UNI-T UT805 Operating Manual

Model UT805

OPERATING MANUAL

TABLE OF CONTENTS
TITLE PAGE

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Model UT805: OPERATING MANUAL

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Overview
Unpacking Inspection
Safety Information
Rules For Safe Operation
International Electrical Symbols
The Meter Structure
A. Front Panel
B. Rear Panel
Functional Buttons
Display Symbols
Measurement Operation
A. DC Voltage Measurement
B. AC Voltage Measurement
C. DC or AC Current Measurement
D. Measuring Resistance
E. Testing Diodes
F. Testing for Continuity
G. Capacitance Measurement
H. Frequency Measurement
Selecting a Measurement Range (

, AUTO and Button)
The Use of Relative Value Mode
MAX MIN Mode
The Use of STO and RCL Button
Operation of Hold Mode
General Specifications
Accuracy Specifications
A. DC Voltage

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TITLE PAGE

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Model UT805: OPERATING MANUAL

B. AC Voltage
C. DC Current
D. AC Current
E. Resistance
F. Diode Test
G. Continuity Test
H. Capacitance
I. Frequency
Calibration Procedure
A. DC Voltage
B. AC Voltage
C. DC Current
D. AC Current
E. Resistance
F. AC Voltage with DC deviation (AC+DC)
G. AC Current with DC deviation (AC+DC)
Summary of error codes
Maintenance
A. General Service
B. Replacing the Fuses
RS232C and USB Serial Port
System Requirements for Installing the UT805 Interface Program
RS232C Serial Port
A. Connecting between the Meter and computer
B. RS232C Port Cable
C. Setting of RS232C Serial Ports
USB Serial Port
A. Connecting between the Meter and computer
B. Setting of USB Serial Ports

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Model UT805: OPERATING MANUAL

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 Safety Operation”
carefully before using the Meter.

Model UT805 is a kind of 5 1/2 digit, vacuum-fluorescent,
dual display bench-type true RMS Multimeter (hereafter
referred to as “the Meter”). The Meter’s circuit design
is the combination of large scale integrated simulation
and digital circuit, taking microcomputer technology
with 24 counts A/D converter as a core, highly precise
amplifier, True RMS’s AC converter and full electronic
calibration technique to make it as a reliable and accurate
Multimeter.

In addition to all the conventional features including
DC/AC voltage, current, resistance, diode, continuity
test, capacitance, frequency, there is a recall function.
RS232C and USB standard serial port for easy
connection with computer to realize macro recording
and monitoring and capture of transient dynamic data,
displaying change of waveform during the measurement,
providing data and evidence to engineering technicians
for scientific research.

This is also a highly applied digital multimeter of good
performance with full overload protection. This Meter
uses AC power to make it becoming a better electrical
equipment.

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Item Description Qty

Model UT805: OPERATING MANUAL

Unpacking Inspection

Carefully remove the Meter from its shipping container and 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.

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Operating Manual
Test Lead
Alligator Clip
Multi-Purpose Socket
Line Cord (AC220V~50Hz, 15W or AC110V~50Hz, 15W)
RS232C Interface Cable
USB Interface Cable
Installation Guide & Computer Interface Software (CD-ROM)

1 piece
1 pair
1 pair
1 piece
1 piece
1 piece
1 piece
1 piece

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Model UT805: OPERATING MANUAL

Safety Information

This Meter complies with the standards IEC61010: in
pollution degree 2, overvoltage category (CAT. I 1000V,
CAT II 600V) and double insulation.

CAT. III: Distribution level, fixed installation, with smaller
transient overvoltage than CAT. IV.
CAT IV: Primary supply level, overhead lines, cable
systems 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 7.

Rules For Safe Operation

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:

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.
Inspect the test leads and power cord for damaged
insulation or exposed metal. Check the test leads
for continuity. Replace damaged test leads and power
cord with identical model number or electrical
specifications before using the Meter.
Inspect the VFD display for no display..
Do not apply more than the rated voltage, as marked
on the Meter, between the terminals or between any
terminal and grounding.

