63-8592 - Application Manual for T6984 & T7984 Series

63-8592

Application Manual For T6984 & T7984 Series Thermostats

Content:

1. Terms and Definition ..................................................................... 3

2. Control Sequences........................................................................ 5

3. Screw Terminals Arrangement......................................................11

4. Thermostat Dip Switch Definition ..................................................13

5. Application Notes ..........................................................................15

• PI control vs. On/Off control.................................................................................16• Modulating floating control vs. Analog 2 to 10 Vdc control ..................................17• Setpoint dial definition & setpoint limitation..........................................................18• 4 to 20 ma. output models ...................................................................................21• Installation of auxiliary screw terminals and general wiring information...............22• On/off output 2: cycle per hour dip switch setting ................................................25

6. Application Drawings For Valves ..................................................27• 2 way and 3 way valves for heating and/or cooling

7. Application Drawings For Zone Dampers .....................................41• Zone dampers• By-pass• Pressure dependent VAV• Mechanically compensated VAV

8. Checkout & Start Up Procedures ..................................................51

T6984 Product Data Manual

T7984 Product Data Manual

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1. Terms And Definitions

Changeover input

Heat/Coolchangeover ofouput 1

Models T6984E, T7984A & C all have the possibility of changeover for output 1. Automaticchangeover is used on systems were a valve or a VAV unit may have cold and hot water or air inthe same system depending on the season. Basically output 1 is primarily cooling (Direct Acting)when the changeover input is not activated. Activating the changeover input reverses thefunction of output 1 to heating mode ( Reverse Acting ) so that the thermostat can use the enddevice as a heating device instead of a cooling device.For the T6984E only a dry contact can be used for changeover.For the T7984 series a dry contact or 1 sensor per thermostat can be used for changeover.( See the Multiple & single transformer wiring application )

Mode input Models T6984D, T7984B have a mode input. These thermostat are designer to operate andfunction in 2 distinct mode of operation depending on the application requirements.This input is not a changeover input for output 1. Installing a jumper on the mode input willreverse modulating output 1 to operate as a heating only output & the on/off output 2 as acooling only output. ( see the control sequence section )

Dip switch Some thermostat have internal dip switch inside for adjustment of certain parameters.Those dip switch are accessible by removing the front cover. Be sure to familiarize yourself withwhat functions each switch represent ( See thermostat dip switch definition section )

Dip switch setting When you are familiar with the switch, be sure to select a setting that matches the applicationand the selected end devices.

End device Any peripheral component which is being controlled by the thermostat: valves, damperactuators, relays, ect........

LED All thermostat have internal service LED & a system status Led on the cover. The internalservice LED are colored lights that can be viewed from the side of the thermostat they areenergized and the system status LED is the one mounted on the cover. ( See the checkout &start up procedures section )

Modulating analog2 to 10 Vdc outputT7984 series

A type of modulating signal that uses a variable DC voltage signal. This type of output on theT7984 series uses a half wave rectifier bridge. If the same transformer is to be used for thethermostat and the end device, be sure to select end devices which also use a half wave rectifierbridge.

Modulating tri-state floatingoutputT6984 series

A type of modulating signal that uses a set of 2 contacts, one to open the end device, the otherto close the end device. This type of output uses tri-state or floating type actuators. The actuatorwill open and close to multiple position according to demand. When the demand and thetemperature is satisfied, the thermostat will stop moving the actuator and will leave to its lastposition until the demand changes again.

Motor timingdefinition T6984and modulatingfloating outputonly

It is important when using T6984 and modulating floating actuator that motor timing dip switchsetting matches the actuator being used. The motor maximum timing is the maximum runningtime that the actuator may take to complete full stroke or maximum rotation. For optimumcontrol, select a dip switch timing setting which is equal or slightly shorter than the actualmaximum running time.( 20, 30, 60, 120, 150, 240, or 420 seconds )

Night setback,day-night modeor NSB

An energy saving mode by which the actual setpoints are modified to different value than theones adjusted on the dial. The cooling setpoint will go up and the heating setpoint will go down.This mode is energized with a dry contact from a remote time clock.

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Power supply All electronic thermostat need power supply in order to work. 19/30 Vac, 50/60 Hz, 2 VABe sure to respect the polarity between each thermostat when using a common transformer.( 24 Vac & 0 Vac ) The 2 VA rating does not include the power requirement of peripheral enddevices being controlled by the thermostat.

Power upsequence

Every time power is removed and reapplied to a thermostat, it will go through a power upsequence. This sequence resets all the function of the thermostat to the desired settings. ( Seethe checkout & start up procedures section )

PTC fuse All on/off output and the open/close output ( output 1 on T6984 ) use PTC fuse for protection.These fuse are self resetting and are rated at 1.1A maximum inrush, 0.5A maximum running. Ifa short occur, remove power to the thermostat for 30 seconds to reset the fuses. Remedyproblem before putting power back to the thermostat.

On/off output An output which is normally used to control terminal reheat in a zone system. Example: electricbase board relay, electric duct heater relay, perimeter on/off 24 Vac valve, ect......

Remote sensor All thermostat have their internal sensing device ( Thermistor ) mounted internally in thethermostat. On the T6984D & E & T7984A, B & C models, it is possible to install a remote roomor remote duct return sensor at a different location than the thermostat. The remote sensor arenot to be used for supply control applications.

Output 1 Main output of the thermostat. On the T6984 series that output is a modulating floating type. Onthe T7984 series that output is analog 2 to 10 Vdc.

Triac output All reheat output and the open/close output ( output 1 on T6984 ) use electronic triac. A triac isthe equivalent of an electronic dry contact, although it has no coil or mechanical moving parts.These triac outputs are protected with self resetting fuses and are rated at 1.1A maximuminrush, 0.5A maximum running. When they are energized by the thermostat, their switchingaction is as follow:

1. The leg of the transformer being switched by the triacs is the 0 Vac leg.2. On the T6984, the common of the floating actuator being used is wired to the 24 Vac leg of

the thermostat3. On Reheat outputs, the other side of the relay or end device being used is wired to the 24

Vac leg of the thermostat

Zero energy band,deadband

On thermostats which have output 1 cooling and output 2 heating ( T6984D, T7984B&C modelsonly ), the setpoint dial definition needs to be adjusted. ( See setpoint dial definition & setpointlimitation application note )These thermostats have 2 distinct setpoints, one for heating the other for cooling ( See thecontrol curves section ). When the room temperature is between those to setpoints both heatingand cooling outputs are not working, the room temperature is in the Zero energy band. When theroom temperature drops below the heating setpoint, output 2 output will energize. When theroom temperature rises above the cooling setpoint, output 1 will energize.2 settings values are available for Zero energy band: 3°F(1.5°C) or 5°F(3°C).

