Honeywell T775U Series 2000 Installation Instructions Manual page 11

Table 4. Temperature Sensor Calibration for
Resistance Loss due to Wire Length.
Temperature Offset in
AWG
Rating m /ft 200 ft
14 2.5 0.46
16 4.0 0.72
18 6.4 1.16
20 10.2 1.86
22 16.1 2.92
Temperature Offset in
AWG
Rating m /m 100 m
14 8.3 0.44
16 13.2 0.68
18 21.0 1.10
20 33.5 1.74
22 52.8 2.74
a
This is the distance from the controller to the sensor
(already accounts for round trip distance).
Fig. 19 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).
RESISTANCE (OHMS)
1489
1403
1317
1231
1145
1059 1097 ± 0.08 OHMS
AT 77°F (25°C)
973
1
887
801
-40 -20 0 20 40 60 80 100 120 140 160 180 200 220
-40 -30 -20 -10 0 10 20 30 40 50
TEMPERATURE (DEGREES)
POSITIVE TEMPERATURE COEFFICIENT (PTC) OF 2.1 OHMS PER °F
1
Fig. 19. Sensor Resistance vs. Temperature.
INTERFACE OVERVIEW
The T775U controller uses 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.
T775U SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLER
a
°F (Feet)
500 ft 1,000 ft
1.14 2.28
1.82 3.64
2.90 5.82
4.64 9.28
7.32 14.64
a
°C (Meter)
200 m 300 m
0.86 1.30
1.38 2.06
2.18 3.28
Fig. 20. LCD Display - Home Screen And Keypad.
3.48 5.22
Menu Area – On the home screen, the LCD displays the
5.48 8.22
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 but-
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.
250 °F
Home Button
60 70 80 90 100 110 120 °C
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. 20 and Fig. 21.
M24304
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 (
Use these buttons to move backward ( ) and forward ( )
through the Program and Setup menus.
11
HOME
RELAYS 1 2
MENU AREA
ON
SENSORS
SENSOR A
78
o
F
SENSOR B
84
o
F
DATA AREA
MOD1 40%
MOD2 60%
LOCK ICON
DI ON
home menu
6 BUTTON KEYPAD
tons simultaneously for five seconds locks/
unlocks the MENU button.
M24563
)
and
62-0255—07