Extech EX520 Operating Manual

User's Guide

True RMS Industrial Multimeter

Extech EX520

Introduction

Congratulations on your purchase of the Extech EX520 True RMS Autoranging Multimeter.
This meter measures AC/DC Voltage, AC/DC Current, Resistance, Capacitance, Frequency
(electrical & electronic), Diode Test, and Continuity plus Thermocouple Temperature. It
features a waterproof, rugged design for heavy duty use. Proper use and care of this meter
will provide many years of reliable service.

Safety

This symbol adjacent to another symbol, terminal or operating device
indicates that the operator must refer to an explanation in the Operating
Instructions to avoid personal injury or damage to the meter.

WARNING

CAUTION

MAX
1000V

PER IEC1010 OVERVOLTAGE INSTALLATION CATEGORY

OVERVOLTAGE CATEGORY I

Equipment of OVERVOLTAGE CATEGORY I is equipment for connection to circuits in
which measures are taken to limit the transient overvoltages to an appropriate low level.

Note – Examples include protected electronic circuits.

OVERVOLTAGE CATEGORY II

Equipment of OVERVOLTAGE CATEGORY II is energy-consuming equipment to be
supplied from the fixed installation.

Note – Examples include household, office, and laboratory appliances.

OVERVOLTAGE CATEGORY III

Equipment of OVERVOLTAGE CATEGORY III is equipment in fixed installations.
Note – Examples include switches in the fixed installation and some equipment for industrial
use with permanent connection to the fixed installation.

OVERVOLTAGE CATEGORY IV

Equipment of OVERVOLTAGE CATEGORY IV is for use at the origin of the installation.
Note – Examples include electricity meters and primary over-current protection equipment

This WARNING symbol indicates a potentially hazardous situation, which
if not avoided, could result in death or serious injury.

This CAUTION symbol indicates a potentially hazardous situation, which
if not avoided, may result damage to the product.

This symbol advises the user that the terminal(s) so marked must not be
connected to a circuit point at which the voltage with respect to earth
ground exceeds (in this case) 1000 VAC or VDC.

This symbol adjacent to one or more terminals identifies them as being
associated with ranges that may, in normal use, be subjected to
particularly hazardous voltages. For maximum safety, the meter and its
test leads should not be handled when these terminals are energized.

This symbol indicates that a device is protected throughout by double
insulation or reinforced insulation.

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SAFETY INSTRUCTIONS

This meter has been designed for safe use, but must be operated with caution. The rules
listed below must be carefully followed for safe operation.

1. NEVER apply voltage or current to the meter that exceeds the specified maximum:

Input Protection Limits

Function Maximum Input

V DC or V AC 1000VDC/AC rms

mA AC/DC 800mA 1000V fast acting fuse

A AC/DC

Frequency, Resistance, Capacitance,
Diode Test, Continuity

Temperature 1000VDC/AC rms

2. USE EXTREME CAUTION when working with high voltages.

3. DO NOT measure voltage if the voltage on the "COM" input jack exceeds 600V above

earth ground.

4. NEVER connect the meter leads across a voltage source while the function switch is in

the current, resistance, or diode mode. Doing so can damage the meter.

5. ALWAYS discharge filter capacitors in power supplies and disconnect the power when

making resistance or diode tests.

6. ALWAYS turn off the power and disconnect the test leads before opening the covers to

replace the fuse or batteries.

7. NEVER operate the meter unless the back cover and the battery and fuse covers are in

place and fastened securely.

8. If the equipment is used in a manner not specified by the manufacturer, the protection

provided by the equipment may be impaired.

10A 1000V fast acting fuse (20A for 30 seconds
max every 15 minutes)

1000VDC/AC rms

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Controls and Jacks

1. 6,000 count LCD display

2. RANGE button

3. Hz and % button

4. Mode button

5. Function switch

6. mA, µA and 10A input jacks

7. COM input jack

8. Positive input jack

9. HOLD and Backlight button

10. RELATIVE button

11. MAX/MIN button

Note: Tilt stand and battery compartment are

on rear of unit.

Symbols and Annunciators

Auto power off

•))) Continuity

Diode test

Battery status
n nano (10
µ micro (10
m milli (10
A Amps
k kilo (10
F Farads (capacitance)
M mega (10
Ω Ohms
Hz Hertz (frequency) V Volts
% Percent (duty ratio) REL Relative
AC Alternating current AUTO Autoranging
DC Direct current HOLD Display hold
ºF Degrees Fahrenheit ºC Degrees Centigrade
MAX Maximum MIN Minimum

-9

) (capacitance)

-6

) (amps, cap)

-3

) (volts, amps)

3

) (ohms)

6

) (ohms)

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Operating Instructions

WARNING: Risk of electrocution. High-voltage circuits, both AC and DC, are very
dangerous and should be measured with great care.