Output 2On/off

Motor open

Motor close

24 Vac

( 0 Vac )

Output 1

24 Vac valve or VAVfloating actuator

24 Vac on/offrelay or valve

24 Vac transformer

Common

OpenClose

R

Power supply

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2. Control Sequences

All the control sequences and ramps are showed without any integral correction.

All the control sequences and ramps are showed in day mode operation. In night mode operation,the cooling setpoint will go up and the heating setpoint will go down.( T6984D & T7984B&C only )

The heating setpoint in night mode will go down by the NSB ( Night setback ) value.The cooling setpoint in night mode will go up by the NSU ( Night setup ) value.These values can be set using dip switch.

On model with 2 outputs, 1 in heating and the other in cooling ( T6984D & T7984B&C only ); it ispossible to adjust the value of the zero energy band ( deadband ) using dip switch.

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T6984A

T6984E

Temperature increase

Cooling mode

Heating modechangeoverinput active

50 %

SETPOINT DIAL CENTERED

OUTPUT 1 FLOATING

Opened100%

Closed0%


Cooling only mode

OUTPUT 1 FLOATING

50 %

Opened100%

Closed0%


Deviceopened

Deviceclosed

To use the thermostat ona heatingbonly application,

reverse the open/close wires

50 %


OUTPUT 1 FLOATING

Opened100%

Closed0%


Heating only mode

Deviceopened

Deviceclosed

Deviceopened

Deviceclosed

Deviceopened

Deviceclosed

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Outout 1 floating in cooling modeOutput 2 on/off output in heating mode

50 %

SETPOINT DIAL DEFINITION

100%

0%


Deviceopened

HEATINGSETPOINT

COOLINGSETPOINT

SETPOINTCENTERED

IN ZEROENERGY BAND

Deviceclosed

Deviceon

Deviceoff

ZERO ENERGY BAND

OUTPUT 1FLOATING

OUTPUT 2 ON/OFF

Mode A ( jumper not installed )

Output 1 floating in heating modeOutput 2 on/off output in cooling mode

50 %


100%

0%


Deviceopened

HEATINGSETPOINT

COOLINGSETPOINT

SETPOINTCENTERED

IN ZEROENERGY BAND

Deviceclosed

Deviceon

Deviceoff

ZERO ENERGY BAND

Mode B ( jumper installed )

OUTPUT 1FLOATING

OUTPUT 2 ON/OFF

T6984D

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T7984A


Cooling mode

Heating modechangeoverinput active

OUTPUT 1 ANALOG

50 %

Opened100%

Closed0%


Deviceopened10 Vdc

Deviceclosed2 Vdc

Deviceopened10 Vdc

Deviceclosed2 Vdc

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Output 1 analog in cooling modeOutput 2 on/off in heating mode

50 %


100%

0%


Deviceopened10 vdc

HEATINGSETPOINT

COOLINGSETPOINT

SETPOINTCENTERED

IN ZEROENERGY BAND

Deviceclosed2 Vdc

Deviceon

Deviceoff

ZERO ENERGY BAND

OUTPUT 1ANALOG

OUTPUT 2 ON/OFF

Mode A ( jumper not installed )

Output 1 analog in heating modeOutput 2 on/off in cooling mode

50 %


100%

0%


Deviceopened10 Vdc

HEATINGSETPOINT

COOLINGSETPOINT

SETPOINTCENTERED

IN ZEROENERGY BAND

Deviceclosed2 Vdc

Deviceon

Deviceoff

ZERO ENERGY BAND

Mode B ( jumper installed )

OUTPUT 1ANALOG

OUTPUT 2 ON/OFF

T7984B

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Output 1 analog in cooling modeOutput 2 analog in heating mode

50 %


100%

0%


Deviceopened10 vdc

HEATINGSETPOINT

COOLINGSETPOINT

SETPOINTCENTERED

IN ZEROENERGY BAND

Deviceclosed2 Vdc

ZERO ENERGY BAND

OUTPUT 1ANALOG

OUTPUT 2 ANALOG

Changeover inputfor output 1 not active

Output 1 analog in heating modeOutput 2 analog in heating mode

50 %


100%

0%


Deviceopened10 Vdc

HEATINGSETPOINT

COOLINGSETPOINT

SETPOINTCENTERED

IN ZEROENERGY BAND

Deviceclosed2 Vdc

ZERO ENERGY BAND

OUTPUT 1ANALOG

OUTPUT 2ANALOG

T7984C

Deviceopened10 vdc

Deviceclosed2 Vdc

Deviceopened10 Vdc

Deviceclosed2 Vdc

Changeover inputfor output 1 activated

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3. Screw Terminals Arrangement

Internal sensor

Sensor input

Mode input

NSB input

Output 2On/off

Motor open

Motor close

24 Vac

Output 1

( 0 Vac )Power supply

Internal sensor

Sensor input

Changeoverinput for Out 1

Motor open

Motor close

24 Vac

Output 1

( 0 Vac )


Motor open

Motor close

24 Vac

Output 1


( 0 Vac )

T6984A

T6984D

T6984E

T6984 Series Thermostats

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Not used

Remotesensor input

Output 12-10 Vdc

( 0 Vac )


Remotesensor input

Output 12-10 Vdc


NSB input

Output 22-10 Vdc

Remotesensor input

Output 12-10 Vdc

Mode input

NSB input

Output 2On/off

24 Vac


24 Vac( 0 Vac )


24 Vac


( 0 Vac )

T7984A

T7984B

T7984C

T7984 Series Thermostats

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4. Thermostat Dip Switch Definition

T6984 SeriesOUTPUT 2 ON/OFF CPH T6984D onlyFor more information, see on/off output cycle per hour application note.

