Honeywell T775abm Manual

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
1162-0254—13
CHECKOUT
Inspect all wiring connections at the controller terminals, 
and verify compliance with the installation wiring 
diagrams.
WARNINGElectrical Shock Hazard.
Can cause severe injury, death or property 
damage.
Disconnect power supply before beginning wiring 
or making wiring connections, to prevent electrical 
shock or equipment damage.
If any wiring changes are required, first be sure to remove 
power from the controller before starting work. Pay 
particular attention to verifying the power connection (24, 
120, or 240 Vac).
After the controller is installed and wired, apply power.
Power Loss
The date and time settings are retained for 24 hours after 
a power outage. After a power loss of more than 24 hours, 
the date and time settings may need to be reentered. All 
other settings are stored permanently.
Temperature Sensor Calibration
As wire length increases, resistance increases and thus 
the temperature reading increases. If necessary, calibrate 
the sensor input by reducing the value by the amount 
shown in the Table 3. For example, a wire run with 18 
gauge wire of 1,000 feet, requires a calibration offset of 
-6.0° F (-21° C).
IMPORTANT
If the calibration value in the table exceeds the 
controller’s calibration limits of +/-10° F (+/-6° C), 
you must use a heavier gauge wire.
For example, with a wire run of 1,000 feet you 
must use 20 AWG wire or heavier in order to 
calibrate for wire loss within the limits of the 
controller.
See “2.2.2.2. CALIBRATE (the sensor)” on page 18 for 
the instructions to enter the calibration value.Fig. 23 shows how sensor resistance varies with 
temperature for a sensor having a positive temperature 
coefficient (PTC) of 2.1 Ohms per degree F (3.85 Ohms 
per degree C)
.
Fig. 23. Sensor Resistance vs. Temperature. Table 3. Temperature Sensor Calibration for Resis-
tance Loss Due to Wire Length.
AW G
Rating mΩ/ftTemperature Offset in 
°F (Foot)
a
a
This is the distance from the controller to the sensor 
(already accounts for round trip distance).200 ft 500 ft 1,000 ft
14 2.5 0.46 1.14 2.28
16 4.0 0.72 1.82 3.64
18 6.4 1.16 2.90 5.82
20 10.2 1.86 4.64 9.28
22 16.1 2.92 7.32 14.64
AW G
Rating mΩ/mTemperature Offset in 
°C (Meter)
a
100 m 200 m 300 m
14 8.3 0.44 0.86 1.30
16 13.2 0.68 1.38 2.06
18 21.0 1.10 2.18 3.28
20 33.5 1.74 3.48 5.22
22 52.8 2.74 5.48 8.22
M24304
TEMPERATURE (DEGREES)
RESISTANCE (OHMS)
1403
1317
1231
11 4 5
1059
973
20 40 60 80 100 120 140 160 180 200 220
0 10 20 30 40 50 60 70 80 90 100°F
°C 0 -20 -40
120
11 0250-40 -20 -10-30
1489
887
801
1097 ± 0.08 OHMS
AT 77°F (25°C)
POSITIVE TEMPERATURE COEFFICIENT (PTC) OF 2.1 OHMS PER °F1
1 
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
62-0254—1312
INTERFACE OVERVIEW
The T775A/B/M controllers use an LCD panel and 
6-button keypad to provide status information and permit 
user input of the programming, setup, and scheduling 
parameters.
The following figure describes the display areas of the 
LCD and the keypad
.
Fig. 24. LCD Display - Home Screen And Keypad.
Menu Area – On the home screen, the LCD displays the 
configured relays and whether they are active. In 
Program, Setup or Schedule mode, the LCD displays the 
current menu selection and its order within the menu 
hierarchy.
Data Area – On the home screen, the LCD displays the 
sensors and outputs status. In Setup or Program mode, 
the LCD displays menu choices, parameter selections, 
and data values.
Lock Icon – The icon indicates the MENU button is 
locked and prevents access to the Setup and Program 
menus.
