General DT80-1 User manual

DIGITAL THERMOCOUPLE
THERMOMETERS
USER’S MANUAL
DT80-1 and DT80-2
Please read this man al caref lly and thoro ghly before sing this prod ct.
Single
Therm c uple
Dual
Therm c uple

2
TABLE OF CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Operating Instructions . . . . . . . . . . . . . . . . . . . . . . . . 5
Display Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Function Keys Overview . . . . . . . . . . . . . . . . . . . . . . . 7
pecific Operating Instructions . . . . . . . . . . . . . . 8 –9
pecifications . . . . . . . . . . . . . . . . . . . . . . . . . . 10 – 11
Maintenance & Troubleshooting . . . . . . . . . . . . . . . . 11
Replacing the Battery . . . . . . . . . . . . . . . . . . . . . . . . 11
Routine Maintenance . . . . . . . . . . . . . . . . . . . . . . . . 11
Replacement Parts . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Warranty Information . . . . . . . . . . . . . . . . . . . . . . . . 12
Return Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

INTRODUCTION
Thank you for purchasing a Thermocouple type J/K
digital thermometer from General Tools & Instruments.
We suggest that you read this user’s manual carefully
and thoroughly before using the instrument.
The DT80-1 and DT80-2 are thermocouple-type J/K
digital thermometers. The DT80-1 is designed to be used
with a single thermocouple; the DT80-2 is designed to be
fed by two thermocouples configured to deliver a
temperature differential.
Each model uses a high-resolution analog-to-digital
converter chip and a microprocessor to convert input
temperature signals to digital form and display them on
a dual-display, 5-digit black-and-white liquid crystal
display measuring 1.5 by 1.5 inches.
These two thermocouple thermometers have a
measurement accuracy of ±(0.05% of reading + 1.4°F)
with an unmatched measurement range. For example,
the DT80-1 and DT80-2 can measure and read out
temperatures from -328° to 1922°F (-200° to 1050°C)
using a J-type thermocouple, and temperatures from
-328° to 2498°F (-200° to 1370°C) using a K-type
thermocouple. This very wide measuring range, plus a fast
response time make these thermocouple thermometers
suitable for a wide range of commercial and industrial
applications requiring measurement of very high and low
temperatures. Examples include applications in the food
and chemical processing industries, VAC (heating,
ventilation and air-conditioning), power generation, and
paper production.
3

Simplicity is another asset of thermocouple
thermometers. Thermocouples work by measuring the
potential difference produced at the junction of two wires
made of different metals but exposed to the same
temperature. Since the junction is very small, a
thermocouple thermometer can be used to measure the
temperature at a point reachable by a probe. The probes
used are inexpensive and easily replaceable.
KEY FEATURES
• Dual 5-digit liquid-crystal display
• Measurement range: -328° to 1922°F
(-200° to 1050°C) using a J-type thermocouple;
-328° to 2498°F (-200° to 1370°C)
using a K-type thermocouple
• Measurement accuracy:
±(0.05% of reading +1.4°F)
• Operating temperature range:
40° to 104°F (5° to 40°C)
• Power Source: 1 “9V” battery
4

O ERATING INSTRUCTIONS
Familiarize yourself with the nomenclature in the
following two illustrations before using the DT80-1 or
DT80-2.
BACK, FRONT AND TO VIEWS
Thermocouple T1 input
Thermocouple T2 input (DT80-2 only)
 Display (see next illustration)
 Function keys
 Battery cover
 Battery compartment
5

DIS LAY ELEMENTS
Auto power off icon
 Low battery indicator
 old (freeze) display indicator
 Offset change indicator
 Enable Maximum, Minimum and Average recording;
also indicates Current Mode.
 Offset Setup Mode indicator
 Limit indicates that the alarm function is enabled;
i and Lo indicate the reason why alarm sounded.
 T1 - T2: Indicates differential temperature mode
(DT80-2 only).
 Primary display: Indicates state of channels, selected
temperature unit and thermocouple type.
 Secondary display: Indicates state of channels, se-
lected temperature unit and thermocouple type.
Note: When a thermocouple is not plugged into the
instrument, the display reads “OL”
6

