UNI-T UT70C Operating Manual

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Table of Contents

Title

Overview
Unpacking Inspection
Safety Information
Rules For Safe Operation
International Electrical Symbols
The Meter Structure
Rotary Switch
Functional Buttons
Display Symbols
Measurement Ranges

A. Selecting a Measurement Range
B. Manual Ranging and Autoranging

Measurement Operation

A. AC Voltage Measurement
B. DC Voltage Measurement
C. DC Milivolt Measurement
D. Measuring Continuity, Resistance,

Conductance & Capacitance
E. Testing Diodes
F. DC or AC Current Measurement
G. Frequency & Duty Cycle Measurement

MAX MIN Recording Mode
PEAK MAX MIN Mode
Operation of Hold Mode
Operation of Auto Hold Mode
The Use of Relative Value and Relative
Percentage Value Mode
Turning on the Display Backlight
Analogue Bar Graph Display
Full Icons Display
Sleep Mode
General Specifications

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Accuracy Specifications

A. AC Voltage
B. DC Voltage
C. Continuity, Resistance &
Conductance Test
D. Capacitance

E.

Diodes Test

F.

DC Current

G.

AC Current

H. Frequency & Duty Cycle

Maintenance

A. General Service
B. Testing the Fuses
C. Replacing the Battery
D. Replacing the Fuses

RS232C Serial Port

A. RS232C Port Cable
B. Setting of RS232C Serial Ports
C. System Requirements for Installing the

UT70C Interface Program

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Overview

This Operating Manual covers information on safety and
cautions. Please read the relevant information carefully
and observe all the Warnings and Notes strictly.

Warning
To avoid electric shock or personal injury, read the
"Safety Information" and "Rules for Safe Operation"
carefully before using the Meter.

Your multimeter is an intelligent digital one, a precise
instrument with a resolution of 8,000 counts and up-to­date automatic computer calibrating function. High
resolution A/D converter and micro-controller data
processing technique is adopted in the Meter, featured
with intelligence, high precision and multi-functions. The
Meter can be widely used in laboratory, field service,
domestic and other applications. All the functions and
ranges have overloaded protection.

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Unpacking Inspection

Open the package case and take out the Meter. Check
the following items carefully to see any missing or
damaged part:

In the event you find any missing or damage, please
contact your dealer immediately.

Item

1
2
3
4

5
6

7
8

Description

Operating Manual
Test Lead
Test Clip
9V Battery (NEDA1604, 6F22 or 006P)
(installed)
RS232C Interface Cable
CD-ROM (Installation Guide & Computer
Interface Software)
Holster
Tilt Stand

Qty

1 piece

1 pair
1 pair

1 piece
1 piece

1 piece
1 piece

1 piece

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Safety Information

CA T. II: Local level, appliance, PORTABLE EQUIPMENT
etc., with smaller transient voltage overvoltages than
CAT. III

CA T. III: Distribution level, fixed installation, with smaller
transient overvoltages than CAT. IV

CAT IV: Primary supply level, overhead lines,
cablesystems etc.

Use the Meter only as specified in this operating manual,
otherwise the protection provided by the Meter may be
impaired.

In this manual, a Warning identifies conditions and
actions that pose hazards to the user, or may damage
the Meter or the equipment under test.

A Note identifies the information that user should pay
attention on.

International electrical symbols used on the Meter and
in this Operating Manual are explained on page 8.

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CE Version: The Meter complies with the standards
IEC61010-1:in pollution degree 2, overvoltage category
CAT III 1000V, CAT IV 600V and double insulation .
UL V ersion: The Meter complies with the standards UL61010B-1,
in pollution degree 2, overvoltage category CAT II 1000V
and double insulation.

Rules For Safe Operation (1)

Warning
To avoid possible electric shock or personal injury,
and to avoid possible damage to the Meter or to the
equipment under test, adhere to the following rules:

l Before using the Meter inspect the case. Do

not use the Meter if it is damaged or the case

(or part of the case) is removed. Look for cracks

or missing plastic. Pay attention to the insulation

around the connectors.
l Inspect the test leads for damaged insulation

or exposed metal. Check the test leads for

continuity. Replace damaged test leads with

identical model number or electrical

specifications before using the Meter.
l Do not apply more than the rated voltage, as

marked on the Meter, between the terminals or

between any terminal and grounding.
l The rotary switch should be placed in the right

position and no any changeover of range shall

be made during measurement is conducted to

prevent damage of the Meter.
l Never working at an effective voltage over 60V

in DC or 30V rms in AC for there is danger of

electric shock.
l Use the proper terminals, function, and range

for your measurements.
l Do not use or store the Meter in an environment

of high temperature, humidity, explosive,

inflammable and strong magnetic field. The

performance of the Meter may deteriorate after

dampened.
l When using the test leads, keep your fingers

behind the finger guards.