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Model UT805: OPERATING MANUAL

Ensure the Meter is at right measurement position
range. Disconnect the connection between the test
lead and the circuit under tested before changing
over the range. No changeover of range shall be
made during measurement is conducted to prevent
damage of the Meter.
When the Meter working at an effective voltage over
60V in DC or 30V in AC, special care should be taken
for there is danger of electric shock.
Use the proper terminals, function, and range for your
measurements.
Under the manual ranging mode, if the value to be
measured is unknown, use the maximum
measurement position and reduce the range step by
step until a satisfactory reading is obtained.
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.
When using the test leads, keep your fingers behind
the finger guards.

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Disconnect circuit power and discharge all high­voltage capacitors before testing on-line resistance,
continuity, diodes, current, or capacitance.
Before measuring current, check the Meter’s fuses
and turn off power to the circuit before connecting
the Meter to the circuit.
Remove test leads, RS232C interface cable, USB
interface cable and alligator clip from the Meter and
turn the Meter power off before opening the Meter
case.
When servicing the Meter, use only the same model
number or identical electrical specifications
replacement parts.
The internal circuit of the Meter shall not be altered
at will to avoid damage of the Meter and any accident.
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.
The Meter is suitable for indoor use.
Turn the Meter power off when it is not in use.

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Model UT805: OPERATING MANUAL

International Electrical Symbols

AC or DC
Grounding
Double Insulated
Warning. Refer to the Operating Manual
High Voltage
Continuity Test
Diode
Capacitance Test
Fuse
Conforms to Standards of European Union

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Model UT805: OPERATING MANUAL

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789101112

The Meter Structure

A. Front Panel (see figure 1)

VFD Display
Primary Functional Buttons: Different key functions
selection.
COM Input Terminal: Negative input terminal,
inserting the black test lead.
V/ Input T erminal: Positive input terminal for voltage
and resistance measurement, inserting the red test
lead.
200mA MAX Input Terminal: Positive input terminal
for mA measurement, inserting the red test lead.

6. 10A MAX Input Terminal: Positive input terminal
for A measurement, inserting the red test lead.

Input Terminal: Positive input terminal for
capacitance, frequency, diode and continuity
measurement, inserting the red test lead.
2mA and 200mA Buttons: mA and A
measurement selection
AC+DC Button: The measurement of AC voltage
or current with DC deviation.

(figure 1)

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Model UT805: OPERATING MANUAL

CAL Button: Calibrate the accuracy of Voltage,

Current and Resistance
Secondary Functional Buttons: Different side
functions selection.
RANGE Button ( , AUTO and ): Select Auto or
Manual ranging

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4.

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6.

7.

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Model UT805: OPERATING MANUAL

1 2 3 4 5

678

B. Rear Panel (see figure 2)

HI Input Terminal:
4-wire configuration to measure resistance: high
current terminal, inserting red test lead.
LO Input Terminal
4-wire configuration to measure resistance: low
current terminal, inserting black test lead.
HI Input Terminal
4-wire configuration to measure resistance, high
current terminal, inserting red test lead.
LO Input Terminal
4-wire configuration to measure resistance, low
current terminal, inserting black test lead
Power: The on off switch of AC220V~50Hz, 15W or
AC110V~50Hz, 15W power supplier. “I” means
power up while “O” means power off.
Power-Line Cord Connector: Plug the AC220V
~50Hz,15W or AC110V~50Hz, 15W line cord
USB Interface Connector
RS232C Interface Connector

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(figure 2)

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Model UT805: OPERATING MANUAL

Functional Buttons

The pushbuttons on the front panel select the Meter functions and operations. Below table indicated for information
about the functional button operations.

Button

, AUTO and

Button)

Switching between auto and manual ranging, step through the ranges when the Meter is at manual
ranging measurement mode.
Continuity Test
Diode Test
Frequency Test
Capacitance Test
Resistance Measurement:

AC Voltage Measurement, displaying True RMS value
DC Voltage Measurement
AC Current Measurement, displaying True RMS value

Operation Performed

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Press to enter resistance measurement mode. Use the front input terminals for 2 wire
measurement and the back input terminals for 4 wire measurement.