NOTE: Pressing and holding the HOME and MENU 
buttons simultaneously for five seconds 
locks/unlocks the MENU button.
6-Button Keypad – The keypad is used to access the 
menus and enter values (See “Using the LCD Panel 
Interface”).
Using the LCD Panel Interface
The 6-button keypad is used to move through the menus 
and enter or change parameter values.
Home Button
Pressing the HOME button at any time exits the current 
Programming or Setup display screen and returns to the 
home screen as shown in Fig. 24 and Fig. 25.
Menu Button
•Pressing the MENU button always displays the 
Program menu. If you are in Setup mode, you exit 
setup and return to the Program menu.
• Pressing and holding the MENU button for five 
seconds leaves the current screen and displays 
the Setup menu.
Left and Right Arrow Buttons ( and )
Use these buttons to move backward () and forward 
() through the Program and Setup menus.
Up and Down Arrow Buttons ( and )
Use these buttons to move your selection up and down 
through a menu or list.
• When the desired item is highlighted, you press the 
 arrow button to display that item’s content.
• When a value is displayed (e.g. 70° F), the up and 
down arrows increase and decrease the value.
NOTE: Once you select an item from a list or enter a 
value, pressing the
  or  or HOME but-
ton accepts your selection or value and 
stores it in the controller’s memory.
Home Screen
In the normal run state, the LCD home screen displays 
the current sensed temperatures, the modulating outputs 
status, the active status of the output relays, and error and 
status codes. 
Active relays are indicated by the small black square („) 
just below the relay number. Fig. 25 shows the home 
screen with relays 1, 2, and 4 energized. 
Pressing the 
 and  buttons from the home screen 
cycles through each modulating output that is paired with 
the sensor it controls and the active output relays
.
Fig. 25. LCD Display - Home Screen Displaying 
Sensors, Active Relays, and Mod Outputs.
NOTE: The modulating output home screen and the 
relay home screen do not dynamically update 
the active relay status, sensor values, and 
modulating output percentages. The 
information is a snapshot taken when you 
press the 
 or  button to display the 
screen.
MOD1             40%
MOD2             60%
DI ON
HOME
RELAYS  1  2  3  4
        ON
SENSORSSENSOR A78SENSOR B84
MENU AREA
home menuF o
F o
DATA AREA
LOCK ICON
6 BUTTON KEYPAD
M24488
MOD1             40%
MOD2             60%
DI ON            HOME
RELAYS  1  2  3  4
        ON
SENSORS
SENSOR A
78SENSOR B84
o
oF
F
MOD1             40%
MOD2             60%
DI ON            HOME
RELAYS  1  2  3  4
        ON
oF
oF REL 1          ON
HEAT
SETPOINT
60SENSOR A62
RT 12345 HRS
DI ON            HOME
RELAYS  1  2  3  4
        ON
MOD 1          40%
COOL
SETPOINT
74SENSOR A62
o
oF
F
M24489
MOD1             40%
MOD2             60% 
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
1362-0254—13
IMPORTANT
After four minutes of inactivity (no buttons 
pressed), the LCD display reverts to the home 
screen display.
Accessing the Menus
Menus are used for programming, scheduling, viewing the 
summary settings, and setup of advanced options.
Programming, Scheduling, and 
Summary Menus
To access these menus from the home screen, press the 
MENU button (See Fig. 26)
.
Fig. 26. Menus.
Depending on whether scheduling is enabled or not, the 
LCD displays one of two menus as shown in Fig. 26. 
Scheduling is enabled from the Setup menu’s Output 
settings (See “2.3.3.1. USE SCHED” on page 25).
Setup Menu
To access the Setup menu, press and hold the MENU 
button for five seconds (Refer to Fig. 27).
Fig. 27. Setup Menu.
Using the Menus
When you are working with the menus, use the:
• Left arrow button (
) to scroll backward through 
the menus •Right arrow button () to select the 
highlighted menu item and display its content
• Up and Down arrow buttons (
 and ) to scroll up 
and down through a list of items or to increase or 
decrease the value of a displayed parameter
NOTE: If you press the HOME button or there is no 
keypad activity for four minutes, you exit 
Program mode and return to the home 
screen.