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Rules For Safe Operation (2)

l Disconnect circuit power and discharge all high-

voltage capacitors before testing resistance,

conductance, continuity, diodes, current, or

capacitance.
l Before measuring current, check the Meter's

fuses and turn off power to the circuit before

connecting the Meter to the circuit.
l Replace the battery as soon as the battery

indicator

appears. With a low battery, the
Meter might produce false readings that can
lead to electric shock and personal injury.

l Remove test leads, RS232C interface cable and

test clip from the Meter and turn the Meter power
off before opening the Meter case.

l When servicing the Meter, use only the same

model number or identical electrical
specifications replacement parts.

l The internal circuit of the Meter shall not be

altered at will to avoid damage of the Meter and
any accident.

l Soft cloth and mild detergent should be used

to clean the surface of the Meter when servicing.
No abrasive and solvent should be used to
prevent the surface of the Meter from corrosion,
damage and accident.

l The Meter is suitable for indoor use.
l Turn off the Meter when it is not in use and

take out the battery when not using for a long
time.

l Constantly check the battery as it may leak when

it has been using for some time, replace the
battery as soon as leaking appears. A leaking
battery will damage the Meter.

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International Electrical Symbols

The Meter Structure (see figure 1)

(figure 1)

1 Front Case
2 LCD Display
3 Functional Buttons
4 Rotary Switch
5 Input Terminals

AC (Alternating Current)
DC (Direct Current)
AC or DC
Grounding
Double Insulated
Deficiency of Built-In Battery
Continuity Test
Diode
Capacitance Test
Fuse
Warning. Refer to the Operating Manual
Conforms to Standards of European Union

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mV

V

OFF

V

Rotary Switch

Below table indicated for information about the rotary
switch positions.

Rotary
Switch

Position

Function

Power is turned off.
AC voltage measurement.

DC voltage measurement.
DC millivolt measurement.

: Continuity test.
: Resistance measurement.
: Capacitance test.

Diode Test.
AC or DC Current Measurement

from 0.001A to 10.00A .
AC or DC Current Measurement
from 0.1mA to 800.0mA.

A

mA

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Functional Buttons (1)

Below table indicated for information about the functional
button operations.

Button Operation PerformedMeasuring

Function

Continuity
Test

Turn the continuity buzzer on and
off in resistance measurement
mode.

At OFF
position

At REC
mode or
REC mode
plus Hold
mode

Press while turning on the
Meter to disable the beeper at all
functions except short circuit and
diode testing.

To toggle between 100ms
response time and 1ms response
time under REC mode except at
resistance, capacitance and
continuity range.

MAX

MIN

Any rotary
switch
position
except at
conductance
mode.

Starts recording of maximum and
minimum values. Steps the
display through the sequence of
present, high (MAX), low (MIN)
and average (AVG) readings at
any mode.
In 1ms response time, it steps
through only MAX and MIN
reading.

At OFF
position

To select 1 second high accuracy
response time, press and hold
down MAX MIN while turning the
rotary switch to any function
setting.

RANGEAny rotary

switch
position

1. Press RANGE to enter the
manual ranging mode; the
Meter beeps.

2. Press RANGE to step
through the ranges available
for the selected function; the
Meter beeps.

3. Press and hold RANGE for
over 1 second to return to
autoranging; the Meter
beeps.

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HOLD Any rotary

switch
position

Press HOLD to enter and exit the
Hold mode in any mode; the
Meter beeps.

Functional Buttons (2)

Conductance
mode

Press HOLD to toggle between
conductance and resistance
value. Present resistance value
is kept.

Press to select capacitance
test.

A , mA Press to select DC or AC

current. DC is default.

At OFF
position

To disable the Sleep Mode, press

while turning on the Meter.