CYCLES/HOUR S1FAST 8 CPH 1SLOW 4 CPH 0

It is possible to fix the number of time per hour the on/offoutput will be energized.

ZERO ENERGY BAND T6984D only

ZEB S25 °F ( 3 °C ) 1

3 °F ( 1.5 °C ) 0

On models which have 2 outputs, 1 for cooling and 1 forheating. It is possible to adjust the zero energy band value( dead band between heating and cooling setpoints )

SETPOINT DIAL DEFINITION T6984D onlyFor more information, see setpoint dial definition & setpoint limitation application note.

DEFINITION S3 S4 Models with cooling and heating outputs

75 °F OVERRIDE 1 1 ⇒ Setpoint dial centered, 75°F limitation not active

HEATING DIAL 0 1 ⇒ Setpoint dial defined as heating, 75°F limitation active

COOLING DIAL 1 0 ⇒ Setpoint dial defined as cooling, 75°F limitation active

CENTERED H/C 0 0 ⇒ Setpoint dial centered, 75°F limitation active

MOTOR TIME T6984A, D & E

SECONDS S5 S6 S7420 1 1 1240 0 1 1150 1 0 1120 0 0 090 0 0 160 1 1 030 0 1 020 1 0 0

Motor timing dip switch setting must matchthe used actuator maximum running time.The motor maximum timing is themaximum running time that the actuatormay take to complete full stroke ormaximum rotation. For optimum control,select a dip switch timing setting which isequal or slightly shorter than the actualmaximum running time.

DAY/NIGHT SETBACK T6984D only

HEAT SETBACK COOL SETUP S810 °F ( 5 °C ) 20 °F (10 °C ) 15 °F ( 3 °C ) 5 °F ( 3 °C ) 0

Night mode setpoints can be adjustedto different values depending on theapplication.



Deviceopened

DAY HEATINGSETPOINT

DAY COOLINGSETPOINT

SETPOINTCENTERED

IN ZEROENERGY BAND

Deviceclosed

Deviceon

Deviceoff

ZERO ENERGY BAND

OUTPUT 1FLOATING

OUTPUT 2 ON/OFF

NIGHT HEATINGSETPOINT

NIGHT COOLINGSETPOINT

HEAT SETBACK COOL SETUP

DIP SWITCH ADJUSTMENTS FOR T6984D

1 2 3 4 5 6 7 8

ON = 1

OFF = 0

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T7984 SeriesOUTPUT 2 ON/OFF CPH T7984B onlyFor more information, see on/off output cycle per hour application note.

CYCLES/HOUR S1FAST 8 CPH 1SLOW 4 CPH 0

It is possible to fix the number of time per hour the on/offoutput will be energized.

ZERO ENERGY BAND T7984B & C only

ZEB S25 °F ( 3 °C ) 1

3 °F ( 1.5 °C ) 0

On models which have 2 outputs, 1 for cooling and 1 forheating. It is possible to adjust the zero energy band value( dead band between heating and cooling setpoints )

SETPOINT DIAL DEFINITION T7984B & C onlyFor more information, see setpoint dial definition & setpoint limitation application note.

DEFINITION S3 S4 Models with cooling and heating outputs

75 °F OVERRIDE 1 1 ⇒ Setpoint dial centered, 75°F limitation not active

HEATING DIAL 0 1 ⇒ Setpoint dial defined as heating, 75°F limitation active

COOLING DIAL 1 0 ⇒ Setpoint dial defined as cooling, 75°F limitation active

CENTERED H/C 0 0 ⇒ Setpoint dial centered, 75°F limitation active

DAY/NIGHT SETBACK T7984B & C only

HEAT SETBACK COOL SETUP S510 °F ( 5 °C ) 20 °F (10 °C ) 15 °F ( 3 °C ) 5 °F ( 3 °C ) 0

Night mode setpoints can be adjustedto different values depending on theapplication.

REMOTE SENSOR T7984A, B & COn model T7984A, switch S7 & S8 are not used.

MAIN SENSOR S6LOCAL INTERNAL 1REMOTE SENSOR 0

For duct return air or remote room sensor control only. Donot use remote sensor in supply or discharge air controlapplications.

1 2 3 4 5 6

ON = 1

OFF = 0



Device100 %

DAY HEATINGSETPOINT

DAY COOLINGSETPOINT

SETPOINTCENTERED

IN ZEROENERGY BAND

Device0 %

Device100 %

Device0 %

ZERO ENERGY BAND

OUTPUT 1ANALOG

OUTPUT 2 ON/OFF OR ANALOG

NIGHT HEATINGSETPOINT

NIGHT COOLINGSETPOINT

HEAT SETBACK COOL SETUP

DIP SWITCH ADJUSTMENTS FOR T7984B & C

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5. Application Notes

5.1. PI control vs. On/Off control

5.2. Modulating floating control vs. Analog 2 to 10 Vdc control

5.3. Setpoint dial definition & setpoint limitation

5.4. 4 to 20 ma. output models

5.5. Installation of auxiliary screw terminals and general wiring information

5.6. On/off output, cycle per hour dip switch setting

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5.1. PI Control vs. On/Off Control

PI control stands for Proportional + Integral control. The T6984 & T7984 series thermostat useadvanced PI control algorithms with a small but powerful microcomputer built in the electroniccircuit board. These provide a precise temperature control and eliminate wasted heating or coolingenergy in conventional thermostats. As a result, the room occupant is able to adjust the desiredheating or cooling setpoint to is optimum comfort setting. The result is 5% to 10% energy savingwith improved comfort.

Comfort

Time

Temperature

Temperature

On/Off mechanical thermostats waste energy

PI electronic controls do not waste energy

As an analogy to PI control thermostats.

The following analogy may be useful in explaining PI Three Point Floating or PI Analog 2 to 10VDC control.

Think of the PI temperature control as a cruise control in a car, which is also a PI type control.

