Major tech MT870 User manual

MT870
True RMS Digital Multimeter
INTRODUCTION
The MT870 multimeter is a slim sized, portable, robust drop proof digital
multimeter. The MT870 has a 2000 count digit LCD monitor with large 25mm
digits that offer clear and easy reading. The circuitry design is centred on
large-scale IC A/D converters in conjunction with an over-load protection
circuit, the meters offers excellent performance and is ideal for a handy
digital multimeter.
The meters can be used to measure DC & AC True RMS voltage, DC & AC
True RMS current, resistance, battery test, diode test and audible continuity.
If the equipment is used in a manner not specified by the manufacturer, the
protection provided by the equipment may be impaired.
This Equipment Conforms to UL STD. 61010-1, 61010-2-030 and 61010-2-
033; Certified to CSA STD. C22.2 NO. 61010-1, 61010-2-030 and 61010-2-
033.
1. LCD display: 3 1/2 digits LCD display, full function symbol display.
2. SELECT key: This key works on the " " range, press the key to
choose diode or continuity test, on the current range, change to DC or AC.
If you press and hold the “SELECT” key to power on, “Auto Power Off ”
function will be disabled. “
3. RANGE Key: Press the “RANGE” key, the meter enters manual range
mode, press it more than 2 seconds again, return to auto mode.
4. MAX/MIN key: Press the “MAX/MIN” key to lock MAX or MIN value,
and the “MAX” or “MIN” sign will appear on the display, press it more
than 2 seconds again to exit.
5. D.HOLD key: Press the “D.HOLD” key to lock display value, and the “DH”
sign will appear on the display, press it again to exit.
6. RESET Key: Press the “RESET” key to reset the meter.
7. Rotary Switch: Use this switch to select functions and ranges.
8. COM: COM “-” Input Jack
9. 10A: 10A Input Jack
10. AΩmA: VµA, mA,/BATT/Ω/ Input Jack
11. Meter casing
12. Protective casing
Safety Information
1. The meter is designed according to IEC61010-1 concerning
electronic measuring instruments with an over-voltage
category 600V (CAT II) or 300V (CAT III) and pollution 2.
2. Follow all safety and operating instructions to ensure that
the meter is used safely and is kept in good operating
condition.
3. Safety symbols:
Important safety information, refer to the operating
manual.
Dangerous voltage may be presence.
Double insulation (protection Class II)
Special Cautions for Operation
1. The meters can be safe only according to standard p rocedures when used
in conjunctions with the supplied test leads. Please replace damaged test
leads with the same electric specifications.
2. To avoid risk of electric shock, do not use the meter if the c asing has been
opened.
3. The range switch should be right position before making a m easurement.
4. To avoid electric shock and damaging the instrument, the i nput signals
must not exceed the specified limits.
5. When measuring TV set or switched power, attention s hould b e paid to the
possible pulses that may cause damage to the circuitry.
6. Range switch position must not be changed at random d uring
measurement.
7. Take caution against shock in the course of measuring v oltage higher than
DC 60V & AC 30V.
8. Protection fuse should be replaced only with same type a nd same
specification.
9. Verity the multimeter's operation by measuring a known voltage.
10. After operation is finished, set function switch at OFF to save battery
power.
11. If the meter is without usage for long time, take out the battery to avoid
damage by battery leakage.
General Specifications
1. M ax Voltage between input terminal and Earth Ground: C AT II 600V or
CAT II 300V.
2. Over-range Indication: display “OL” for the significant digit.
3. Automatic display of negative polarity “-”.
4. Low Battery Indication: “ ” displayed.O L
5. Display: 3 1/2 digit LCD with a max. reading of 1999.
6. Auto range & manual range control.
7. Auto Power Off: When measurement exceeds 15 minutes without switching
mode and pressing key, the meter will switch to standby mode. Press any
key to exit standby mode. When restart the system, press and hold SELECT
key to disable auto power off.
