Morris 57074 User manual

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RS232
uAmA
OFF
ON
RANGE
10A
mV
V
V
DC
AC
SELECT
AUTO
OFF
1000V
Hz
V
COM
1000V
700V
uA
mA
A
RS232
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LIGHT
DUTY
ON
%
Hz
mF
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A
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HOLD
Hz
°C
REL
CAT III
3 3/4 Digit Multimeter
Model 57074
Users Manual

Table of Content
Introduction ………………………………………………………………………………………….. 1
Unpacking and Inspection ………………………………………………………….………….… 2
Safety Precautions …………………………………………………………………….……………. 2
A Quick Tour …………………………………………………………………………….………….… 2
Symbol Explanation …….…………………………………………………………………….… 6
Instrument Layout ……………………………………………………….………….…………… 7
Functions of Keys ……………………………………………………………….…….………… 9
Others …………………………………………………………………………………..……….. 11
Making Measurements ……………………………………………………………………………. 13
Measuring AC or DC Volts …………………………………………………………..……….. 13
Measuring DC or AC Current …………………………………………………………….… 14
Measuring Resistance ………………………………………………………………………… 16
Measuring Capacitance …………………………………………………………………..…… 18
Measuring Frequency and Duty ……………………………………………………………. 19
Measuring Temperature ……………………………………………………………..………… 20
Testing Diode ……………………………………………………………….………………… 21
Testing Continuity ………………………………………………………………….………… 22

Specifications ………………………………………………………..……..…………………… 23
General Specifications ……………………………………………………………...………… 23
Accuracy and Resolution ……………………………………………………………………… 24
Maintenance …………………………………………………………………..…………………… 28
Replacing the battery ………………………………………………………….……………… 28
Replacing the Fuse ……………………………………………………………..…………… 29
Others …………………………………………………………………………………………… 30
RS232C serial data output ……………………………………………….……………………… 30

3 3/4 Digit Multimeter
Users Manual
- 1 -
Introduction
This is a high performance, low power consumption and 3 3/4 digits (4000 Counts)
mutimeter. The meter is made with a large integrated circuit. Includes manual and auto range
and all functions and ranges are protected for overload. Measures AC/DC voltage, AC/DC
current, resistance, diode, continuity, capacitance, frequency, duty and temperature.
Unpacking and Inspection
Unpacking and removing the meter. If parts are missing or damaged, please contact the
distributor.
Multimeter 1
User manual 1
Test leads 1
Thermocouple 1
RS232C interface 1
Software CD 1

3 3/4 Digit Multimeter
Users Manual
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Safety Information
The meter has been designed according to IEC1010-1 concerning safety requirements for
electrical measuring instruments with an over voltage category (1000V CAT.Ⅲ) & pollution 2.
WARNING:
READ “SAFETY INFORMATION” AND “WARNING
INFORMATION” BEFORE USING THIS MULTIMETER!

3 3/4 Digit Multimeter
Users Manual
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Safety Precautions
Injury or death can occur even with low voltages and low current. It is extremely important
that you read this safety information before using your multimeter. Follow all safety practices
and proper operating procedures for equipment being tested.
Exercise extreme caution: Measuring voltage above 20V, measuring current greater that
10mA, measuring AC power line with inductive loads, measuring AC power line during
electrical storms.
Always inspect your multimeter test leads for signs of damage or abnormality before
every use. If any abnormal conditions exist (i.e.: broken or damaged test leads, cracked
case, display not reading, etc.), do not attempt to take measurements.
Never ground yourself when taking electrical measurements. Do not touch exposed metal
pipes, outlets, fixtures, etc., which might be at ground potential. Keep your body isolated
from ground by using dry clothing; rubber shoes, rubber mats, or any approved insulating
material.
Never touch exposed wiring, connections, test probe tips, or any live circuit conductors
when attempting to make measurements.
Never replace the protective fuse inside the multimeter with a fuse other than the
specified or approved equal fuse. Replace only with same type of fuses. To avoid
electrical shock, disconnect the test leads and any input signals before replacing the
fuses.
Replace only with same type of battery. To avoid electrical shock, disconnect the test

3 3/4 Digit Multimeter
Users Manual
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leads and any input signals before replacing the battery.
Do not operate this multimeter in an explosive atmosphere (i.e., in the presence of
flammable gases or fumes, vapor or dust.).
Measuring voltage that exceeds the limits of the multimeter may damage the meter and
expose the operator to a shock hazard. Always recognize the multimeter voltage limits on
the front of meter.
Never apply more than 1000 DCV or 700ACV between the COM jack and earth ground.
Never touch a voltage source when the test leads are plugged into a current jack.
When testing for the presence of voltage or current, make sure the voltage or current
ranges are functioning correctly. Take a reading of a known voltage or current before
assuming a zero reading indicates no current or voltage.
Do not attempt calibration or service unless trained and another person capable of
rendering first aid and resuscitation is present.