REL

Any rotary
switch
position

Press REL to enter and exit the

and

% mode in any measuring

mode; the Meter beeps.

Hz V , V ,

mV

, A ,

mA

1. Press Hz to enter frequency
measurement mode; the
Meter beeps.

2. Press Hz again to enter duty
cycle measurement mode;
the Meter beeps.

3. Press Hz again to return to
the last measurement mode;
the Meter beeps.

Display
Backlight

Press once to turn the Display
Backlight on and it shall shut off
automatically in around 60
seconds later.

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No. MeaningSymbol

Display Symbols (1) (see figure 2)

(figure 2)

1

The Meter is in the auto range mode in
which the Meter automatically selects the
range with the best resolution.

2

The battery is low.

Warning: To avoid false readings,
which could lead to possible electric
shock or personal injury, replace the
battery as soon as the battery indicator
appears.

3

Indicates negative reading.

4

Test of diode.

5

The continuity buzzer is on.

6

The relative value mode is on, which
display the present value minus the stored
value.

%

7

The relative percentage value mode is
on. It displays the percentage value of
the relative value and stored value.

DATA

HOLD

8

Data hold is active.

DC AC Indicator for DC/AC voltage or current.

The displayed value is the mean value.

9

Display the present chosen range.8000mV

10

Percent, used for duty cycle
measurements.

%

11

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V, mV

Display Symbols (2)

12

,

k , M

W: Ohm. The unit of resistance.
kW: kilohm. 1 x 103 or 1000 ohms.
MW: Megohm. 1 x 106 or 1,000,000

ohms.

Hz, kHz,

MHz

Hz: Hertz. The unit of frequency.
kHz: Kilohertz. 1 x 103 or 1000 hertz.
MHz: Meghertz. 1 x 106 or1,000,000

hertz.

V: Volts. The unit of voltage.
mV: Millivolt. 1 x 10-3 or 0.001 volts.

A: Amperes (amps). The unit of

current.

mA: Milliamp. 1 x 10-3 or 0.001

amperes.

F: Farad. The unit of capacitance.
mF: Microfarad. 1 x 10

-6

or 0.000001

farads.

nF: Nanofarad. 1 x 10-9 or

0.000000001 farads.

S: Siemens. The unit of

conductance.

nS: Nanosiemens. 1 x 10-9 or

0.000000001 siemens.

Maximum, minimum and average
recording mode enabled. Present reading
displayed.

13

100ms response time.
Maximum reading displayed.
Minimum reading displayed.
Average reading displayed.

14

Provides an analogue indication of the
present input, quick response.

15

Polarity indicator for the analogue bar
graph display, no display for positive.

The input value is too large for the selected
range.

16

Computer and the Meter is connected
properly. Data output is in progress.

17

A, mA

F , F, nF

nS

100ms

MAX

MIN

AVG

Analogue

Bar

Graph

RS232C

K :
M :

:

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Measurement Ranges (1)

A measurement range determines the highest value the
Meter can measure. Most Meter functions have more
than one range. See "Accuracy Specifications."

A. Selecting a Measurement Range

Being in the right measurement range is important:
l If the range is too low for the input, the Meter displays

to indicate an overload.

l If the range is too high, the Meter will not display

the most accurate measurement.

B. Manual Ranging and Autoranging

The Meter has both manual range and autorange options:
l In the autorange mode, the Meter selects the best

range for the input detected.
This allows you to switch test points without having
to reset the range.

l In the manual range mode, you select the range.

This allows you to override autorange and lock the
Meter in a specific range.

The Meter defaults to the autorange mode in
measurement functions that have more than one range.
When the Meter is in the autorange mode, is
displayed.

To enter and exit the manual range mode:

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1. Press RANGE.
The Meter enters the manual range mode and
turns off.
Each presses of RANGE increments the range.
When the highest range is reached, the Meter
wraps to the lowest range.

2. To exit the manual range mode, press and hold
RANGE for over one second.
The Meter returns to the autorange mode and
is displayed.

Note

l In Hold and MAX MIN mode, press RANGE exits

these measurement modes and enters manual
range mode.

l In Hz measurement mode, press RANGE to attenuate

10 times of input signal amplitude which can increase
the Meter sensitivity and stabilize the correct reading.

Measurement Ranges (2)

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