The damper or valve position is equivalent to: the pedal position or engine outputThe room temperature is equivalent to: the actual speed of the car

The thermostat setpoint is equivalent to: the desired cruise speed

Q. What is the position of the of the pedal when you are doing 60 MPH ?A. You don’t know and you don’t care. The pedal position will depend on such things as windspeed, fuel used, engine temperature and efficiency, the gear that the transmission is in, theincline of the road, turbulence caused by traffic, number of passenger and total load, if the airconditioning is on or not, if the windows are open, the tires used and the tire pressure and probablya million other things !

You know that the cruise control will work adequately in a variety of situations, although sometimesresulting in very small control errors when things are changing ( under dynamic conditions ). If all isconstant you may notice that the pedal position is constant.

Any variation in the actual load on the engine due to a variation of any parameter will causethe cruise control to readjust its output to maintain its desired setpoint.

Any residual error after readjustment is corrected by the integral action only.

The floating & Analog 2 to 10 VDC PI controls will provide precise control of room temperature andmaintain setpoint more accurately.

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5.2. Modulating Floating Control T6984vs.

Analog 2 To 10 VDC Control T7984

Both T6984 & T7984 series thermostat use PI control and will fully modulate end devices. Bothtype of output are able to position the end device according to the actual demand from their PIcontrol loop.

Q. Is one better than the other ?A. No both are fully modulating, although one or the other is more recommended in certain cases.

The PI floating controls will provide precise control of room temperature with lower costthree point floating motorized valve and damper actuators.

Use analog 2 to 10 VDC control when Use floating control whenYou are controlling more than 1 valve or damper

actuatorYou are controlling only 1 valve or damper

actuatorWhen you are using spring return end devices When you are using end devices with no fail

safeWhen the total installed cost needs to be lower

When you are using large end devices When you are using small end devicesWhen you are less familiar with electronic

controls ( at first, they are easier to start-up andtroubleshoot )

When you are more familiar with electroniccontrols ***

*** It is important when starting-up and commissioning T6984 thermostats series that usesmodulating floating control to properly setup the actuator direction or rotation versus the thermostatopen/close direction of rotation.

Open contact on the thermostat Close contact on the thermostatNeeds to open the end device when activated Needs to close the end device when activated

If the rotation is reversed, the controls will not work properly.

If the rotation is reversed, reverse the Open/Close wiring or flip the Left/Right switch on theactuator if it is equipped with one.

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5.3. Setpoint Dial Definition & Setpoint Limitation

Valid for these model only: T6984D & T7984B,C

Setpoint dial definition:

On thermostats which have output 1 in cooling mode and a output 2 in heating mode or vice versa.

The setpoint dial definition needs to be adjusted. These thermostats have 2 distinct setpoints, onefor heating the other for cooling ( See the control curves section ). When the room temperature isbetween those to AM both heating and cooling outputs are not working, the room temperature is inthe Zero energy band. When the room temperature drops below the heating setpoint, the Reheatoutput will energize. When the room temperature rises above below the cooling setpoint, Stage 1will energize. 2 settings values are available for Zero energy band: 3°F(1.5°C) or 5°F(3°C).

Q. On applications that have a different heating setpoint and cooling setpoint with a zero energyband, how do you define thermostat dial on the cover of the thermostat ?A. You need to set the proper dip switch to define the dial.

50 %

SETPOINT DIAL DEFINED AS CENTERED

100%

0%

Deviceopened

TRUE HEATINGSETPOINT

TRUE COOLINGSETPOINT

DIALSETPOINTCENTEREDIN ZERO

ENERGY BAND

Deviceclosed

ZERO ENERGY BAND

STAGE 1REHEAT OUTPUT

Deviceoff

Deviceoff

50 %

SETPOINT DIAL DEFINED AS HEATING

100%

0%

Deviceopened

TRUE DIAL HEATINGSETPOINT


Deviceclosed

ZERO ENERGY BAND


Deviceoff

Deviceoff

50 %

SETPOINT DIAL DEFINED AS COOLING

100%

0%

Deviceopened


TRUE DIAL COOLINGSETPOINT

Deviceclosed

ZERO ENERGY BAND


Deviceoff

Deviceoff

19 63-8592

Setpoint limitation:

On thermostats which have Stage 1 ( cooling output ) and a Reheat output ( heating output ) Thesetpoints can be limited electronically. These thermostats have 2 distinct setpoints, one for heatingthe other for cooling.

These model only: T6984D & T7984B,C series thermostat feature a setpoint limitation which iscompatible with ASHRAE 90.1

Both setpoints are electronically limited to 75°F ( 24°C ). The cooling setpoint cannot belowered below 75°F and the heating setpoint cannot be raise above 75°F.

OUTPUT1



ZERO ENERGY BAND

OUTPUT 2

Device0 %

Device100%



ZERO ENERGY BAND

OUTPUT 1OUTPUT 2

SETPOINT DIAL TURNED TO ITS LOWEST VALUE

SETPOINT DIAL TURNED TO ITS HIGHEST VALUE

COOLING SETPOINT CANNOT BE LOWER

THAN 75F

HEATING SETPOINT CANNOT BE HIGHER

THAN 75F

HEATING CENTERED COOLING

HEATING CENTERED COOLING

MINIMUM COOLING SETPOINT

IS DIAL MAXIMUM SETTING

MINIMUM HEATING SETPOINT

IS DIAL MINIMUM SETTING

TRUE HEATING AND COOLING SETPOINTS ARE ELECTRONICALLYLIMITED AT 75F WHEN DIAL IS ROTATED LEFT TO RIGHT

Device0 %

Device100%

Device100%

Device0 %

Device0 %

Device100%

63-8592 20

This setpoint limitation can be overridden for system checkout by setting the dip switch to thefollowing: T6984D & T7984B,C set S=1 & S4=1. By doing this, the setpoint dial definition is nowcentered in the middle of the zero energy band.

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5.4. 4 To 20 ma. Output

Valid for these model only: T7984A1040, T7984B1048 & T7984C1046.

1. Wiring:

0 Vac common

4-20 mA output

using a 500 Ohms 1/4 watt 5% resistor

+

-

Shunt resistor value to convert 4 to 20 mA

back to a 2 to 10 Vdc control signal

+

-

4 to 20 mAdevice

+

-

OR

+

-

2 to 10 Vdc

2. Characteristics of 4 to 20 ma output is: maximum load 500 Ω at 20 ma. Voltage source is thenaround 10 VDC. Normal load should be between 1 Ω and 500 Ω.

