Instruction Manual
UT381/382 Instruction Manual
UT380 Series Product Introduction
II Unpacking Inspection
III Safety Instruction
IV Meter Structure
V Setting and Operation of Meter
VI Specifications
VII Maintenance
UT381/382 Instruction Manual
I UT380 Series Product Introduction
UT380 series luminometer has two models: UT381 and UT382. UT380 series
luminometer is a kind of digital meter applying high-precision digital visible light
sensor and 8-bit microprocessor processing data.
Illuminance: Illuminance means the luminous flux received on each unit area
of illuminated object, with adopted unit of foot candle (12 inches make 1foot)
in Britain and USA and meter candle in Europe. 1 foot candle means the
illuminance received on the surface from the direct 1 candle light source with 1
foot away from the illuminated surface, abbreviated as FC. In the same way, 1
meter candle means the illuminance received on the surface from the direct 1
candle light source with 1 meter away from the illuminated surface, abbreviated
as Lux. UT380 series can test illuminance within 0~20,000Lux, and UT382 can
be connected with PC to realize real-time data storage and analysis, and the data
recorded in luminometer can be transmitted to PC to analyze, print and record,
UT381/382 Instruction Manual
II Unpacking inspection
Unpack and check, if there is any damage or loss, contact with the nearest local
sales service agency
1. Mainframe
2. Instruction manual
3. USB testing line (only for UT382) 4. Software disc(only for UT382)
5. 9V battery
6. Sensitive mirror cap
1 unit
1 copy
1 piece
1 piece
1 piece
1 unit
UT381/382 Instruction Manual
III Safety Instruction
potential operation and condition which are dangerous or factors which
may cause damage to the luminometer are indicated in following context!
Motion or status with potential harm to users or the factors having possible
damage on illuminometer will be identified as below.
Please use the luminometer according to the instructions, or the luminometer
damage or personal injury may be caused. In order to avoid luminometer damage
and personal injury, please operate according to following instructions.
● Check if luminometer shell is broken or any part loss before using. Do not
use the meter if it is damaged.
● When battery indicating sign “
” appears, please replace battery as soon
as possible to avoid measured data error.
● When the luminometer work abnormally, do not use it, and please send it to
the designated maintenance center of our company for repair by professional
service man.
UT381/382 Instruction Manual
● Please do not use it in the place adjacent to explosive gas, steam and dust.
● Do not dismantle the shell of luminometer without authorization to avoid
luminometer damage.
● Do not charge the battery to avoid battery explosion and personal injury.
Please pay attention to the “+” and “-” of the battery during installing.
● Especially keep the sensitive mirror clean and away from scratch, cover it
with cap after completing measurement.
UT381/382 Instruction Manual
IV Meter Structure
1. Meter structure (Figure 1,Table 1)
Sensitive mirror
Display screen
Table 1
Figure 1
UT381/382 Instruction Manual
2. Signs (Figure 2, Table 2)
Figure 2
Auto range sign
Minimum value display sign
Maximum value display sign
HOLD Data hold sign
Main display
FULL Full storage display sign
Auto power off sign
USB communication (UT382 only)
Low voltage sign
LoadNo record number
Secondary display
Data record storage sign
nstruction of “reading ×10”
Illuminance unit (Lux)
Illuminance unit (Britain and USA)
Table 2
UT381/382 Instruction Manual
3.Keys description (Figure 3 )
Figure 3
UT381/382 Instruction Manual
1. Power on/off key: long press to power on, shot press to power off.
2. Unit selection key: under measuring state, press this key to switch the unit of
reading between Lux and FC
3. Maximum value and minimum value selection key: under measuring state, press
the key to switch between normal measurement, MAX and MIN in order of
normal measurement→MAX →MIN. When “MAX” or “MIN” sign is displayed
on LCD, the luminometer just displays the maximum reading value or the
minimum reading value.
4. Auto range and Manual range selection key: in auto range state, press the key to
enter manual range state; press once again to enter low range and high range
one by one; long press the key to return to auto range state.
5. Data memory and delete key: press this key to save measured data automatically
or manually, the biggest storage capacity: 2044 pieces; press this key and power
on the meter at the same time, you can delete the recorded data.