8. Fuse protection: 250mA/600V Fast Fuse, 10A/600V Fast Fuse.
9. Power supply: 1.5V×2 “AA” R6P battery
10. Operating Temp.: to 40 (relative humidity <85%)0°C °C
11. Storage Temp.: -10 to 50 (relative humidity <85%)°C °C
12. Guaranteed precision Temp.: 23±5 (relative humidity <70%)°C
13. Dimension: 150 x 100 x 36mm
14. Weight: approx. 250g (including battery)
DC Voltage
Range Resolution Accuracy
200mV 0.1mV
2V 1mV
±(0.5% of rdg + 2 digits)
20V 10mV
200V 100mV
600V 1V ±(0.8% of rdg + 2 digits)
* Impedance: 10MΩ, More than 100MΩ on 200mV range
* Overload protection: 600V DC or AC rms
Range Resolution Accuracy
2V 1mV
±(0.8% of rdg + 3 digits) 20V 10mV
200V 100mV
600V 1V ±(1.2% ofrdg + 3 digits)
AC Voltage
* AC True RMS
* Impedance: 10MΩ
* Overload protection: 600V DC or AC rms
* Frequency Range: 40 to 2kHz
Range Resolution Accuracy
200μA 0.1μA
2000μA 1μA±(1.2% of rdg + 2 digits)
20mA 10μA
200mA 100μA
2A 1mA
±(2.0% of rdg + 3 digits)
10A 10mA
DC Current
* Overload protection: 250mA/600V Fast Fuse10A/600V
Fast Fuse, 10A up to 10 seconds
Testing Specifications
°C °CAccuracy is specified for a period of year after calibration and at 18 to 28
°F °F(64 to 82 ) with relative humidity to 70%.
Panel Layout
1
2
3
4
5
6
7
8
910
11
12

Range Resolution Accuracy
200Ω 0.1Ω ±(1.0% of rdg + 3 digits)
2kΩ 1Ω
20kΩ 10Ω
±(1.0% of rdg + 2 digits)
200kΩ 100Ω
2MΩ 1kΩ
20MΩ 10kΩ ±(1.5% of rdg + 3 digits)
Resistance
* Overload protection: 600V DC or AC rms
Range Accuracy Load current Resolution
±(5.0% of rdg + 5 digits)
Approx. 50mA 1mV
Approx. 10mA 10mV
Battery Test
* Overload protection: 250mA/600V Fast Fuse
Diode and Audible continuity test
Range Description Test Condition
Display read approximately Forward DC current
forward voltage of diode approx. 0.5mA
Reversed DC voltage
approx. 2.2V
Built-in buzzer sounds if Open circuit voltage
resistance is less than 50Ω approx. 2V
* Overload protection: 600V DC or AC rms
Operating Instructions
Attention before operation
1. Check battery. When the battery voltage drops below a p roper
operation range, the “ ” symbol will appear on the LCD display .
and the battery needs to be replaced.
2. Pay attention to the “ ” besides the input jack which shows t hat .
the input voltage or current should be within the specified value.
3. The range switch should be positioned to desired range for
measurement before operation.
Measuring DC & AC Voltage
1. Connect the black test lead to COM jack and the red to VΩmA j ack.
2. Set the rotary switch at the desired “V ” range position, it .
shows symbol for testing DC voltage, if you want to test AC
voltage, push “SELECT” button switch.
3. Connect test leads across the source or load under measurement.
4. You can get the voltage reading from LCD. The polarity of t he red
lead connection will be indicated along with the DC voltage value.
Note:
1. “ ” means you can't input the voltage more than 600V, . .
it's possible to show higher voltage, but it may damage the
inner circuit.
2. Be cautious against shock when measuring high Voltage.
Measuring DC & AC Current
1. Connect the black test lead to COM jack and the red to the
VΩmA jack for a maximum 200mA current , for a maximum
2A or 10A current, move the red lead to the 10A jack.
2. Set the rotary switch at the desired “uA ” & “mA ” & . .
“A ” range position, it shows symbol for testing DC current, if .
you want to test AC current, push “SELECT” button switch.
3. Connect test leads in series with the load under m easurement.
4. You can get the amperage reading from LCD. The polarity of the red lead
connection will be indicated along with the DC current value.
Note:
1. When the value scale to be measured is unknown b eforehand, set the
range selector at the highest position.
2. When only “OL” is displayed, it indicates over-range situation and the
higher range has to be selected.