3. mA. signal can go as high as 25 mA du to normal component tolerance. 4. Analog voltage 2 to 10 VDC is also available for output 1 on another screw terminal but should

not be used simultaneously as the 4 to 20 mA output . Use either the 4 to 20 mA output orthe 2 to 10 VDC output, but not both.

Notes for model T7984C1046 only having the 4 to 20 mA output.

• Analog voltage 0 to 10 VDC is also available for output 1 and output 2. Only 1 of these outputcan be selected to work as the 4 to 20 mA output . Selection is done with dip switches.

Switch settings Output 1 Output 2 Dip switch #7 off Dip switch #8 off

Analog 2 to 10 VDC Analog 2 to 10 VDC

Dip switch #7 on Dip switch #8 off

4 to 20 mA Do not use and wire Stage 1 2 to 10 VDC screw terminal

Analog 2 to 10 VDC

Dip switch #7 off Dip switch #8 on

Analog 2 to 10 VDC 4 to 20 mA Do not use and wire Reheat stage

2 to 10 VDC screw terminal Dip switch #7 on Dip switch #8 on

Never set the dip switches to this setting

• Analog voltage 2 to 10 VDC is also available for output 1 and output 2 when they are

configured as 4 to 20 mA output. They should not be used simultaneously as the 4 to 20 mAoutput. Use either the selected 4 to 20 mA output or the 2 to 10 VDC output, but not both.

63-8592 22

5.5. Installation Of Auxiliary Screw Terminals And General Wiring Information

Auxiliary screw terminals: Usage of auxiliary screw terminals strip in a junction box in the ceiling is recommended whenmultiple wires are brought down at the thermostat. This is recommended for the following reasons:

• It makes troubleshooting, startup and servicing easier.• Sometime the common & 24 Vac wires are used more

than once.• It brings down to the thermostat only 1 wire instead of

3 or 4. Junctions are easier to make at larger junctionscrew terminals than at the smaller ones on thethermostats.

• Looping the same power supply, NSB contact and/orchangeover contact from thermostat to thermostat is alot easier.

General wiring information:

• Always read the instruction manuals of all componentsinstalled in the system.

• Always make a wiring diagram of the installation you want to make before starting to wire thecomponents.

• All electronic thermostat need power supply in order to work. 19/30 Vac, 50/60 Hz, 2 VA Be sure to respect the polarity between each thermostat when using a common transformer. (24 Vac & Common ) The 2 VA rating does not include the power requirement of peripheral enddevices being controlled by the thermostat.

• Never go above the rating of the triac outputs: 1.1A maximum inrush, 0.5A maximum running.

• Polarity must also be respected between a T7984 series thermostat and the analog 2 to 10VDC end device it its controlling.

• It is important when starting-up and commissioning T6984 thermostats series that usesmodulating floating control to properly setup the actuator direction or rotation versus thethermostat open/close direction of rotation.

• For changeover application using sensors on T7984 models. 1 sensor per thermostat must beused.

24 Vac transformer

L

N

NSB contact

R

A

B

2 to 10 Vdc 24 Vac &NSB contact

to other thermostats

2363-8592

24 Vac transformer

L

N

Honeywell

WIRING1 Feb 98 Rev.1

NSB contact

Changeover contact

24 Vac

Common

NSB input

Changeover input

24 Vac

Common

NSB input

Changeover input

24 Vac

Common

NSB input

Changeover input To other thermostats

Single transformer applicationA

B

Auxiliary screw terminals arrangementSingle transformer arrangement

For changeover application using sensors on T7984 models,1 sensor per thermostat must be used.

Only central NSB contact or changeover contact can be used if necessary.

Do not ground any commonleg of any transformer to earth to prevent ground loop.

Usage of auxiliary screw terminals strip in a junction box is recommendedwhen multiple wires are brought down at the thermostat. This maketroubleshooting, startup and servicing easier.

63-859224

Honeywell

WIRNG1 March 97 Rev.0

To other thermostats

24 Vac transformer 24 Vac transformer

LN

24 Vac transformer

LN

24 Vac

Common

NSB input

Changeover input

24 Vac

Common

NSB input

Changeover input

24 Vac

Common

NSB input

Changeover input

LN

AB AB AB

NSB contact

Changeover contact

Multiple transformer application

Auxiliary screw terminals arrangementMultiple transformer arrangement

For changeover application using sensors on T7984 models,1 sensor per thermostat must be used.

Only central NSB contact or changeover contact can be usedif necessary.

Usage of auxiliary screw terminals strip in a junction box is recommended when multiple wires are brought down at the thermostat.This make troubleshooting, startup and servicing easier.

25 63-8592

5.6. On/off output, cycle per hour dip switch setting

Valid for these model only: T6984D & T7984B

It is possible to fix the number of time per hour the reheat end device will be energized. Thosesetting are adjusted with dip switch.

2 different settings are possible:4 cycles per hour or 8 cycles per hour

Use the following setting for the following reheat device applications:

4 cycles per hour 8 cycles per hourAnything using a gas fired or oil fired terminalreheat device ( Never use 8 cycles per hour )

N.C. 24 Vac thermal valve( Hot wax thermal body valve )

Any gear driven end device valve or damperactuator

Properly sized electric base board strip Oversized capacity electric base board stripProperly sized electric duct heater Oversized capacity electric duct heater

If possible, always use the 4 cycles per hour setting. This setting increases the life span of the enddevice by lowering the number of annual cycles.