1. ALWAYS turn the function switch to the OFF position when the meter is not in use.

2. If “OL” appears in the display during a measurement, the value exceeds the range you
have selected. Change to a higher range.

DC VOLTAGE MEASUREMENTS

CAUTION: Do not measure DC voltages if a motor on the circuit is being switched ON or

OFF. Large voltage surges may occur that can damage the meter.

1. Set the function switch to the green VDC position.

2. Insert the black test lead banana plug into the negative COM
jack.
Insert the red test lead banana plug into the positive V jack.

3. Touch the black test probe tip to the negative side of the circuit.
Touch the red test probe tip to the positive side of the circuit.

4. Read the voltage in the display.

AC VOLTAGE (FREQUENCY, DUTY CYCLE) MEASUREMENTS

WARNING: Risk of Electrocution. The probe tips may not be long enough to contact the

live parts inside some 240V outlets for appliances because the contacts are recessed
deep in the outlets. As a result, the reading may show 0 volts when the outlet actually has
voltage on it. Make sure the probe tips are touching the metal contacts inside the outlet
before assuming that no voltage is present.

CAUTION: Do not measure AC voltages if a motor on the circuit is being switched ON or
OFF. Large voltage surges may occur that can damage the meter.

1. Set the function switch to the green VAC/Hz/% position.

2. Insert the black test lead banana plug into the negative COM
jack.
Insert red test lead banana plug into the positive V jack.

3. Touch the black test probe tip to the neutral side of the
circuit.
Touch the red test probe tip to the “hot” side of the circuit.

4. Read the voltage in the display.

5. Press the HZ/% button to indicate “Hz”.

6. Read the frequency in the display.

7. Press the Hz/% button again to indicate “%”.

8. Read the % of duty cycle in the display.

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DC CURRENT MEASUREMENTS

CAUTION: Do not make 20A current measurements for longer than 30 seconds.

Exceeding 30 seconds may cause damage to the meter and/or the test leads.

1. Insert the black test lead banana plug into the negative COM
jack.

2. For current measurements up to 6000µA DC, set the function
switch to the yellow µA position and insert the red test lead
banana plug into the µA/mA jack.

3. For current measurements up to 600mA DC, set the function
switch to the yellow mA position and insert the red test lead
banana plug into the µA/mA jack.

4. For current measurements up to 20A DC, set the function switch
to the yellow 10A/HZ/% position and insert the red test lead
banana plug into the 10A jack.

5. Press the MODE button to indicate “DC” on the display.

6. Remove power from the circuit under test, then open up the
circuit at the point where you wish to measure current.

7. Touch the black test probe tip to the negative side of the circuit.
Touch the red test probe tip to the positive side of the circuit.

8. Apply power to the circuit.

9. Read the current in the display.

AC CURRENT (FREQUENCY, DUTY CYCLE) MEASUREMENTS

CAUTION: Do not make 20A current measurements for longer than 30 seconds.

Exceeding 30 seconds may cause damage to the meter and/or the test leads.

1. Insert the black test lead banana plug into the negative COM

jack.

2. For current measurements up to 6000µA AC, set the function

switch to the yellow µA position and insert the red test lead
banana plug into the µA/mA jack.

3. For current measurements up to 600mA AC, set the function

switch to the yellow mA position and insert the red test lead
banana plug into the µA/mA jack.

4. For current measurements up to 20A AC, set the function

switch to the yellow 10A/HZ/% position and insert the red test
lead banana plug into the 10A jack.

5. Press the MODE button to indicate “AC” on the display.

6. Remove power from the circuit under test, then open up the

circuit at the point where you wish to measure current.

7. Touch the black test probe tip to the neutral side of the circuit.

Touch the red test probe tip to the “hot” side of the circuit.

8. Apply power to the circuit.

9. Read the current in the display.

10. Press the Hz/% button to indicate “Hz”.

11. Read the frequency in the display.

12. Press the Hz/% button again to indicate “%”.

13. Read the % duty cycle in the display.

14. Press the Hz/% button to return to current measurement.

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RESISTANCE MEASUREMENTS

WARNING: To avoid electric shock, disconnect power to the unit under test and

discharge all capacitors before taking any resistance measurements. Remove the
batteries and unplug the line cords.