6. Menu key: long press this key to enter the function setting mode; short press this
key again to enter next function in order of USB/APO/SEC/CODE/DEF?/ normal
measurement; press HOLD key to exit menu mode.
7. Data hold key: press this key to lock the measured data display on LCD, and
display “HOLD” sign at the same time; press this key again to exit hold function.
UT381/382 Instruction Manual
V Setting and Operation of Meter
1. Auto power off: power off in about 10 minutes automatically
● Auto power off or not selection setting function: long press “MENU” to enter
function selection menu, and then short press it to select “APO.0” or “APO.1”
interface, and then press “RANGE/+” or “MAX/MIN/-” key to switch between
“APO.0” and “APO.1”; press “MENU” key to enter next function setting or
press “HOLD” key to exit function setting, and luminometer will record the
updated settings.
● Under the state that “APO.0” is selected, auto power off function is closed,
namely, the meter won’t be power off automatically; under the state that
“APO.1” is selected, auto power off function is selected, and the auto power
off sign is displayed on the screen at the same time. After power off, the
luminometer will record the settings which will be restored after it is power on,
it is unnecessary to set up again at each time.
2. Data memory and delete: auto and manual data memory
● The interval of auto data memory is within 0.5-255 seconds, which is
adjustable; long press “MENU” to enter function selection menu, and then
UT381/382 Instruction Manual
short press it to select SECREC interface, while the auto memory interval is
displayed on the main display; press “RANGE/+” or “MAX/MIN/-” key to adjust
the auto memory interval displayed on the main display; press “MENU” key to
enter next function setting or press “HOLD” to exit function setting. And
luminometer will save the updated settings.
Long press “REC/ERASE” to save data automatically, and “REC” sign
displayed on LCD SECREC flashes, and the luminometer will save the
measured data according to the current auto saving interval setting; if the
storage space of luminometer is fully taken up, the system will exit auto
memory; and “FULL” sign will be displayed on LCD; press “REC/ERASE” key
to exit auto data memory function.
Manual data memory: in the normal measurement state, press “REC/ERASE”
once to save one measured data, and “REC” sign displayed on LCD
SECREC flashes once.
When 2044 pieces of data is fully recorded, “FULL” sign will be displayed on
LCD, and no data can be saved at this moment. When the saved data is
above 2044 pieces
Under power-off state, press “REC/ERASE” and power on meanwhile, when
“CLR” sign is displayed on LCD, all saved data will be cleared.
UT381/382 Instruction Manual
3. View saved data:
● Short press “MENU” to enter view recorded data function; if there is no
data record in the luminometer, “----” sign will be displayed on both LCD
main display and secondary display, and the luminometer will return to normal
measurement state in about 0.5 seconds; If there a certain data records in
the luminometer, the total number of current data records will be displayed on
LCD secondary display, and the value of the last piece of data will be
displayed on the main display.
● After entering option of view recorded data, press “UNIT” to view the 1st
piece of recorded data; press “RANGE/+” and “MAX/MIN/-” keys to view data
records forward or backward; press “HOLD” key once and then your reading
will jump over 100 pieces of record forward, when there isn’t over 100 pieces
of record after current record, press this key to return to the 1st record.
● The luminometer can store 2,044 pieces of records at most.
4. Restore to factory defaults:
● Long press “MENU” key to enter function setting, and then short press this
key to select restore to factory defaults, and “DEF?” sign will be displayed on
the LCD and flashes, at this moment you can press “HOLD” to restore to
factory defaults; press “MENU” or “REC/ERASE” key, you can exit restore to
UT381/382 Instruction Manual
factory defaults.
● After restoring to factory defaults, the defaulting state of the system is: USB.0
(no USB transmission); APO1 (auto power off); 60S (auto record interval is
set up as 60s); clearing all data records.
5.USB data transmission function: (only for UT382, see Figure 4)
● Long press “MENU” to enter USB transmission setting, and “USB.0” or
“USB.1” will be displayed on LCD; USB.0 means that data can’t be
transmitted; “USB.1” means that data can be transmitted; press “RANGE/+”
or “MAX/MIN/-” key to switch between “USB.0” and “USB.1”.