63-8592 26

27 63-8592

6. Application Drawings For Valves2 way and 3 way valves actuator

combinations for heating and/or coolingDrawingnumber

Valve: output 1modulating

floating control

Changeover ofvalve

(output 1) toheating mode

Output 2On/off

Nightsetback( NSB )

Optionnal remotesensor ( not forsupply controlapplications )

Thermostatmodel

number

T6984 THERMOSTAT SERIES: VALVE APPLICATIONSTO USE WITH VALVE ACTUATORS: VC6900 Series, VC6831 ( end switch model family ),

M6410, ML6161 & ML684

HWV100 Cooling orheating only

T6984A


X ( optionnal ) T6984E

HWV141 Cooling &heating →

Using a drycontact

X ( optionnal ) T6984E

HWV150 Cooling only On/off heatingonly

X X ( optionnal ) T6984D

HWV170 Heating only On/off coolingonly

X X ( optionnal ) T6984D

Drawingnumber

Valve: output 1Modulating 2 to10 Vdc control

Changeover ofvalve

( output 1 ) toheating mode

Output 2T7984Bon/off

T7984Canalog

Nightsetback( NSB )

Optionnal remotesensor ( not forsupply controlapplications )

Thermostatmodel

number

T7984 THERMOSTAT SERIES: VALVE APPLICATIONSTO USE WITH VALVE ACTUATORS: VC7900 Series, ML7984, M7410E & ML7161


X ( optionnal ) T7984A


Using a drycontact or

sensor

X ( optionnal ) T7984A

HWV250 Cooling only On/off heatingonly

X X ( optionnal ) T7984B

HWV270 Heating only On/off coolingonly

X X ( optionnal ) T7984B


Using a drycontact or

sensor

Analogheating only

X X ( optionnal ) T7984C

HWV282 Analog coolingonly

Analogheating only


HWV284 Analog coolingonly

Analogheating only


63-8592 28

24 Vac transformer

L

N

0 Vac

24 Vac

T6984A

HWV100 February 98 Rev.1

OpenOutput 1

Close

Floating valve actuator cooling

A

B

Sequence of operation for cooling:

Normal cooling mode, cold water supply

On a rise of temperature from setpoint1- Valve opens

On a drop of temperature from setpoint1- Valve closes

COOLING APPLICATION2 Way or 3 way valve

Modulating floatingvalve actuatorOpenCommon Close

For a heating only application:

Reverse open/close wires as shown

24 Vac

OpenOutput 1

Close

Common

Open

Close

29 63-8592

24 Vac transformer

L

N

0 Vac

24 Vac

T6984E


OpenOutput 1

Close

Floating valve actuator cooling

A

B







0 Vac

or

Remote room or remote duct return sensor

Important: Not for duct supply control applications

Important:When remote sensor is not used, leave factory wire jumper installedWhen remote sensor is used, remove factory wire jumperand connect sensor as shown

Sensor input

Internal sensor

Remove factorywire jumper


Install a jumper as shown

0 Vac


63-8592 30

24 Vac transformer

L

N

0 Vac

24 Vac

T6984E


OpenOutput 1

Close

Floating valve actuator coolingc/w heating changeover

A

B

COOLING & HEATING APPLICATIONc/w Changeover

2 Way or 3 way valve


0 Vac

or




Sensor input

Internal sensor


Sequence of operation:




Changeover activatedHeating mode, hot water supply

On a rise of temperature from setpoint1- Valve closes

On a drop of temperature from setpoint1- Valve opens

Changeover contact


31 63-8592

24 Vac transformer

L

N

0 Vac

24 Vac

T6984D


OpenOutput 1

Close

A

B




On a drop of temperature from setpoint1- Valve closes2- Reheat energizes



0 Vac

or




Sensor input

Internal sensor


Floating valve actuator coolingNight setback & on/off reheat

REHEAT OUTPUT DEVICES

R

R

Electric duct heater24 Vac relay without transformer

Perimeter hot water coil24 Vac 2 position N.C. valve

Hot water coil24 Vac 2 position N.C. valve

Electric base board24 Vac relay without transformer

NSB input

NSB contact

Output 2on/off

63-8592 32

24 Vac transformer

L

N

0 Vac

24 Vac

T6984D


OpenOutput 1

Close

A

B


On a rise of temperature from setpoint1- DX cooling stage starts

On a drop of temperature from setpoint1- Heating valve opens

HEATING2 Way or 3 way valve


0 Vac

or




Sensor input

Internal sensor


Floating valve actuator heatingNight setback & on/off cooling

NSB input

NSB contact

0 Vac

Mode input

Mode jumperinstalled

DX

COOLINGOn/off DX stage

Output 2on/off

24 Vacinterface

relayR

33 63-8592

24 Vac transformer

L

N

T7984A


2 to 10 Vdc valve actuator cooling

A

B






Modulating 2 to 10 Vdcvalve actuator


Install a jumper as shown

0 Vac


0 Vac or



Important:When remote sensor is not used, set dip switch #6 to position 1When remote sensor is used, set dip switch #6 to position 0

Remotesensor input

24 VacCommon Input2-10 Vdc

0 Vac

24 Vac

Output 12-10 Vdc

63-8592 34

T7984A


2 to 10 Vdc valve actuator coolingc/w changeover




0 Vac or




Remotesensor input

Modulating 2 to 10 Vdcvalve actuator24 VacCommon Input

2-10 Vdc

0 Vac

24 Vac

Output 12-10 Vdc







On a drop of temperature from setpoint1- Valve opens

Changeover contactor

Changeover sensor

24 Vac transformer

L

N

A

B

35 63-8592

T7984B


2 to 10 Vdc valve actuator coolingNight setback & on/off reheat


0 Vac or




Remotesensor input


2-10 Vdc

0 Vac

24 Vac

Output 12-10 Vdc





24 Vac transformer

L

N

A

B


Output 2on/off

NSB input

NSB contact

R

R





63-8592 36

T7984B


2 to 10 Vdc valve actuator heatingNight setback & on/off cooling

HEATING2 Way or 3 way valve

0 Vac or




Remotesensor input


2-10 Vdc

24 Vac

Output 12-10 Vdc

24 Vac transformer

L

N

A

B

Output 2on/off

NSB input

NSB contact


On a rise of temperature from setpoint1- DX cooling stage starts


DX

COOLINGOn/off DX stage

24 Vacinterface

relayR

Mode input

Mode jumperinstalled

0 Vac

0 Vac

37 63-8592

T7984C


2 to 10 Vdc valve actuator coolingc/w changeoverNight setback & modulating reheat