ACV
DCV

ACI

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Model UT805: OPERATING MANUAL

Button

AC Current Measurement

It is used to measure AC Voltage or Current with DC deviation:

It is a calibration button:

Press REL to enter and exit REL mode.:
Press MAX MIN to select the maximum and minimum value.

Operation Performed

DCI

2mA &

200mA

AC+DC

CAL

REL

Press 2mA down to select 2mA current measurement range.
Press 200mA down to select 200mA current measurement range.
Press both 2mA and 200mA down is a mis-operation, the Meter displays “ --Err 1-“.
When both 2mA and 200mA are not pressed down, 10A range is default when measuring current.

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lt can only be used at AC Voltage or AC Current measurement mode otherwise the Meter displays
“--Err1-“, then back to the previous measurement range.

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Press it to calibrate ACV, DCV, ACI, DCI, ACV and DCV with DC deviation, and resistance.
Details refer to page 52 of this operating manual.

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Model UT805: OPERATING MANUAL

MAX MIN

STO and

RCL

HOLD

Button

Press MAX MIN to select the maximum and minimum value.

HOLD has two features:

1. Data Holding

2. Exit STO, RCL and MAX MIN mode.

Operation Performed

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Press STO to store the reading.
Press RCL to recall the stored reading.

Press HOLD to enter Hold mode, the VFD display
Press HOLD again to exit Hold mode, the disappear.

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Press HOLD to exit STO, RCL and MAX MIN mode when the Meter is at STO, RCL and MAX
MIN measurement mode.

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Model UT805: OPERATING MANUAL

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121314151617181920

STO
RCL

AUTO

HOLD

AC+DC TrueRMS MAX MIN AVG

S

mS

kHz

mVAnF

MK WHz

Display Symbols (see figure 3)

µ

µ

(figure 3)

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Model UT805: OPERATING MANUAL

Number Symbol Meaning

Indicator for high voltage
Data hold is active
Indicator for AC voltage or current
Indicator for AC AC Voltage or Current with DC deviation measurement
Indicator for True RMS value of AC measurement
Display of maximum value
Display of minimum value
Display of average value
Test of diode
Secondary Display
The unit of frequency in cycles/second:
µS: Microsecond
mS: Millisecond

AC

AC+DC

True RMS

MAX

MIN

AVG

Smaller digits

µS

mS

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HOLD

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Model UT805: OPERATING MANUAL

Number Symbol Meaning

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kHz

nF
µF

mF

mA

A

mV

V

k

M

The unit of frequency of AC measurement: Kilohertz (shown in the secondary display)
The unit of capacitance
nF : Nanofarad
µF : Microfarad
mF : Millifarad

A : Amperes (amps). The unit of current.
mA : Milliamp
V : Volts. The unit of voltage.
mV : Millivolt.

: Ohm. The unit of resistance.
k : kilohm.
M : Megaohm.

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Model UT805: OPERATING MANUAL

Number Symbol Meaning

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Relative mode is on
The continuity buzzer is on.
Primary Display
Indicates negative reading.
Reading storage is on
Reading recalling is on
Auto ranging mode indicator

Larger digits

STO
RCL

AUTO

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To measure DC voltage, connect the Meter as follows:

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Model UT805: OPERATING MANUAL

COM

RL

DCV

Measurement Operation

If you have not done so, plug the line cord into the
connector on the rear of the Meter.

A. DC Voltage Measurement (See figure 4)

Warning
To avoid harms to you or damages to the Meter from
electric shock, please do not attempt to measure
voltages higher than 1000V or 750V rms although
readings may be obtained.

Insert the red test lead into the V/ terminal and the
black test lead into the COM terminal.
Press the DCV button. Auto ranging is default, the
Meter will select the appropriate range, and an
annunciator on the display will indicate measurement
units. Or you could select the manual ranging mode
according to the “Selecting a Measurement Range
( , AUTO and Button)” section.

(figure 4)