
If Once Schedule = On then
MV11 = Occupied
End if
If Once Schedule = Off Then
MV11 = Unoccupied
End If
OR
Do Every 5 min.
If Schedule = On Then
MV11= Occupied
Else
MV11 = Unoccupied
End If
End Do
Retries and Timeouts
Another thing to look for in a BACnet integration is the Device object of the Supervisory Controller (and the Operator’s
Workstation). This object contains the 2 following required properties: Retry Timeout and Number of APDU Retries.
1. The Retry Timeout property specifies the time between re-transmissions if the acknowledgement has not been received.
When you are experiencing problems with controllers dropping off-line, increasing this value may help.
2. The Number of APDU Retries property specifies the number of times unsuccessful transmissions will be repeated. If the
receiving controller has not received the transmission successfully after this many attempts, no further attempts will be
made.
For example, if one of the thermostats does not reply to a Supervisory Controller (SC) request, and the SC’s Retry Timeout is set
to 2000 msec and the Number of APDU Retries is set to 1 (still at the SC level), then the SC will send one other request, 2 sec
later. If the MS/TP device does not reply, it will be considered Off-line by the workstation.
So having a Retry Timeout value of 10000 msec and a Number of APDU Retries property set to 3 at the SC level may prevent
device from dropping Off-line. These properties should also be changed at the Workstation level since the workstation will likely
issue requests to any MS/TP devices when the graphics are used.
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TROUBLESHOOTING
BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
Error / Trouble
Condition
Thermostat does not
come online
Possible CauseSolution
Two or more controllers have the same
MAC address.
The MS/TP network has too many devices.Do not exceed the maximum number of
Too many devices were installed without
any repeaters.
The MS/TP cable runs are brokenLocate the break and correct wiring
MS/TP connections at the module were
reversed
The thermostat does not have powerApply power to the thermostat
Modify each duplicate address to a unique
number.
devices and maximum length allowed by the
EIA-485 specifications.
Repeaters need to be installed as specified
in this document.
Respect polarity of the wires on a MS/TP
network.
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BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
APPENDIX A: BACNET OBJECTS
TB7600 SERIES PROTOCOL IMPLEMENTATION CONFORMANCE
STATEMENT (PICS)
TB7652A5x 0B, TB7652B5x 14B, TB7656B5x 14B, TB7657B5x14B and TB7652H5x0B.
Product Description
The TB76xx series BACnet communicating thermostat has been specifically designed for RTU and heatpump applications to be
monitored on a BACnet MS-TP
Supported BACnet Services
The BACnet communicating thermostat meets all requirements for designation as an Application Specific Controller (B-ASC).
The BACnet thermostat series supports the following BACnet Interoperability Building Blocks (BIBBs).
®
network.
Application ServiceDesignation
Data Sharing – Read Property - B
Data Sharing – Read Property Multiple - B
Data Sharing – Write Property - B
Device Management - Device Communication Control - B
Device Management – Dynamic Device Binding - B
Device Management – Dynamic Object Binding - B
NOTE: The thermostat does not support segmented requests or responses.
NOTE: Time synchronization can be made through a network even if the thermostat does not support the full date. Therefore,
the device cannot claim conformance to the DeviceManagement – TimeSynchronization - B (DM-TS-B) service. The
device object does not have the Local_Time or Local_Date properties.
DS-RP-B
DS-RPM-B
DS-WP-B
DM-DCC-B
DM-DDB-B
DM-DOB-B
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BACNET OBJECTS SUPPORTED
Device Objects
BACNET INTEGRATION MANUAL FOR TB7600 SERIES THERMOSTATS
Table 4. Device Objects
Object Name
TB76xxX5x14BDeviceObject_Identifier
Type and
Instance
Object PropertyThermostat Parameter
Property 75 (R,W)
Object_Name
Property 77 (R,W)
Model Name
Property 70 (R)
Firmware Revision
Property 44 (R)
Protocol Version
Property 98 (R)
Protocol Revision
Property 139 (R)
Max ADPU Length
Property 62 (R)
ADPU Timeout
Property 10 (R)
Application-SoftwareVersion
Property 12 (R)
Max_Master (R,W)Maximum master devices allowed to be part of the
MS/TP_Address
Property 1001 (R,W)
MS/TP_Baud_Rate
Property 1002 (R,W)
Unique ID number of a device on a network
Unique name of a Device on a network
Thermostat Model number
Current BACnet firmware revision used by the
thermostat
Current BACnet firmware protocol version
Default is Version 1
Current BACnet firmware protocol revision
Default is Version 2
Maximum ADPU Length accepted
Default is 244
ADPU timeout value
Default is60 000 ms
Thermostat base application software version
Default is based on current released version
network. 0 to 127, default is 127
BACnet MS-TP MAC Address. Proprietary attribute.
Default is as assigned by configuration
BACnet MS-TP Baud-Rate. Proprietary attribute.
Range is: 1 = 9.6 KBps, 2 = 19.2 KBps, 3 = 38.4 KBps, 4
= 76.8 KBps and 5 = Auto Baud Rate. Index 5 is Write
only. Reading attribute will state current Baud rate used.
Writing index 1 to 4 will fix the Baud rate to the desired
value.
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