0 Vac or




Remotesensor input


2-10 Vdc

0 Vac

24 Vac

Output 12-10 Vdc







On a drop of temperature from setpoint1- Valve opens2- Reheat energizes


Changeover sensor

24 Vac transformer

L

N

A

B


SCRPower Control

Electric base boardModulating 2 to 10 Vdc SCR

Perimeter hot water coilModulating 2 to 10 Vdc valve

Hot water coilModulating 2 to 10 Vdc valve

Output 22-10 Vdc

NSB input

NSB contact

63-8592 38

T7984C


2 to 10 Vdc valve actuator coolingNight setback & modulating reheat


0 Vac or




Remotesensor input


2-10 Vdc

0 Vac

24 Vac

Output 12-10 Vdc





24 Vac transformer

L

N

A

B


SCRPower Control




Output 22-10 Vdc

NSB input

NSB contact

39 63-8592

T7984C


2 to 10 Vdc valve actuator cooling2 to 10 Vdc valve actuator heatingNight setback

COOLING VALVE2 Way or 3 way valve

0 Vac or




Remotesensor input

0 Vac

24 Vac

Output 12-10 Vdc



On a rise of temperature from setpoint1- Cooling valve opens


24 Vac transformer

Output 22-10 Vdc

NSB input

NSB contact

HEATING VALVE2 Way or 3 way valve

A

B

L

N


2-10 Vdc


2-10 Vdc

63-8592 40

41 63-8592

7. Application Drawings For Boxes:

Zone dampers, By-pass, Pressure dependent VAV & MechanicallyCompensated VAV

Drawingnumber

Box: output 1modulating

floating control

Changeover ofBox


Output 2On/off

Nightsetback( NSB )

Optionalremote

sensor ( notfor supply

controlapplications )

Thermostatmodel

number

T6984 THERMOSTAT SERIES: ZONE DAMPER APPLICATIONSTO USE WITH VAV ACTUATORS: ML6161

HWB100 Cooling only T6984AHWB111 Cooling only X ( optional ) T6984EHWB141 Cooling & heating

→Using a dry

contactX ( optional ) T6984E

HWB172 Cooling only Heating only X X ( optional ) T6984D

Drawingnumber

Box: output 1Modulating 2 to10 Vdc control

Changeover ofbox


Output 2T7984B on/offT7984C analog

Nightsetback( NSB )

Optionalremote

sensor ( notfor supply

controlapplications )

Thermostatmodel

number

T7984 THERMOSTAT SERIES: ZONE DAMPER APPLICATIONSTO USE WITH VAV ACTUATORS: ML7161

HWB210 Cooling only X ( optional ) T7984AHWB240 Cooling & heating

→Using a dry

contact or sensorX ( optional ) T7984A

HWB272 Cooling only On/off heatingonly

X X ( optional ) T7984B

HWB282 Cooling only Analog heatingonly

X X ( optional ) T7984C

HWB280 Cooling & heating→

Using a drycontact or sensor

Analog heatingonly

X X ( optional ) T7984C

63-8592 42

24 Vac transformer

L

N

0 Vac

24 Vac

T6984A

HWB100 February 98 Rev.1

OpenOutput 1

Close

Floating actuator cooling

A

B


Normal cooling mode, cold air supply

On a rise of temperature from setpoint1- Box opens

On a drop of temperature from setpoint1- Box closes

COOLING APPLICATIONZone damper

Modulating floatingVAV actuatorOpenCommon Close

43 63-8592

24 Vac transformer

L

N

0 Vac

24 Vac

T6984E


OpenOutput 1

Close

Floating actuator cooling

A

B






Modulating floatingVAV actuator

0 Vac

or




Sensor input

OpenCommon Close

Internal sensor


factory wire jumper installed

63-8592 44

24 Vac transformer

L

N

0 Vac

24 Vac

T6984E


OpenOutput 1

Close

Floating actuator coolingc/w changeover


0 Vac

or


Sensor input

OpenCommon Close

Internal sensor






Changeover activatedHeating mode, hot air supply

On a rise of temperature from setpoint1- Box closes

On a drop of temperature from setpoint1- Box opens

COOLING & HEATING APPLICATIONc/w Changeover Zone damper

Changeover contact


A

B



45 63-8592

24 Vac transformer

L

N

0 Vac

24 Vac

T6984D


OpenOutput 1

Close

Floating actuator coolingNight setback & on/off reheat

A

B

NSB input

NSB contact


Output 2on/off




On a drop of temperature from setpoint1- Box closes2- Reheat energizes



R

R





0 Vac

or


Sensor input

OpenCommon Close

Internal sensor




63-8592 46

24 Vac transformer

L

N

0 Vac

24 Vac

T7984A


Output 12-10 Vdc

Analog 2-10 Vdc actuator cooling

A

B






Modulating 2 to 10 VdcVAV actuator24 VacCommon Input

2-10 Vdc

0 Vac or




Remotesensor input

47 63-8592

24 Vac transformer

L

N

0 Vac

24 Vac

T7984A


Output 12-10 Vdc

Analog 2-10 Vdc actuator coolingc/w changeover

A

B







On a drop of temperature from setpoint1- Box opens



2-10 Vdc


Changeover sensor


0 Vac or




Remotesensor input

63-8592 48

24 Vac transformer

L

N

0 Vac

24 Vac

T7984B


Output 12-10 Vdc

Analog 2-10 Vdc actuator coolingNight setback & on/off reheat

A

B

NSB input

NSB contact


Output 2on/off







2-10 Vdc

R

R





0 Vac or




Remotesensor input

49 63-8592

24 Vac transformer

L

N

0 Vac

24 Vac

T7984C


Output 12-10 Vdc

Analog 2-10 Vdc actuator coolingc/w changeoverNight setback & modulating reheat

A

B

NSB input


SCRPower Control




Output 22-10 Vdc







On a drop of temperature from setpoint1- Box opens2- Reheat energizes



2-10 Vdc

NSB contactChangeover contact

orChangeover sensor


0 Vac or




Remotesensor input

63-8592 50

24 Vac transformer

L

N

0 Vac

24 Vac

T7984C


Output 12-10 Vdc

Analog 2-10 Vdc actuator coolingNight setback & modulating reheat

A

B

NSB input

NSB contact


SCRPower Control




Output 22-10 Vdc







2-10 Vdc

0 Vac or




Remotesensor input

51 63-8592

8. Checkout & Start Up Procedures

Electronic thermostats require special care for wiring and startup. To avoid problems, carefully follow theenclosed procedures.