1. Set the function switch to the green Ω CAP position.

2. Insert the black test lead banana plug into the negative COM
jack.
Insert the red test lead banana plug into the positive Ω jack.

3. Press the MODE button to indicate “Ω" on the display.

4. Touch the test probe tips across the circuit or part under test. It
is best to disconnect one side of the part under test so the rest
of the circuit will not interfere with the resistance reading.

5. Read the resistance in the display.

CONTINUITY CHECK

WARNING: To avoid electric shock, never measure continuity on circuits or wires that

have voltage on them.

1. Set the function switch to the green Ω CAP position.

2. Insert the black lead banana plug into the negative COM jack.
Insert the red test lead banana plug into the positive Ω jack.

3. Press the MODE button to indicate” "and “Ω” on the display

4. Touch the test probe tips to the circuit or wire you wish to check.

5. If the resistance is less than approximately 35Ω, the audible
signal will sound. If the circuit is open, the display will indicate
“OL”.

DIODE TEST

1. Set the function switch to the green Ω CAP position.

2. Insert the black test lead banana plug into the negative COM jack
and the red test lead banana plug into the positive V jack.

3. Press the MODE button to indicate and V on the display.

4. Touch the test probes to the diode under test. Forward voltage will
typically indicate 0.400 to 0.700V. Reverse voltage will indicate
“OL”. Shorted devices will indicate near 0V and an open device will
indicate “OL” in both polarities.

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EX520 V2.3 04/29/07

TEMPERATURE MEASUREMENTS

1. Set the function switch to the green Temp position.

2. Insert the Temperature Probe into the input jacks, making
sure to observe the correct polarity.

3. Press the MODE button to indicate ºF or ºC

4. Touch the Temperature Probe head to the part whose
temperature you wish to measure. Keep the probe touching
the part under test until the reading stabilizes (about 30
seconds).

5. Read the temperature in the display.

Note: The temperature probe is fitted with a type K mini connector.

A mini connector to banana connector adaptor is supplied
for connection to the input banana jacks.

CAPACITANCE MEASUREMENTS

WARNING: To avoid electric shock, disconnect power to the unit under test and

discharge all capacitors before taking any capacitance measurements. Remove the
batteries and unplug the line cords.

1. Set the rotary function switch to the green Ω CAP
position.

2. Insert the black test lead banana plug into the negative COM
jack.
Insert the red test lead banana plug into the positive V jack.

3. Press the MODE button to indicate “nF” on the display.

4. Touch the test leads to the capacitor to be tested.

5. The test may take up to 3 minutes or more for large capacitors
to charge. Wait until the readings settle before ending the test.

6. Read the capacitance value in the display

FREQUENCY/DUTY CYCLE MEASUREMENTS (ELECTRONIC)

1. Set the rotary function switch to the green “Hz %” position.

2. Press the Hz/% button to indicate “Hz” in the display.

3. Insert the black lead banana plug into the negative COM jack
and the red test lead banana plug into the positive Hz jack.

4. Touch the test probe tips to the circuit under test.

5. Read the frequency on the display.

6. Press the Hz/% button again to indicate “%” on the display.

7. Read the % of duty cycle on the display.

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EX520 V2.3 04/29/07

AUTORANGING/MANUAL RANGE SELECTION

When the meter is first turned on, it automatically goes into Autoranging. This automatically
selects the best range for the measurements being made and is generally the best mode
for most measurements. For measurement situations requiring that a range be manually
selected, perform the following:

1. Press the RANGE key. The “AUTO” display indicator will turn off.

2. Press the RANGE key to step through the available ranges until you select the range you
want.

3. To exit the Manual Ranging mode and return to Autoranging, press and hold the RANGE
key for 2 seconds.

Note: Manual ranging does not apply for the Capacitance and Frequency functions.

MAX/MIN

Note: When using the MAX/MIN function in Autoranging mode, the meter will “lock” into

the range that is displayed on the LCD when MAX/MIN is activated. If a MAX/Min
reading exceeds that range, an “OL” will be displayed. Select the desired range
BEFORE entering MAX/MIN mode.

1. Press the MAX/MIN key to activate the MAX/MIN recording mode. The display icon
"MAX" will appear. The meter will display and hold the maximum reading and will update
only when a new “max” occurs.