● Each time, after the system is power on, the USB function of the luminometer
is set as “USB.0” (no data transmission state) automatically.
● The communication between luminometer (UT382) and PC is realized
by USB data transmission, thus PC must have USB port, see Picture 4 for
luminometer and PC connection.
● When connecting UT382 to the computer, it cannot operate any functional
buttons during transmission.
UT381/382 Instruction Manual
Figure 4
UT381/382 Instruction Manual
6. Illuminance measuring
● In process of measuring illuminance, the sensitive mirror must be
perpendicular to the measured illuminating source to ensure accuracy of
measured data..
● If distance between measured illuminating source and illuminometer,
positions or different of them, or the environment is different, then the
measured data will be different; cause, the intensity of light varies with
change of distance, position, angle and environment. Since the intensity
of light will be varied with its distance, position, angle and surroundings to
illuminometer, measured date will be different accordingly.
● Make sure there is no scratch or dirt on sensitive mirror of luminometer, or
the measured data won’t be accurate.
● When the illuminance exceeds the measuring range of the luminometer, “OL”
sign will be displayed.
● After completing measuring, cover the sensitive mirror with cap to avoid
scratch on sensitive mirror and keep it clean.
UT381/382 Instruction Manual
VI Specifications
1. General specification
● LCD: 3 1/2-bit display, 1999-bit at most
● Over range display: “OL”
● Low voltage display:
● Type of sensor: digital visible light sensor
● Sampling rate: 100 times/s
● Power supply: one 1604A 6F22 9V battery
● Battery life: 200 hours for typical battery (alkaline battery)
● Dimensions: 195mmx 45mmx 26m
● Weight: about 185g (including battery)
2. Environment limit
● Indoor use
● Safety standards: EN61326: 2006;
EN55022: 1998+A1+A2;
EN55024: 1998+A1+A2
● Pollution grade: grade 2
UT381/382 Instruction Manual
● Operating temperature and humidity:
0℃-30℃ (no more than 80%RH);
30℃-40℃ (no more than 75%RH);
40℃-50℃ (no more than 45%RH)
● Storage temperature and humidity: -20℃-+60℃ (no more than 80%RH)
3. Electrical specification
● Accuracy tolerance: ± (a%reading +b digits), calibrate once each year
● Environment temperature: 23℃±5℃
● Environment humidity: ≤80% RH
● Temperature coefficient: 0.1× (accuracy tolerance)/℃
UT381/382 Instruction Manual
Illuminance measuring
Resolution Accuracy tolerance: ± ( a %reading +b digits)
± (3% + 20)
± (3% + 8)
± (3% + 8)
± (3% + 8)
The accuracy tolerance of FC can
be verified by unit conversion:
FC=10.76lux, if accuracy tolerance
verification is needed, it can be
achieved by unit conversion.
UT381/382 Instruction Manual
VII Maintenance
During replacing battery or measuring, keep the sensitive mirror from scratch or
dirt to avoid damaging the mirror or influencing the measuring precision; and do
not charge the replaced battery to avoid explosion and safety accident!
1. Battery installation and replacement
When “
” is displayed on the luminometer, replace the battery immediately.
Replace the battery by following procedures:
● Power off
● Loosen the screw of battery cover and take it off.
● Replace with a new 6LF22 9V 1604A battery, please use battery with the
same model, and do not use unauthorized battery.
● Pay attention to the anode “+” and the cathode “-”. After completing
installation, install the cover and tighten the screw.
2. General maintenance
● When the surface of luminometer is dirty, clean with wet cloth and neutral
UT381/382 Instruction Manual
detergent, grinding miller and solvent are forbidden.
● When the luminometer is damaged and needs to be repaired, please send it
to the designated maintenance center of our company for repair by
professional service man, do not repair it without authorization.
● Especially in the process of using, keep the sensitive mirror of luminometer
away from scratch or dirt to avoid damaging the mirror or influencing the
measuring precision.
● Remove the battery if it won’t be used for a long time.
● Store the luminometer in a place free of moist, high temperature and strong
magnetic field.
Specifications and other information shown on this instruction manual are subject
to change without notice