UNI-T UT321, UT323, UT325, UT322 Operating Manual

Refer to safety information in Table 1 and the international symbols in Table 2.

Table 1. Safety Information

Before using the thermometer inspect the case. Do not use the thermometer if it
appears damaged. Look for cracks or missing plastic. Pay particular attention to
the insulation around the connectors.
Disconnect the thermocouple(s) from the thermometer before opening the case.
Replace the batteries as soon as the battery indicator (

) appears. The
possibility of false readings can lead to personal injury.
Do not use the thermometer if it operates abnormally. Protection may be
impaired. When in doubt, have the thermometer serviced.
Do not operate the thermometer around explosive gas, vapor, or dust.
Do not apply more than the rated voltage, as marked on the thermometer (30V),
between the thermocouple(s), or between any thermocouple and earth ground.
When potential differences are anticipated between the thermocouples, use
electrically insulated thermocouples.
When servicing the thermometer, use only specified replacement parts.
Do not use the thermometer with any part of the case or cover removed.

A warning identified conditions and actions that pose hazards to the user. To avoid
electrical shock or personal injury, follow these guidelines:

Warning

Caution

A caution identifies conditions and actions that may damage the meter or the
equipment under test.

Use the proper thermocouples, function, andthe range of your thermometer.
When carrying two thermocouples measurement, make sure there are no
potential differences between two thermocouples.
Do not attempt to recharge the battery.
Match the + and – polarities of the battery with the battery case.

Table 2. International Symbols

Refer to the manual for information about this feature

Complies with European Union directives

Battery

Get Acquainted with Your Thermometer

Unless otherwise specified, all the descriptions apply to all Models of UT321,
UT322, UT323 and UT325.

To become familiar with the thermometer, study the following:

Figure 1 and Table 3 for components;
Figure 2 and Table 4 for LCD display;
Figure 3-a and 3-b and Table 5 for button functions;

Figure 1. Components

Table 3. Components

Display

Buttons

Thermocouple T1 input

Thermocouple T2 input (UT323 and UT325 only)

USB Port

SIGN Port - Over Limit Signal Output (UT323 and UT325 only)

NTC

Battery Door

9V battery (6F22 )

1

2

3

4

5

6

7

8

9

Table 4. LCD Display

Setup is in progress when the icon blinks
Display readings of maximum, minimum and average
Data Transferring is in progress
Logged readings are displayed when the icon blinks
Low battery indicator. Replace the battery
The thermocouple type
The temperature units
Secondary Display 2
Under Calibration mode when the icon blinks. The displayed reading is fixed.
Secondary Display 1
The thermocouple measurement includes an offset. See “Changing Setup
Options”
Readings are being logged when the icon blinks
Primary Display
Data hold function is active.
The symbol of display backlight

1
2
3
4
5
6
7
8
9

10

11

12
13
14

Figure 3-a UT321 and UT323 Keypad

Figure 3-b UT322 and UT325 Keypad

Table 5. Buttons

Press to turn the thermometer on or off

Press to turn the display backlight on and off.
Press to freeze or unfreeze the displayed readings
Press to switch between Celsius (ºC), Fahrenheit(ºF), and Kelvin (K)
Press to step through the maximum, minimum, and average

readings. Press and hold to exit this function.

Press to step through K-, J-, T-, E- (R-, S-, N-) type thermocouple.

Press to select and show T1, T2 and T1-T2 (differential temperature
measurement) in the primary or secondary display 1

Press to enter USB mode and the USB icon blinks. Press again
to exit USB mode.

Press to start or stop logging.
(See “Using Memory - Starting and Stopping Logging”.)

Press to show logged readings
Press again to stop.

MAX MIN

HOLD

ºC ºF

SEND

STORE

RECALL

Press to start or exit Setup.
Press to scroll the Setup option you want to change
(See “Changing Setup Options”)
After entering the Setup mode, press to increase the displayed setting.
(See “Changing Setup Options”)
After entering the Setup mode, press to decrease the displayed setting.
(See “Changing Setup Options”)

Confirm button.
(See “Changing Setup Options”)

ENTER

SETUP

Using the Thermometer

1) Plug the thermocouple(s) into the input connector(s).

2) Press the power button to turn on the thermometer.