2. Press the MAX/MIN key again and the display icon "MIN" will appear. The meter will
display and hold the minimum reading and will update only when a new “min” occurs.

3. To exit MAX/MIN mode press and hold the MAX/MIN key for 2 seconds.

RELATIVE MODE

The relative measurement feature allows you to make measurements relative to a stored
reference value. A reference voltage, current, etc. can be stored and measurements made
in comparison to that value. The displayed value is the difference between the reference
value and the measured value.

1. Perform the measurement as described in the operating instructions.

2. Press the REL button to store the reading in the display and the "REL" indicator will
appear on the display.

3. The display will now indicate the difference between the stored value and the measured
value.

4. Press the REL button to exit the relative mode.

Note: The Relative function does not operate in the Frequency function.

DISPLAY BACKLIGHT

Press the HOLD key for >1 second to turn on or off the display backlight function. The
backlight will automatically turn off after 10 seconds.

HOLD

The hold function freezes the reading in the display. Press the HOLD key momentarily to
activate or to exit the HOLD function.

AUTO POWER OFF

The auto off feature will turn the meter off after 15 minutes. To disable the auto power off
feature, hold down the MODE button and turn the meter on.

LOW BATTERY INDICATION

The icon will appear in the lower left conner of the display when the battery voltage
becomes low. Replace the battery when this appears.

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EX520 V2.3 04/29/07

Maintenance

WARNING: To avoid electric shock, disconnect the test leads from any source of voltage
before removing the back cover or the battery or fuse covers.

WARNING: To avoid electric shock, do not operate your meter until the battery and fuse
covers are in place and fastened securely.

This MultiMeter is designed to provide years of dependable service, if the following care
instructions are performed:

1. KEEP THE METER DRY. If it gets wet, wipe it off.

2. USE AND STORE THE METER IN NORMAL TEMPERATURES. Temperature
extremes can shorten the life of the electronic parts and distort or melt plastic parts.

3. HANDLE THE METER GENTLY AND CAREFULLY. Dropping it can damage the
electronic parts or the case.

4. KEEP THE METER CLEAN. Wipe the case occasionally with a damp cloth. DO NOT
use chemicals, cleaning solvents, or detergents.

5. USE ONLY FRESH BATTERIES OF THE RECOMMENDED SIZE AND TYPE. Remove
old or weak batteries so they do not leak and damage the unit.

6. IF THE METER IS TO BE STORED FOR A LONG PERIOD OF TIME, the batteries
should be removed to prevent damage to the unit.

BATTERY INSTALLATION

WARNING: To avoid electric shock, disconnect the test leads from any source of voltage

before removing the battery cover.

1. Turn power off and disconnect the test leads from the meter.

2. Open the rear battery cover by removing two screws (B) using a Phillips head
screwdriver.

3. Insert the battery into battery holder, observing the correct polarity.

4. Put the battery cover back in place. Secure with the screws.

WARNING: To avoid electric shock, do not operate the meter until the battery cover is in
place and fastened securely.

NOTE: If your meter does not work properly, check the fuses and batteries to make sure that

they are still good and that they are properly inserted.

A

A

B

B

A

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F1 F2

EX520 V2.3 04/29/07

REPLACING THE FUSES

WARNING: To avoid electric shock, disconnect the test leads from any source of voltage

before removing the fuse cover.

1. Disconnect the test leads from the meter.

2. Remove the protective rubber holster.

3. Remove the battery cover (two “B” screws) and the battery.

4. Remove the six “A” screws securing the rear cover.

5. Gently remove the old fuse and install the new fuse into the holder.

6. Always use a fuse of the proper size and value (0.8A/1000V fast blow for the 600mA
range [SIBA 70-172-40], 10A/1000V fast blow for the 20A range [SIBA 50-199-06]).

7. Replace and secure the rear cover, battery and battery cover.

WARNING: To avoid electric shock, do not operate your meter until the fuse cover is in
place and fastened securely.