Be sure to have all the literature on hand for all components installed: thermostat, actuators and relays.

Look at the wiring diagrams, and study them carefully. Be sure that you understand how the system is supposed towork.

Make the wiring according to the wiring diagrams. Respect polarity for 24 Vac power terminals between multiplethermostats if the same transformer is used.

VERIFICATION OF WIRING

Test the following directly on the thermostat screw terminals or auxiliary screw terminals.

POWER SUPPLY:Confirm that you have a proper power supply to the thermostat.With an electronic meter, verify that the power supply is: 19/30 Vac, 50/60 Hz

Be sure to have at least 2 VA available for the thermostat at the transformer. Remember that this current draw is for thethermostat only, the transformer should be sized accordingly to the current draw of all the components of the system:thermostat, actuator, relays, etc...

T6984 FLOATING ACTUATOR :The thermostat uses 2 triacs ( electronic contacts ) to open and close the floating actuator.

To confirm that the actuator is working properly and operating in the right direction do the following:Install a jumper across the Common and Open screw terminals, the actuator should open.Install a jumper across the Common and Close screw terminals, the actuator should close.

The open/close output 1 uses electronic triacs. A triac is the equivalent of an electronic dry contact.

These triac outputs are protected with self resetting fuses and are rated at 1.1A maximum inrush, 0.5A maximumrunning. Do not go above the triacs rating.

When they are energized by the thermostat, their switching action is as follow:

24 Vac transformer0 Vac Common

24 Vac

Motor close

Motor open T6984

L

N

A

ActuatorCommon

Close

Open

B

1. The leg of the transformer being switched by the triacs is the Common leg.2. On the T6984, the common of the floating actuator being used is wired to the 24 Vac leg of the thermostat3. If the rotation is reversed, the controls will not work properly. If the rotation is reversed, reverse the Open/Close

wiring or flip the Left/Right switch on the actuator if it is equipped with one.

63-8592 52

ON/OFF OUTPUT 2 ( T6984D and T7984B models only )The thermostat use a triac to energize the on/off output 2.

To confirm that the reheat is working properly do the following:Install a jumper across the Common and On/off screw terminals, the output should energize.

The On/off output 2 uses an electronic triac. A triac is the equivalent of an electronic dry contact.

These triac outputs are protected with self resetting fuses and are rated at 1.1A maximum inrush, 0.5A maximumrunning. Do not go above the triacs rating.

When they are energized by the thermostat, their switching action is as follow:

24 Vac transformer0 Vac Common

24 Vac

Reheat

L

N

A

24 Vac reheat device

B

R1. The leg of the transformer being switched by the triac is the Common leg.

STARTUP

Important notes:• Be sure to have the proper thermostat for the proper end devices.• ( Do you have the good components for your application )• Be sure that the dip switch are set properly for your application.• For these model with 2 outputs: T6984D & T7984B & C. The setpoint limitation must be overridden for system

checkout by setting the dip switch to the following: set S=1 & S4=1.

POWER UP DELAY ON T6984 : When powering up the thermostat, the actuator will not respond to a changing setpointdemand for X minutes. X being the maximum selected running time dip switch setting of the floating actuator. Themicro-processor is making sure that the actuator is fully closed before taking control. So for X minutes after poweringup the thermostat the actuator will not respond to a setpoint change.

53 63-8592

OUTPUT 1 & OUTPUT 2 TESTING

1. CHANGEOVER: If the thermostat is equipped with automatic changeover, disconnect any wires at the changeover input.2. NSB: If the thermostat is equipped NSB, disconnect any wires at the NSB input.3. For model with 2 outputs: ( T6984D & T7984B & C ) The setpoint limitation must be overridden for system

checkout by setting the dip switch to the following: set S=1 & S4=1.4. The room temperature needs to be between 60 to 80°F

The following procedures can be used to test output 1 of the thermostat.Also monitor the internal service LED to confirm the operations.

T6984 Actuator ( output 1 ) in cooling modeRotate setpoint dial to: Output 1 actuator Output 1 internal LED Output 2:

if usedOutput 2 internal LED

Minimum position Opening Green on (opening) Not energized Red ( Off )

Maximum position Closing Yellow on (closing) Energized Red ( On )

T6984 Actuator ( output 1 ) in heating modeInstall a jumper across the Common and changeover screw terminals

Rotate setpoint dial to: Output 1 actuator Output 1 internal LED Output 2:if used

Output 2 internal LED

Minimum position Closing Yellow on (closing) Not energized Red ( Off )

Maximum position Opening Green on (opening) Energized Red ( On )

T7984 Actuator ( output 1 ) in cooling modeRotate setpoint dial to: Output 1 actuator Output 1 internal LED Output 2:

if usedOutput 2 internal LED

Minimum position Opening Green on (opening) Not energized Red ( Off )

Maximum position Closing Green off (closing) Energized Red ( On )

T7984 Actuator ( output 1 ) in heating modeInstall a jumper across the Common and changeover screw terminals

Rotate setpoint dial to: Output 1 actuator Output 1 internal LED Output 2:if used

Output 2 internal LED

Minimum position Closing Green off (closing) Not energized Red ( Off )

Maximum position Opening Green on (opening) Energized Red ( On )

When done, connect back all wires and reset setpoint dial definition dip switch to their intended value.

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55 63-8592

Home and Building Control Home and Building Control Honeywell Asia Pacific Inc.Honeywell Inc. Honeywell Limited-Honeywell Limitee Room 3213-3225Honeywell Plaza 155 Gordon Baker Road Sun Hung Kai CentreP.O. Box 524 North York, Ontario No. 30 Harbour RoadMinneapolis, MN 55408-0524 M2H 3N7 Wanchai

Hong KongHoneywell Latin American Region Honeywell Europe S.A.480 Sawgrass Corporate Parkway 3 Avenue du BourgetSuite 200 1140 BrusselsSunrise, FL 33325 Belgium

63-8592 M.L. 2-98

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Documents

63-8592 - Application Manual for T6984 & T7984 Series