3) Set the type of thermocouple(s) to be the same with the one plugged into the
input connector(s).

If no thermocouple is plugged into the selected input terminal or the thermocouple
is “open” or the over-range positive deviation is too big, the display
shows “_ _ _ _ “.

Changing Setup Options

Use Setup to change the following settings:
Logging interval

Thermocouple type Offset (T1) Offset (T2) (UT322 and

UT325 only)

Sleep Mode Line Frequency Time (S-T) Low Limit Alarm

(Lo) (UT323 and UT325 only)

High Limit Alarm (Hi) (UT323 and UT325 only)

Over Limit Signal Output (SI) ON/OFF (UT323 and UT325 only) Normal

Temperature Compensation(NTC) ON/OFF

DEBUG ON/OFF (UT323 and

UT325 only)

Save setting and return to normal measurement mode.

When the thermometer is in Setup mode, the display shows and blinks SETUP.

Press SETUP to start or exit Setup.
Press SETUP to scroll through the Setup options you want to change.

The logging interval determines how often the thermocouple stores logged
readings in memory. You choose the length of the logging interval. See “Using
Memory”.

Press SETUP until the display shows INTERVAL.

The thermometer stores logged readings at the end of each logging interval.
You can select a logging interval by pressing

or . Holding down or causes

the number to change more quickly.The maximum interval is 59:59 and the
minimum interval is 00:00. When the logging interval is 00.00, you need to store
the readings manually as the auto store feature will be disabled.

1. Press SETUP until the display shows TYPE.

2. Press

or to select the thermocouple type you want including K-, J-, E- type
(UT323 and UT325 have extra R-, S- and N- ttype, UT321/UT325 can use
TYPE button to change directly)).

1. Press SETUP until the display shows OFFSET and T1

2. Press

or to change the offset value. The offset range is -6~6.

1. Press SETUP until the display shows OFFSET and T2

2. Press

or to change the offset value. The offset range is -6~6.

Figure 2. Display LCD Display

LCD Display

to change until the desired sleep time is obtained.

toggle between time format "h:m" and "m:s".

5. If you don't change this option, it means the time that the meter has run
through currently.

6. The system counts the time when the user turns on the thermometer. It will
be automatically cleared once the Thermometer is dis-energized.

6. The Min.value for low alarm is the lower limit value of measuring range of the
applied thermocouple.

7. The Max. value for low alarm is the setting high alarm limit value if high alarm
is enabled (if still higher than high alarm limit value, Max. value=High Alarm
Limit Value-1), otherwise this Max. value is the upper limit value of measuring
range of the applied thermocouple.

Min. value
Max. value

High Alarm Limit Value-1

Overview

The Uni-Trend Model UT321, UT322, UT323 and UT325 Thermometers
(‘the thermometer) are microprocessor-based, digital thermometers designed
to use external J-, K-, T-, E-, R-, S- and N- type thermocouples (temperature
probes) as temperature sensors.

UT321: single input(T1), suitable for K-, J-, T- and E- type thermocouples
UT322: dual input(T1,T2), suitable for K-, J-, T- and E- type thermocouples
UT323: single input(T1), suitable for K-, J-, T-, E-, R-, S- and N- type thermocouples.
Equipped with over limit alarm, over limit signal output and user self-debug
features.
UT325: dual input(T1,T2), suitable for K-, J-, T-, E-, R-, S- and N- type
thermocouples.
Equipped with over limit alarm, over limit signal output and user self-debug features.

Use the thermometer only as specified in this manual. Otherwise, the protection
provided by the meter may be impaired.

Safety Information

“:” stop blinking. Press again to resume logging, the “:” blinks again.

Press to start storing readings in sequence according to the pre-set

P/N:110401104391X

The table below shows the measuring range of each type of thermocouple

K type: -200.0ºC to +1372ºC (-328.0 ºF to +2501 ºF)

J type: -210.0ºC to +1200ºC (-346.0 ºF to +2192 ºF)

T type: -250.0ºC to +400.0ºC (-418.0 ºF to +752.0 ºF)

E type: -150.0ºC to +1000ºC (-238.0 ºF to +1832 ºF)

For example:

The Max. value of the high alarm of K type is +1372ºC.
The Min.value of the high alarm of K type is either Low Alarm Limit Value+1

or -200ºC.