If you press the MENU button, you exit and 
return to the menu.
MENU
PROGRAM
EXIT
homemenuORMENU DISPLAY WHEN
SCHEDULING IS NOT SET MENU DISPLAY WHEN
SCHEDULING IS SET
MENU
MOD1             40%
MOD2             60%
DI ON            HOME
RELAYS  1  2  3  4
        ON
F o 
F o  SENSORS
SENSOR A
      78SENSOR B      84
PROGRAM
SCHEDULE
SUMMARY
EXIT
M24490
homemenu
SETUP
MOD1             40%
MOD2             60%
DI ON            HOME
RELAYS  1  2  3  4
        ON
FIVE
SECONDS F o 
F o  SENSORS
SENSOR A
      78SENSOR B      84
SENSORS
OUTPUTS
EXIT
M24491 
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
62-0254—1314
1. PROGRAMMING
The controller must be programmed before being placed 
into service.
IMPORTANT
During programming, the controller is live at all 
times. For example, the contacts may open and 
close when adjusting the setpoint.
The Programming process uses a hierarchical menu 
structure that is easy to use. You press the 
 and  
arrow buttons to move forward and backward through the 
menus. 
NOTES:
1. The controller interface is intuitive. You may 
find that you do not need the following 
procedure instructions to program the 
controller. You may want to use this 
procedure simply as a reference to locate the 
particular option or parameter of interest.
2. The menus can display only those relays that 
are defined in Setup (See “2.3.2. NBR OF 
RELAYS” on page 24). For example, if you 
configure only two relays, then only two relays 
display on the appropriate menus.
3. If you press the HOME button or there is no 
keypad activity for four minutes, you exit 
Program mode and return to the home 
screen.
4. If you press the MENU button, you exit 
Program mode and return to the menu.
Setpoint and Differential
The following describes the relationship between setpoint 
and differential for heating and cooling. These settings are 
programmed for each output relay.
Heating Mode Setpoint and Differential
In heating mode, the differential is below the setpoint. The 
relay de-energizes when the temperature rises to the 
setpoint. As the temperature drops to the setpoint minus 
the differential, the relay energizes.
Cooling Mode Setpoint and Differential
In cooling mode, the differential is above the setpoint. The 
relay de-energizes when the temperature falls to the 
setpoint. As the temperature rises to the setpoint plus the 
differential, the relay energizes.
Setpoint High Limit
You can set a single irreversible setpoint high limit 
maximum value, which is applied to all outputs.
Adjust the setpoint (at any output) to the desired 
maximum setpoint. Then, simultaneously press the 
home, 
, and  buttons and continue to press all three 
buttons for five seconds to set the setpoint high limit 
maximum to this value.
NOTE: You must press all three buttons at exactly 
the same time for this action to occur.
IMPORTANT
1. This action sets the maximum setpoint value of 
all outputs to the setpoint high limit maximum.
2. Setting the high limit setpoint maximum is 
irreversible. If you perform the action 
inadvertently gently and this setpoint adversely 
affects the control of your system, you must 
replace the controller.
Programming the T775A/B/M 
Controller
To program the controller, perform the following 
procedures in the order listed:
1.Enter Program mode — see “1.1. Entering Program 
Mode” 
2.Program the Outputs — see “1.2. Program Menu for 
Outputs”
When programming is complete, you may continue with 
“3. SCHEDULING” on page 30 or, for advanced options, 
continue with “2. SETUP (ADVANCED OPTIONS)” on 
page 17.
Fig. 28. Program Menu.
1.1. Entering Program Mode
Press the MENU button, then select PROGRAM and 
press the  button to view the Program menu.
Fig. 28 shows the Program menus for controllers with and 
without Modulating Outputs.