MAJOR TECH (PTY) LTD
T9 Industrial Village, Sam Green Road, 7
Tunney Ext. 9, , Elandsfontein
South Africa
P.O. Box 888, Isando 1600,
South Africa
Telephone: [phone]
National Contact Number: 08 61 62 5678
Sales Facsimile: [phone]
Admin Facsimile: [phone]
E-mail: [email protected]
www.major-tech.com
3. “ ” means the socket mA's maximum current is 250mA and 10A's maximum .
current is 10A, over 250mA or 10A current can be protected by the fast fuse.
4. On the 10A range, the measuring time should be less than 10 seconds to
prevent precision from affecting by circuit heating.
Measuring Resistance
1. Connect the black test lead to COM jack and the red to VΩmA jack.
2. Set the rotary switch at the desired “Ω” range position.
3. Connect test leads across the resistance under measurement.
4. You can get the resistance reading from LCD.
Note: Max. input overload: 600V rms<10sec
1. For measuring resistance above 1MΩ, the meter may take a few seconds to
stabilize.
2. When the input is not connected, i.e. at open circuit, the figure 'OL' will be
displayed for the over-range condition.
3. When checking in-c ircuit r esistance, be sure the circuit under t est has a ll
power removed and that all capacitors have been fully discharged.
Battery Testing
1. Connect the black test lead to COM jack and the red to VΩmA jack.
2. Set the rotary switch at the desired “ ” or “ ” range position to test . .
1.5V or 9V battery.
3. Connect the red test lead to the positive of the battery and the black test
lead to the negative of the battery.
4. You can get battery voltage reading from LCD.
Diode & Audible continuity Testing
1. Connect the black test lead to COM jack and the red to VΩmA jack.
2. Set the rotary switch at the “ ” range position, push “ SELECT” t o .
choose Diode or Audible continuity measurement.
3. On diode range, connect the test leads across the diode under
measurement, display shows the approx. forward bias voltage of this diode.
4. On Audible continuity range, connect the test leads to two point of circuit,
if the resistance is lower than approx. 50Ω, the buzzer sounds.
Note:
Make sure all the power is removed and all capacitors need to be d ischarged
under this measurement.
Battery replacement
1. When the battery voltage drops below the proper operation r ange t he “ ” .
symbol will appear on the LCD display and the battery need to replaced.
2. Before replacing the battery, set the selector switch to “OFF” position and
remove the test leads from the terminals. Open the cover of the battery
cabinet with a suitable screwdriver.
3. Replace the old battery with the same type of battery (AA R6P 1.5V×2).
4. Close the cover of the battery cabinet and fasten the screw.
Fuse replacement
1. This meter is provided with a 250mA/600V fast fuse to protect the battery
test and the current measuring circuits which measure up to 200mA, with a
10A/600V fuse to protect the 10A range.
2. Ensure the meter is not connected to any external circuit, set the selector
switch to “OFF” position and remove the test leads from the terminals. Open
the cover of the battery cabinet with a suitable screwdriver.
3. Replace the old fuse with the same type and rating: 6×32mm 250mA/600V
fast fuse or 6×32mm 10A/600V fast fuse.
4. Close the cover of the battery cabinet and fasten the screw.
Maintenance
1. You must replace the test leads if the insulation is broken and internal wire is
exposed, use the same test leads with the same specifications.
2. Use only a moist fabric or small amount of detergent but not chemical
solution for cleaning.
3. Do not use the meter before the back cover is properly closed and screw
secured. If any problems are encountered, stop operation immediately and
send the meter for maintenance.
4. Please remove the battery when not using for a long time.
Accessories
1. Test Leads: electric rating 600V 10A. If the test leads need to be replaced,
you must use a new one which should meet EN 61010-01 standard, rated
CAT III 600V, 10A or better.
2. Operator's Manual
Range Resolution Accuracy
200μA 0.1μA
2000μA 1μA
±(1.5% of rdg + 3 digits)
20mA 10μA
200mA 100μA
2A 1mA
±(2.5% of rdg + 5 digits)
10A 10mA
AC Current
* AC True RMS
* Overload protection: 250mA/600V Fast Fuse
10A/600V Fast Fuse, 10A up to 10 seconds
* Frequency Range: 40 to 2kHz
1.5V 9V