The table below shows the measuring range of each type of thermocouple

K type: -200.0ºC to +1372ºC (-328.0ºF to +2501ºF)

J type: -210.0ºC to +1200ºC (-346.0ºF to +2192ºF)

T type: -250.0ºC to +400.0ºC (-418.0ºF to +752.0ºF)

E type: -150.0ºC to +1000ºC (-238.0ºF to +1832ºF)

Measuring Temperatures

Thermocouples are color-coded based on the North American ANSI Colour
Code:

Type Colour Type Colour

J Black R Green

K Yellow S Green

T Blue N Orange

E Purple

1. Plug a thermocouple into the input connector(s).

2. Set the same thermocouple type in the thermometer.

To change the thermocouple type, see “Changing Setup Options”.

1. Press ºC ºFK to select the correct temperature unit.

2. Hold or attach the thermocouple(s) to the measured location.
The temperature shows in the selected unit on LCD.

1. Press HOLD to freeze the readings on the display. The display shows HOLD.

2. Press HOLD again to turn off the HOLD function.

1. Under temperature measurement mode, press to turn the display

2. Press

again to turn off the display backlight. The display backlight will not

turn automatically off.

1. Press MIN MAX to step through the maximum (MAX), minimum (MIN),

or the average (AVG) readings.

2. Press and hold MIN MAX to exit MIN MAX mode.

1. Plug the thermocouple into the input connector.

2. Place the thermocouple in a known, stable temperature environment (such
as an ice bath or a dry well calibrator).

3. Allow the readings to stabilize.

4. In Setup change the offset until the display reading matches the debug
temperature. (See “Changing Setup Options.”)

Setting the low alarm and high alarm limit at the SETUP mode, the thermometer
beeps when the measured temperature is higher or lower than the pre-set limit.
(See “Changing Setup Options.”)

Setting the low and high limit signal output at the SETUP mode, the SIGN port
output the corresponding signal when the measured temperature is higher or
lower than the pre-set limit. (See “Changing Setup Options.”)

Use the offset option in Setup to adjust the thermometer’s readings to
compensate for the errors of a specific thermocouple.

After entering the Debug mode, you can self-debug. Follow the procedures
as below:

K- and J- type: -180ºC, 0ºC and 900ºC
T type: -180ºC, 0ºC and 400ºC
E type: -140ºC, 0ºC and 900ºC
R- and S- type: 0ºC and 1200ºC
N type: -180ºC, 0ºC and 1200ºC
Remark: 0ºC is only for debugging K type.

Remark:
For Temperature VS Voltage table, refer to BS EN 60584 - 1:1996. Before
carrying out the debug, please ensure your standard source has the accuracy
up to the demand. Our company will not be liable for massive deviation occuring
to the accuracy of the thermometer that has been caused by improper selection
of standard source on users' side.

Using Memory

During a logging session, the thermometer stores logged readings in its memory.

The thermometer stores 00-99, total 100 sets of temperature readings. The
stored readings are from primary display.

1. Set the logging interval. (See “Changing Setup Options.”)

2. Press STORE to start logging.

DATA shows and blinks on LCD.

3. Press STORE again to stop logging.

4. If you selected a manual logging interval, set the logging interval as 00:00. Press

ENTER each time you want to store logged readings in memory. The secondary
display 1 shows the logged reading. Each presses of ENTER will automatically
store the logged readings in the next memory location. Press

or could

change the memory location, the empty location shows “- - - - - ”.

5. If you selected an auto logging interval, set the logging interval to any time
except 00:00. After entering logging mode, the secondary display 2 shows “:”

ENTER

logging interval, the “:” blinks. Press

again to pause auto logging, the

ENTER

1. Press STORE to enter logging mode, DATA shows and blinks on LCD.

2. Press and hold down STORE for 2 seconds, the display shows CLR.

3. Press ENTER to delete all the logged readings from memory. It is not
possible to delete the logged readings one by one.

The display then shows “----“

Communicating with a PC

You can transfer the data from the thermometer’s memory to a PC using the
included Software.