NOTE: Modulating outputs are not available on the 
T775A and T775B controller models.ORMENU
 PROGRAM
MENU
PROGRAM
M24492
RELAY 1
RELAY 2
RELAY 3
RELAY 4
EXIT
MENU
PROGRAM
MOD 1
MOD 2
RELAY 1
RELAY 2
RELAY 3
RELAY 4
EXIT 
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
1562-0254—13
Fig. 29. Program Menu Outputs.
1.2. Program Menu for Outputs
Press the MENU button, select PROGRAM, then select 
RELAY 1 (or MOD 1) to view the parameters. Fig. 29 
shows RELAY 1.
NOTE: For MOD 1 and 2, THROT RNG replaces 
DIFFRNTL.
NOTE: The Setback parameter displays only if 
scheduling is enabled (See Fig. 57 on 
page 24) or the DI Option is set to Setback. 
(See Fig. 60 on page 26).
Continue with “1.2.1. SETPOINT”.
Fig. 30. Program - Setpoint.
1.2.1. SETPOINT
1.From the menu, use the  and  buttons to 
highlight SETPOINT.
2.Press the 
 button to display the setpoint value.
3.Use the  and  buttons to increase/decrease 
the desired setpoint temperature.
Default: 70° F (21° C)
Range: -40° to 248° F (-40° to 120° C)
4.Press the 
 button to accept the setpoint 
temperature and display the next option.
Fig. 31. Program - Differential or Throttling Range.
1.2.2. DIFFERENTIAL or THROTTLING 
RANGE
Differential is used for Relay outputs and Throttling Range 
is used for Modulating outputs.
1.From the menu, use the
  and  buttons to 
highlight THROT RNG or DIFFERNTL.
2.Press the 
 button to display the throttling range 
value.
3.Use the
  and  buttons to increase/decrease 
the desired value. 
Default: 20° F (-7° C)
Range: 1° to 300° F (1° to 149° C).
4.Press the 
 button to accept the value and display 
the next option.
In heating mode, the Differential is below the setpoint. The 
relay de-energizes when the temperature rises to the 
setpoint. As the temperature drops to the setpoint minus 
the Differential, the relay energizes.
In cooling mode, the Differential is above the setpoint. The 
relay de-energizes when the temperature falls to the 
setpoint. As the temperature rises to the setpoint plus the 
Differential, the relay energizes.
The Throttling Range brackets the setpoint setting, e.g., if 
the setpoint is 72°F (22° C) and the throttling range is 
10° F (-12° C), then the effective throttling temperature 
range is 67° to 77° F (19° to 25° C). This applies to both 
modulating outputs and floating outputs.
PROGRAM
           RELAY 1MENU
PROGRAM
RELAY 1
SETPOINT
DIFFRNTL
SENSOR
HEAT/COOL
SETBACK
EXIT
M24493
ENTER
SETPOINT
FOR 
RELAY 1
PROGRAM
RELAY 1
SETPOINTMENU
PROGRAM
RELAY 1
SETPOINT
70F o 
M24494
ENTER
DIFFERENTIAL
FOR 
RELAY 1
PROGRAM
RELAY 1
DIFFRNTLMENU
PROGRAM
RELAY 1
DIFFRNTL
20F o 
M24495 
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
62-0254—1316
Fig. 32. Program - Sensor.
1.2.3. SENSOR
1.From the menu, use the  and  buttons to 
highlight SENSOR.
2.Press the 
 button to display the sensor selec-
tions.
3.Use the
  and  buttons to select Sensor A or 
B.
4.Press the 
 button to accept the highlighted sen-
sor and display the next option.
Fig. 33. Program - Heat/Cool.
1.2.4. HEAT/COOL
1.From the menu, use the  and  buttons to 
highlight HEAT/COOL.
Default: HEAT
2.Press the 
 button to display the heat and cool 
selections.
3.Use the
  and  buttons to select Heat or Cool.
4.Press the  button to accept the highlighted 
selection and display the next option.
Fig. 34. Program - Setback.
1.2.5. SETBACK
The Setback temperature option displays if scheduling is 
enabled (See Fig. 57 on page 24) or the DI Option is set 
to Setback. (See Fig. 60 on page 26).