3 3/4 Digit Multimeter
Users Manual
- 5 -
A Quick Tour
1. Symbol Explanation
Attention! Low Battery
Dangerous Voltage! Fuse
Ground European union
directives
AC Double Insulation
DC

A Quick Tour
Instrument Layout
- 6 -
2. Instrument Layout
①.LCD
②.Keys: select measuring function
③.Function/Range selector rotary switch
④.10A input terminal: This is positive input terminal
for measuring 10A current, which connect with the
red test lead.
⑤.μA/mA/°C input terminal: This is the positive
input terminal for measuring 400mA current and
temperature, which connect with the red test lead.
⑥. COM input terminal: This is the negative input
terminal for all measurement modes, which connect
with the black test lead.
⑦.Hz/V/Ωinput terminal: This is the positive input
terminal for voltage, resistance, duty, frequency,
capacitance, diode and continuity, which connect with the
red test lead.
700V
1000V
1000V
CAT II
ON
OFF
COM
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VHz
uAmA10A
RS232
ON
OFF
V
V
mV
Hz
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uA
mA
A
DUTY LIGHT
SELECT Hz HOLD
RANGE
AUTO
AC
DC
RS232
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AV
F
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Hz
REL
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3 3/4 Digit Multimeter
Users Manual
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3. Keys Function
SELECT (Function Switch): Select is the function selecting key that acts with trigger. Use
the key as measuring functions select.
RANGE (Auto/Manual Range): This key is the auto/manual key. Power on default is auto
measurement, and press one time to switch to the manual measurement. In manual
measurement mode, the system will jump up one mode for each press until the highest
mode, then return to the lowest mode as a loop. If you press the key over 2 seconds, the
system will switch back to auto measurement status. Frequency and capacitance
measurement cannot use manual measurement.
REL (Relative Value Measurement): Rel key is the relative value measurement key.
Except Hz/Duty, Diode and Continuity, other functions can do the relative value
measurement.
Hz/DUTY (Frequency/Duty Cycle): Hz/Duty is the frequency/Duty Cycle select key. In
frequency measurement mode, press the key can select frequency or duty cycle
measurement mode; in AC/DC voltage or AC/DC current mode, press the key can
proceed to voltage, Frequency, Duty cycle or Current, Frequency, Duty cycle
measurement mode select.

3 3/4 Digit Multimeter
Users Manual
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HOLD/LIGHT (Reading Hold/Back Light): Hold/BL key is the reading bold/back light
control key. Press the key, the display value will be locked and unchanged.
Press the key again, the locked status will be erased and enter the normal measurement
status. When pressing and holding the key over 2 seconds, the backlight will be on. In the
backlight on status, press the key over 2 seconds, the backlight will be off.
POWER: power on or off.
RS232: serial data output on or off.

3 3/4 Digit Multimeter
Users Manual
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4. Other Functions
Auto power off: In the process of measuring, using the function key or switch, if there is
no any action on them within 30 minutes, the meter will auto power off (standby mode). In
auto power off status, press the function key or switch, the meter will be auto power on
(operating mode). Press and hold the SELECT key to turn the system on, the auto power
off function will be cancelled. And in RS232 operation mode, the auto power off function
will be cancelled.
Buzzer: Press any key or turn any function switch, the buzzer will raise one sound
(approx. 0.25 second to 1second). In the continuity measuring status, if the resistance is smaller
than50 Ω , the buzzer will sound.
Serial data output: The meter has the serial data output function. When the meter is
connected with the computer interface, it can output the measuring data for recording,
analyzing, processing and printing the measuring results.

Making Measurements
MeasuringAC or DC Voltage
- 10 -
Making Measurements
1. Measuring AC or DC Voltage
a) Turn the rotary switch to ACV or DCV or DCmV range.
b) Insert the black and red test leads into the COM and VΩHz input terminal.
c) Connect the test lead tips in parallel with the circuit to be measured. And don’t touch
any electrical conductors.
d) Press Hz/Duty key one times then meter enter measuring frequency status; press it
again then meter enter measuring duty status; press it three times then meter return
measuring voltage status.
e) Read the result directly from LCD.
WARNING:
Can’t measure higher than 1000V DC or 700V AC.
When measuring high voltage, don’t get electric shock.
After measuring completely, disconnect the test leads from the circuit being
measured.