FUNCTION KEYS OVERVIEW
Pressing toggles between Celsius and Fahrenheit
temperature units (scale chosen is saved upon
shutdown and becomes the default of next power
up cycle).
Pressing enables/disables holding (freezing) of
display and updating of data. Pressing and holding
enables/disables auto power off function
(indicated by ).
In normal operating mode, toggles to select J- or
K-type thermocouple. In offset setup mode,
increases the offset value.
In normal operating mode, selects display of
maximum, minimum, or average temperatures. In
offset setup mode, pressing saves setting
and exits that mode.
Pressing and holding enters offset setup mode.
In normal operating mode, pressing turns
instrument on or off. In offset setup mode,
pressing decreases offset value.
(DT80-2 only). Pressing enables/disables T1 minus
T2 function. Pressing and holding swaps T1 and
T2 readings between primary and secondary
displays.
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T1-T2
T1➝T2
➝
TYPE
O
HOLD
MAX
MIN
REL
ºC/ºF
MAX
MIN

S ECIFIC O ERATING
INSTRUCTIONS
To display maximum, minimum or average
temperature , push the key repeatedly until the
corresponding icon appears above the reading in the
primary display. The primary display shows the current
channel reading of MAX, MIN or AVG. The secondary
display shows the current channel reading of actual
temperature. When the instrument powers off, the value
chosen is saved and becomes the default value for the
next power up cycle.
To select the thermocouple type , press the
key (in normal operating mode) until the correct letter
(K or J) appears on the left side of the primary display. In
the case of the DT80-2, use the key to also set the
correct thermocouple type in the secondary display. Both
the DT80-1 and DT80-2 will save their setting(s) upon
shutdown and make them the default when they next
power up.
To hold (freeze) the display and stop updating
measurements , press the key. Press it again to
unfreeze the display. When the OLD function is enabled,
all function keys (except for the key) are disabled.
Using the REL key to subtract readings. Pressing the
key cancels out a relative reading, changes the
display to “0” and saves the previous reading
as the standard relative reading. For example, if
the primary display is reading 25°C, pressing the
key changes the display to “0” and saves 25°C as
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T1-T2
T1➝T2
➝
TYPE
HOLD
MAX
MIN
REL
REL
O

the standard relative reading. Then, if the temperature
rises to 30°C, the display will show 5°C (30° – 25°C).
If the temperature falls to 20°C, the display will show -
5°C (20° – 25°C). Pressing the key again disables
this function and restores the actual temperature reading
to the display.
The primary display shows the current channel reading of
REL. The secondary display shows the current channel
reading of actual temperature.
In the case of the DT80-2, to show the current channel
reading of REL on the secondary display, press and hold
the key to swap T1 and T2.
To display T1 minus T2 temperature (DT80-2 only),
press the key. Press the key again to disable this
function.
The primary display shows the T1-T2 temperature. The
secondary display shows the current channel reading of
actual temperature. To swap channels, press and hold
the key.
To enable/disable the 15-minute Auto Power Off
function, press and hold the key (with the
instrument in normal operating mode) until the
appears or disappears at the upper left of the screen.
To power the instrument on and off, press the key.
If pressing the key fails to shut off the unit, that means it
is in offset setup mode. Exit this mode by pressing the
key, and then push the key again.
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T1-T2
T1➝T2
➝
T1-T2
T1➝T2
➝
T1-T2
T1➝T2
➝
REL
O
O
HOLD
MAX
MIN

To compensate for thermocouple error, you must first
set the offset value. To do so (recommended each time
the thermocouple probe is changed):
1. Press and hold the key.
2. Use the and keys, respectively, to increase
or decrease the offset value. The allowable adjustment
range is ±9°F (±5°C).
3. Press the key to save the setting and exit offset
setup mode.
To adjust the offset of the secondary channel in the
DT80-2, press the key and repeat steps 2 and 3.
The instrument will automatically save the offset value
upon shutdown, and default to it upon the next startup.
S ECIFICATIONS
• Display: dual 5-digit LCD
• Temperature units: Degrees Celsius or Fahrenheit
• Display resolution: 0.1
• Measurement range: -328° to 1922°F (-200° to
1050°C) using a J-type thermocouple; -328° to 2498°F
(-200° to 1370°C) using a K-type thermocouple
• Measurement accuracy: ±(0.05% of reading + 1.4°F)
• upplied Probe(s) Range: 50º to 500ºF (-45º to 260ºC)
• Operating temperature range: 40° to 104°F
(5° to 40°C), below 80% R
• torage temperature range: 14° to 140°F
(-10° to 60°C), below 70% R
10
REL
TYPE O
MAX
MIN
T1-T2
T1➝T2
➝