This is the desired setpoint temperature that you want to 
use during setback mode for this output. For example, if 
your setpoint is 70° F (21° C) and you want the 
temperature to drop 10° F during setback mode, enter 
60° F (16° C) as the setpoint for this output.
1.From the menu, use the
  and  buttons to 
highlight SETBACK.
2.Use the
  and  buttons to increase/decrease 
the desired setpoint temperature.
Default: 60° F (16° C)
Range: -40° to 248° F (-40° to 120° C)
3.Press the 
 button to accept the value and display 
the menu.
1.2.6. Program Next Output (Mod or Relay)
For the next output (Mod or Relay), select the desired 
output from the Program menu (Refer to Fig. 28 on 
page 14).
Go to “1.2.1. SETPOINT” on page 15 to program the next 
output.
When you finish programming the outputs, continue with 
“1.2.7. Exiting Program Mode” on page 17.
MENU
PROGRAM
RELAY 1
SENSOR
SELECT
SENSOR FOR
RELAY 1
SENSOR A
SENSOR B
PROGRAM
 RELAY 1
 SENSOR
M24496
PROGRAM
 RELAY 1
 HEAT/COOLMENU
PROGRAM
RELAY 1
HEAT/COOL
SELECT
HEAT/COOL
FOR 
RELAY 1
HEAT
COOL
M24497
ENTER
SETBACK
SETPOINT 
FOR RELAY 1
PROGRAM
 RELAY 1
 SETBACKMENU
PROGRAM
RELAY 1
SETBACK
60F o 
M24498 
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
1762-0254—13
Fig. 35. Program - Exit.
1.2.7. Exiting Program Mode
Press the HOME button to leave programming mode and 
return to the home screen.
This completes the programming procedure.
2.SETUP (ADVANCED OPTIONS)
Setup provides the ability to change the factory default 
settings for the temperature sensors and outputs, to 
enable/disable reset control, and to enable/disable 
scheduling.
NOTE: The controller interface is intuitive. You may 
find that you do not need the following setup 
instructions for the sensors and outputs. You 
may want to use this procedure simply as a 
reference to locate the particular option or 
parameter of interest.
NOTES:
1. If you press the HOME button or there is no 
keypad activity for four minutes, you exit 
Setup mode and return to the home screen.
2. If you press the MENU button, you exit Setup 
mode and return to the menu.
Setup Procedure
The Setup process uses a hierarchical menu structure 
that is easy to use. You press the  and  arrow buttons 
to move forward and backward through the menus.
NOTE: The menus can display only those relays that 
are defined in Setup (see “2.3.2. NBR OF 
RELAYS” on page 24). For example, if you 
configure only two relays, then only two 
relays display on the appropriate menus.Once in Setup mode, you use the — 
• Left arrow button (
) to scroll backward through the 
Setup menus
• Right arrow button (
) to select the highlighted menu 
item and display its content
• Up and Down arrow buttons (
 and ) to scroll up 
and down through a list of items or to increase or 
decrease the value of a displayed setup parameter
To change the controller’s sensors and output setup 
parameters, perform the following procedures in the order 
listed:
1.Enter Setup mode — see “2.1. Entering Setup 
Mode”
2.Setup Sensors — see “2.2. Setting up the Sensors”
3.Setup Outputs — see “2.3. Setting up the Outputs” 
on page 21
4.Exit Setup Mode — see “2.4. EXIT Setup Mode” on 
page 30
2.1. Entering Setup Mode
To enter Setup mode, press and hold the MENU button for 
five seconds to display the Setup menu. Refer to Fig. 27 
on page 13.
Fig. 36. Setup - Sensors Menu.
2.2. Setting up the Sensors
1.From the Setup menu, use the  and  buttons 
to highlight SENSORS.
2.Press the 
 button to display the Sensors menu.
MENU
PROGRAM
MOD 1
MOD 2
RELAY 1
RELAY 2
RELAY 3
RELAY 4
EXIT
M24499
 SETUP
 SENSORSSETUP
SENSORS
# SENSORS
SENSOR A
SENSOR B
EXIT
M24500 
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
62-0254—1318
Fig. 37. Setup - Sensors - Number of Sensors.