3 3/4 Digit Multimeter
Users Manual
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2. Measuring AC or DC Current
a) Turn the rotary switch to μA, mA or Arange. Power on default is DC measurement,
press one time SELECT key to switch to AC measurement.
b) Insert the red and black test leads into the μAmA or A and COM input terminal.
c) Connect the test lead tips in serial with the circuit to be measured. And don’t touch
any electrical conductors.
d) Press Hz/Duty key one time then enter measuring frequency status; press it again
then enter measuring duty status; press it three times then enter return measuring
voltage status.
e) Read the result directly from LCD.
WARNING:
Can’t measure higher than 10A in 10A range; and can’t measure higher than
400mA in μA or mA range, otherwise the fuse will blowout.
Measurement time must be fewer than 10 seconds for each measurement, and
the interval time for continuous use should be less than 15 minutes.
After measuring completely, disconnect the test leads of the circuit measured.

Making Measurements
Measuring Resistance
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3. Measuring Resistance
a) Turn the rotary switch to the Ωrange.
b) Insert the black and red test leads into the COM and VΩHz input terminal.
c) Connect the test lead tips in parallel with the circuit to be measured. And don’t touch
any electrical conductors.
d) Read the result directly from LCD.
WARNING:
Before measuring resistance in circuit to be sure power off; and to be sure that
capacitor has been discharged fully.
For measuring resistance above 1MΩ, the meter may take a few seconds to get
a stable reading. This is normal for high resistance measurements.
Any voltage present during a resistance measurement will cause inaccurate
readings and could damage the meter if exceeding the overload protection of
250V.
After measuring completely, disconnect the test leads of the circuit being
measured.

Making Measurements
Test Diode
- 16 -
4. Measuring capacitance
a) Turn the rotary switch to the capacitance range.
b) Insert the black and red test leads into the COM and VΩHz input terminal.
c) Connect the test lead tips in parallel with the circuit to be measured. And don’t touch
any electrical conductors.
d) Read the result directly from LCD.
WARNING:
Before measuring capacitance in circuit to be sure power off
Before measuring capacitance be sure that it has been discharge fully.
After measuring completely, disconnect the test leads with the circuit
measured.

Making Measurements
Test Diode
- 16 -
5. Measuring Frequency and Duty
a) Turn the rotary switch to the Hz range.
b) Insert the black and red test leads into the COM and VΩHz input terminal.
c) Connect the test lead tips in parallel with the circuit to be measured. And don’t touch
any electrical conductors.
d) At measuring frequency status, press Hz/Duty one time then meter enter measuring
duty status; press it again & then return measuring frequency status.
e) Read the result directly from LCD.
WARNING
Determine that the amplitude level of the signal to be measured is not greater
than the input voltage limit (60V).
After measuring completely, disconnect the test leads with the circuit
measured.

Making Measurements
Test Diode
- 16 -
6. Measuring temperature
a) Turn the rotary switch to the temperature range.
b) Insert the Thermocouple into the COM and μAmA input terminal.
c) Put the Thermocouple’s other side on the object to be measured.
d) Read the result directly from LCD.
WARNING
The meter will display temperature inside meter, if no thermocouple.
Don’t enter other signal.

Making Measurements
Test Diode
- 16 -
7. Test Diode
a) Turn the rotary switch to the Ωrange.
b) Insert the black and red test leads into the COM and VΩHz input terminal, and press
SELECT key to select diode status.
c) Connect the test leads tip in parallel with the diode to be measured.
d) Read the result directly from LCD.
WARNING:
If the diode is reversing biased or there is open circuit, the reading will display
“OL”.
Before measuring diode in circuit to be sure power off; and to be sure that
capacitor has been discharge fully.
After measuring completely, disconnect the test leads with the circuit
measured.

3 3/4 Digit Multimeter
Users Manual
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8. Test Continuity
a) Turn the rotary switch to the Ωrange.
b) Insert the black and red test leads into the COM and VΩHz input terminal; and press
SELECT key to select continuity status.
c) Connect the test lead tips in parallel tow point at the circuit, if the resistance is less
than 50Ω, the buzzer will sound.