Press SEND button and USB blinks on the display. It means the Thermometer
has already been communicated normally to the PC. Details refer to the
Installation Guide file in the Software.

Under the influence of radiated Radio-Frequency electromagnetic Field
the captioned models have a measurement error, it will be back to normal when
the interference is removed.

Maintenance

Replace the batteries as soon as the battery indicator appears. The possibility
of false readings can lead to personal injury.

1. Turn off the thermometer.

2. Loosen the screw and remove the battery door.

3. Replace the battery with a new 9V battery (6F22). Reinstall the battery door
and tighten the screw.

Clean the surface of the thermometer with soft cloth or sponge dampened with
water or mild detergent. Do not get water inside the thermometer, otherwise it
may cause damage to internal circuits or the instrument.

Specifications

Operating Temperature

Storage Temperature

Humidity

-10ºC to 50ºC
(14ºF to 122ºF)

-40ºC to + 60ºC
(-14ºF to +140ºF)

Non condensing <10ºC (<50ºF)
95% RH: 10ºC to 30ºC (50¨ºF to 86ºF)
75% RH: 30ºC to 40ºC (86ºF to 104ºF)
45% RH: 40ºC to 50ºC (104ºF to 122ºF)

Certification

Safety

EN61326: 2006, EN55022: 2006 and EM55024: 1998+A1+A2

Function UT321 UT322 UT323 UT325 Input
Protection

Type

Input

Measurement
Range

Display
Resolution

Measurement

Accuracy

K, J, T, E K, J,T, E, R, S, N

T1 T1, T2 T1 T1, T2

K type: -200.0ºC to +1372ºC (-328.0 ºF to +2501 ºF)

J type: -210.0ºC to +1200ºC (-346.0 ºF to +2192 ºF)

T type: -250ºC to +400.0ºC (-418 ºF to +752.0 ºF)

E type: -150.0ºC to +1000ºC (-238.0 ºF to +1832 ºF)

0.1ºC ºF/K…. (<1000) (T type below -200ºC and R
type, S type is 1ºC ºF/K)

1.0ºC ºF/K…. (>1000)

K-,J-,T-, E- type:
±(0.2%+0..6ºC(1.2ºF))

R,S type: ±(0.2%+2ºC(4ºF))
N type: ±(0.2%+1.5ºC(3ºF))

±(0.5%+0.8ºC(1.6ºF))

30V

Below -10ºC: add 0.5ºC
Below -200ºC, add +2ºC
Type T Below -200ºC: for reference only.

50 times per second, Updates 2-3 times per second

Relative Time

0 ~ 99 sets

Logging Interval, Thermocouple Type, Offset (T1),
Offset (T2) (UT322 and UT325 only), Sleep Mode,
Line Frequency, Time, High/Low Limit (UT323 and
UT325 only), Over Limit Signal Output (UT323 and
UT325 only), Normal Temperature Compensation,
Debug (UT323 and UT325 only)

N/A Yes

N/A Yes

One piece of 9V (NEDA1604 or 6F22 or 006P)

Sampling Rate

Time

Data Store

Setup

Over Limit Alarm

Over Limit Signal

Power

Accuracy is specified for ambient temperatures between 18ºC(60ºF)and 28ºC
(82ºF) for a period of 1 year, operating temperatures: -10ºC ~ 50ºC (14ºF ~
122ºF) . Th e above specifications do notinclude thermocouple probe error.

* END *

This operating manual is subject to change without notice.

6. The Max.value for high alarm is the upper limit value of measuring range of
the applied thermocouple.

7. The Min. value for high alarm is the setting low alarm limit value if low alarm
is enabled (if still less than the low alarm limit value, Min. Value=Low Alarm
Limit Value+1), otherwise this Min. value is the lower limit value of measuring
range of the applied thermocouple.

3. With High/Low Limit Alarm set up and Over Limit Signal Output turned on
already,

The display shows On or Off. It defaults to ON status at power-on.

defaults to OFF status.

backlight on.

sources the voltage corresponding to

ENTER

RCL shows and blinks on LCD.

last stored reading prior to exiting the logging. The temperature unit will
switch automatically along with the recalled data based on what have been
stored during the logging.

location reaches 99.

shows the system time when the data was logged. The primary display shows
each logged reading.

3.

4.