2.2.1. Number of SENSORS
The value entered here determines the number of 
sensors displayed on the home screen.
1.From the Sensors menu, highlight # SENSORS 
then press the 
 button to display the number of 
sensors.
2.Use the
  and  buttons to enter the number of 
sensors (1 or 2).
Default: 2
3.Press the 
 button to accept the value and display 
the SENSOR A selection.
Fig. 38. Setup - Sensors - Sensor A Menu.
2.2.2. SENSOR A
1.From the Sensors menu, highlight SENSOR A.
2.Press the  button to display the Sensor A 
selections.
Fig. 39. Setup - Sensors - Sensor A - Units.
2.2.2.1. UNITS (° F or ° C)
IMPORTANT
This is a global change and affects the unit 
values for all temperature parameters on all 
displays.
The UNITS screen displays only for Sensor A.
1.From the Sensor A selections, use the
  and  buttons to highlight UNITS.
2.Press the  button to display the temperature 
units.
3.Use the
  and  buttons to highlight F or C.
Default: F (Fahrenheit)
4.Press the 
 button to accept the units and return 
to the Sensor A selections.
Fig. 40. Setup - Sensors - Sensor A - Calibrate.
2.2.2.2. CALIBRATE (the sensor)
Ensure that the wire size calibration value is within the 
limits. See “Temperature Sensor Calibration” on page 11.
1.From the Sensor A selections, use the
  and  buttons to highlight CALIBRATE.
2.Press the  button to display the calibration 
degree value.
3.Use the
  and  buttons to increase/decrease 
the desired calibration degrees.
Default: 0.0
Range: +/-10° F (+/-6° C)
4.Press the 
 button to accept the value and return 
to the Sensor A selections.
ENTER
NUMBER OF 
SENSORS
SETUP
 SENSORS
 # SENSORSSETUP
SENSORS
# SENSORS
2
M24501
SETUP
SENSORS
SENSOR ASETUP
SENSORS
SENSOR A
UNITS
CALIBRATE
LABEL
EXIT
M24502
SETUP
SENSORS
 SENSOR A
   UNITSSETUP
SENSORS
SENSOR A
UNITS
SELECT
UNITS FOR
SENSOR A
DEG F
DEG C
M24503
SETUP
SENSORS
 SENSOR A
   CALIBRATE
ENTER
VALUE TO
CALIBRATE
SENSOR A
SETUP
SENSORS
SENSOR A
CALIBRATE
M24504
0.0F o  
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
1962-0254—13
Fig. 41. Setup - Sensors - Sensor A - Label.
2.2.2.3. LABEL (the sensor input)
For a sensor already labeled, the display positions to and 
highlights that label.
1.From the Sensor A selections, use the
  and  buttons to highlight LABEL.
2.Press the  button to display the label list.
3.Use the  and  buttons to scroll through list 
and highlight the desired label.
You may need to scroll up or down to view all 
possible labels.
4.Use the 
 button to accept the highlighted label 
and exit the list.
NOTE: The label names in list order are: Sensor, 
Boiler, Outdoor, Duct, Dischrg, Chiller, Room, 
Supply, Return, and Animals.
Fig. 42. Setup - Sensors - Sensor A - Exit.
2.2.2.4. Exit Sensor A Setup
Press thebutton to exit Sensor A selections and return 
to the Sensors menu.
or
Use the
  and  buttons to highlight EXIT and press 
the  button.
Fig. 43. Setup - Sensors - Sensor B Menu.
2.2.3. SENSOR B
For the T775M2030 and T775M2048 models only, which 
have a High/Low modulating temperature limit, the LIMIT 
item displays on the Sensor B menu.
1.From the Sensors menu, use the
  button to 
highlight SENSOR B.
2.Press the  
 button to display the Sensor B menu.
