Major tech MT975 User manual

INSTRUCTION MANUAL
MT975
SOUND LEVEL METER

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1. SAFETY INFORMATION
Read the following safety information carefully before
attempting to operate or service the meter.
Use the meter only as specified in this manual:
Environment conditions
①Altitude lower than 2000 meters
②Relatively humidity ≤90％RH
③Operation Ambient 0 ~ 40°C
Maintenance & Clearing
①Repair or servicing are not covered in this manual
and should be performed by a technician.
②Periodically wipe the case with a dry cloth. Do not
use solvents or eradicator on this instrument.
Safety symbols
Comply with EMC
2. FUNCTIONS DESCRIPTION
This Sound Level Meter is designed for noise project;
quality control; illness prevention and cure and all kinds of
environmental sounds measurement. It is applied to the
sounds measurement at factory; school; office; traffic
access and household, etc.
This unit confirms to the IEC61672-1 CLASS2 for
Sound Level Meters.
MAX & MIN measurements
Over range display

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Under range display
A & C Weighting
FAST & SLOW response
Analog AC/DC outputs for connection to frequency
analyzer or X-Y shaft recorder
3. SPECIFICATION
Standard applied: IEC61672 -1 CLASS2
Accuracy:±1.4dB
Frequency range:31.5HZ ~ 8KHZ
Dynamic range:50dB
Memory:32700
Level ranges: LO:30dB~80dB
Med:50dB~100dB
Hi:80dB~130dB
Auto:30dB~130dB
Frequency weighting: A/C
Time weighting: FAST ( 125ms ), SLOW ( 1s )
Microphone: 1/2 inch electret condenser microphone
Display: 4 digits LCD display with a resolution of 0.1dB
Display Update: 2 times/sec.
MAX hold: Hold the Maximum reading
MIN hold: Hold the Minimum reading
HOLD: Hold the readings
Alarm function: “OVER”is when input is more than upper
limit of range.“UNDER”is when input is
less than lower limit of range.
Analog output:AC/DC outputs from earphone outlet
AC=1Vrms ,DC=10mV/dB

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Data output: USB data traffic
Auto power off:Meter automatically shuts down after
approx. 15 minutes of inactivity.
Power supply: One 9V battery, 006P or NEDA1604 or
IEC 6F22.
Power life:About 30hours
Operation temperature and humidity:
0°C~40°C,10％RH~90％RH
Storage temperature and temperature:
-10°C ~+60°C，10％RH~75％RH
Dimension:278 (L) x 76 (W) x 50(H) mm
Weight : 350g
Accessories: Instruction manual, battery, screwdriver,
￠3.5mm earphone plug, windscreen,
software, USB cable.
4. NAME AND FUNCTIONS
①Windscreen
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13
14
15
16
17
18
DC 9V
OUTPUT
CAL
REC
FAST
A/C
1
2
3
4
5
8
6
7
10
9
11

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②LCD：
SYMBOL FUNCTION
LCD 4 digits
MAX Maximum hold
MIN Minimum hold
OVER over range
UNDER under range
FAST Fast response
SLOW Slow response
dBA A-Weighting(responseto human sense)
dBC C-Weighting(response to machine monitor)
30—130 Range indicate
REC Recording data into computer
AUTO Auto level range selection
FULL Memory full
HOLD Data hold function
AutopoweroffPress the ”SETUP“ button to
disable power off
Low battery indicate

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③REC button
3.0 DATALOGGER function
Press “REC” button once the power has been switched on,
the display will show “REC” to start Data Recording，press
the button again to exit the record (Note: In order to avoid
data error, please don’t power it off under REC condition,
when the REC function is deleted then it can power off).
3.1 Adjusting DATALOGGER response
Press the button continuously before power it on，then
press ,it will be displayed as following: Press ’LEVEL’
button to adjust memory time,press ‘HOLD’ button to hold
the setup；
3.2 Data zero function
Select the button continuously before power it on，loosen the
button when the display showing’CLR’ after the meter
power on,which indicates that the data in DATALOGGER
has been deleted.
④SETUP button
4.0. The time chip adjustment

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Press‘SETUP’button and then power it on，when‘TIME’
symbol displays then loosen‘SETUP’， the meter will be
under time adjustment mode，at the time the display will
show the date as following:
Select the‘SETUP’button for a second time, the ‘hour
adjustment mode will be displayed：
Select ‘LEVEL’ to save the adjustment. Press the ‘HOLD’
function to save the setup;
Press the ‘SETUP’ button for a third time, the ‘hour’
adjustment mode will be displayed:
Press
(h-P =P.M,h-A=A.M)
‘LEVEL’ to make the adjustment，press‘HOLD’to save the
setup；

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Press the‘SETUP’button for a fourth time, the ‘date’
adjustment mode will be displayed
Press
‘LEVEL’ to make the adjustment，press ‘HOLD’ to keep the
setup；
Press the ‘SETUP’ button for a fifth time, the ‘month’
adjustment mode will be displayed：
Press
‘LEVEL’ to make the adjustment，press ‘HOLD’ to save the
setup；
Press the ‘SETUP’ button for a sixth time, the ‘year ’
adjustment mode will be displayed:
Press
‘LEVEL’ to make the adjustment，press ‘HOLD’ to save the
setup:
Press the ’SETUP’ button for a seventh time, the ‘time’

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adjustment mode will be displayed:
Press ‘HOLD’ to save the setup. The time and date will
return to the factory setup once the battery is flat or needs to
be replaced, if the time can’t be adjusted, initialize the time
chip first.
4.1. USB communications setting:
Turn on the meter, connect the unit to the computer. Select
the software COM3（COM4）. Press ‘SETUP’ and will
disappear from the display to indicate and disable auto
power off, that the USB data will start transmitting.
⑤FAST/SLOW button:
Time weighting selection
FAST: fast sampling measurement, 1 time per 125mS.
SLOW: slow sampling measurement, 1 time per second.
⑥MAX/MIN button:
Select the Maximum and Minimum hold button for once to
enter the MAX/MIN measurement, ‘MAX’ will be displayed
on the LCD screen. Maximum sound level will be captured
and held a until higher sound level is captured. Press the
button again, ‘MIN’ will appear on the LCD screen and the
minimum sound level will be captured and held until a
lower sound level is captured. Press the button one more

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time to exit MAX/MIN measurement.
⑦LEVEL button: Level range selection
Each time you press “LEVEL” button, the level range will
change between ‘Lo’ level, ‘Med’ level, ‘Hi’ level and ‘Auto’
level in that sequence.
⑧Backlight button
8.0．Turn the backlight on/off
8.1．DATALOGGER response setting;
Press the button continuously until‘INT’symbol appears.
Press‘LEVEL’to set up the data memory response and
press‘HOLD’to savethe setting.
⑨Frequency weighting select button
A：A-Weighting
C：C-Weighting
⑩HOLD button:
Press “HOLD” button, The hold function freezes the
reading in the display.
⑾Power button