2.2.3.1. CALIBRATE
Setting the calibration value is accomplished the same 
way as the Sensor A. See “2.2.2.2. CALIBRATE (the 
sensor)” on page 18.
2.2.3.2. LABEL
Setting the label is accomplished the same way as the 
Sensor A. See “2.2.2.3. LABEL (the sensor input)” on 
page 19.
SETUP
SENSORS
 SENSOR  A
   LABELSETUP
SENSORS
SENSOR  A
LABEL
SELECT
LABEL FOR
SENSOR  A SENSOR  A
BOILER A
OUTDOOR A
DUCT A
DISCHRG A
CHILLER A
ROOM A
M24505
SETUP
SENSORS
SENSOR A
UNITS
CALIBRATE
LABEL
EXIT
M24506
SETUP
SENSORSSETUP
SENSORS
# SENSORS
SENSOR A
SENSOR B
EXITSETUP
SENSORS
SENSOR B
CALIBRATE
LABEL
LIMIT
EXIT
M24507 
						

							T775A/B/M SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLERS
62-0254—1320
Fig. 44. Setup - Sensors - Sensor B - Limit.
2.2.4. LIMIT (Sensor B only)
For the T775M2030 and T775M2048 models only, the 
LIMIT item displays on the Sensor B menu.
NOTE: The LIMIT option acts only on Modulating 
Output 1.
1.From the Sensors menu, use the
  button to 
highlight SENSOR B.
2.Press the  
 button to display the Sensor B menu.
3.Use the  and  buttons to select the LIMIT 
item.
4.Use the 
 button to display the Limit selections.
5.Use the  and  buttons to select the desired 
limit, (Disable, Hi Limit, or Low Limit).
Default: Disable
6.Press the 
 button to accept the value and return 
to the Sensor B menu.
When you select Hi Limit or Low Limit, the Sensor B menu 
changes and adds the Hi/Low Limit and Throttling Range 
items. 
If you are setting a Hi or Low Limit, continue with “2.2.4.1. 
HI LIMIT or LOW LIMIT (Sensor B only)”. 
If you selected Disable for the Limit value, continue with 
“2.3. Setting up the Outputs” on page 21.
Fig. 45. Setup - Sensors - Sensor B - Hi/Low Limit 
(showing Hi Limit).
2.2.4.1. HI LIMIT or LOW LIMIT (Sensor B 
only)
Fig. 45 shows the High Limit, but the process is the same 
for setting the Low Limit. 
Sensor B can be assigned a high/low limit, so that as you 
are controlling temperature at Sensor A, the control 
adjusts its modulating output to prevent exceeding the 
user-entered limit for Sensor B. 
1.From the Sensor B menu, use the
  button to 
highlight HI LIMIT or LOW LIMIT.
2.Press the  
 button display the LIMIT value.
3.Use the  and  buttons to increase/decrease 
the desired Limit value.
4.Press the 
 button to accept the value and return 
to the Limit menu.
The high and low limit action will work in either the heat or 
the cool mode as follows:
• When the low limit is used in the heat mode, the MOD1 
output increases to prevent reaching the low limit at 
sensor B.
• When the high limit is used in the heat mode, the 
MOD1 output decreases to prevent reaching the hi 
limit at sensor B.
• When the low limit is used in the cool mode, the MOD1 
output decreases to prevent reaching the low limit at 
sensor B.
• When the high limit is used in the cool mode, the 
MOD1 output increases to prevent reaching hi limit at 
sensor B.
SETUP
SENSORS
  SENSOR  B
   LIMITSETUP
SENSORS
SENSOR  B
LIMIT
SELECT
HI/LOW
LIMIT FOR
SENSOR B
DISABLE
HI LIMIT
LOW LIMIT
M24508
SETUP
SENSORS
SENSOR B
UNITS
CALIBRATE
LABEL
LIMIT
HI LIMIT
THROT RNG
EXIT
SETUP
SENSORS
 SENSOR  B
ENTER
VALUE FOR
SENSOR B
HI LIMITSETUP
SENSORS
SENSOR B
HI LIM
90F o 
M24509