Warranty

EXTECH INSTRUMENTS CORPORATION warrants the basic instrument to be free of
defects in parts and workmanship for three years from date of shipment (a six month limited
warranty applies on sensors and cables). If it should become necessary to return the
instrument for service during or beyond the warranty period, contact the Customer Service
Department at [phone] EXTENSION 210 for authorization or visit www.extech.com
more information. A Return Authorization (RA) number must be issued before any
product is returned to Extech. The sender is responsible for shipping charges, freight,
insurance and proper packaging to prevent damage in transit. This warranty does not apply to
defects resulting from action of the user such as misuse, improper wiring, operation outside of
specification, improper maintenance or repair, or unauthorized modification. Extech
specifically disclaims any implied warranties or merchantability or fitness for a specific
purpose and will not be liable for any direct, indirect, incidental or consequential damages.
Extech's total liability is limited to repair or replacement of the product. The warranty set forth
above is inclusive and no other warranty, whether written or oral, is expressed or implied.

for

Calibration and Repair Services

Extech offers repair and calibration services for the products we sell. Extech also provides
NIST certification for most products. Call the Customer Service Department for information on
calibration services available for this product. Extech recommends that annual calibrations be
performed to verify meter performance and accuracy.



Support line [phone]

Technical support: Extension 200; E-mail: [e-mail]

Repair & Returns: Extension 210; E-mail: [e-mail]

Product specifications subject to change without notice

For the latest version of this User’s Guide, Software updates, and other

up-to-the-minute product information, visit our website: www.extech.com

Extech Instruments Corporation, 285 Bear Hill Rd., Waltham, MA 02451

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EX520 V2.3 04/29/07

Specifications

Function Range Resolution Accuracy

DC Voltage

AC Voltage

All AC voltage ranges are specified from 5% of range to 100% of range

DC Current

AC Current

All AC voltage ranges are specified from 5% of range to 100% of range

NOTE: Accuracy is stated at 65oF to 83oF (18oC to 28oC) and less than 75% RH.

600mV 0.1mV

6V 0.001V

60V 0.01V

600V 0.1V

1000V 1V

50 to 60Hz 40Hz to 1KHz

6V 0.001V

60V 0.01V

600V 0.1V

1000V 1V

600µA 0.1µA

6000µA 1µA

60mA 0.01mA

600mA 0.1mA

6A 0.001A

10A 0.01A

(20A: 30 sec max with reduced accuracy)

40Hz to 1kHz

600µA 0.1µA

6000µA 1µA

60mA 0.01mA

600mA 0.1mA

6A 0.001A
10A 0.01A

(20A: 30 sec max with reduced accuracy)

±(1.0% reading + 3 dgts) ±(2.0% reading + 3 dgts)

±(0.09% reading + 2 digits)

±(1.0% reading + 3 digits)

±(1.5% reading + 3 digits)

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EX520 V2.3 04/29/07

Function Range Resolution Accuracy

Resistance

600Ω 0.1Ω

6kΩ 0.001kΩ

60kΩ 0.01kΩ

±(0.3% reading + 4 digits)

600kΩ 0.1kΩ

6MΩ 0.001MΩ

60MΩ 0.01MΩ ±(0.3% reading + 20 digits)

Capacitance

60nF 0.01nF

600nF 0.1nF

6µF 0.001µF

±(3.5% reading + 4 digits)

60µF 0.01µF

600µF 0.1µF

1000µF 1µF ±(5% reading + 5 digits)

Frequency
(electronic)

9.999Hz 0.001Hz

99.99Hz 0.01Hz

999.9Hz 0.1Hz

9.999kHz 0.001kHz

99.99kHz 0.01kHz

±(0.1% reading + 1 digits)

999.9kHz 0.1kHz

9.999MHz 0.001MHz

40MHz .01MHz

Sensitivity: 0.8V rms min. @ 20% to 80% duty cycle and <100kHz; 5Vrms min @

Frequency
(electrical)

Duty Cycle

20% to 80% duty cycle and > 100kHz

10.00-400Hz 0.01Hz

Sensitivity: 15Vrms

0.1 to 99.9% 0.1%

.

±(0.5% reading)

±(1.2% reading + 2 digits)

Pulse width: 100µs - 100ms, Frequency: 5Hz to 150kHz

Temp
(type-K)

-50 to 1382°F 1°F

-45 to 750°C 1°C

±(3.0% reading + 5°C /9°F digits)

(probe accuracy not included)

Note: Accuracy specifications consist of two elements:

• (% reading) – This is the accuracy of the measurement circuit.

• (+ digits) – This is the accuracy of the analog to digital converter.

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EX520 V2.3 04/29/07

Enclosure Double molded, waterproof (IP67)
Shock (Drop Test) 6.5 feet (2 meters)
Diode Test Test current of 0.9mA maximum, open circuit voltage 2.8V DC

typical

Continuity Check Audible signal will sound if the resistance is less than 100Ω

(approx.), test current <0.35mA

Temperature Sensor Requires type K thermocouple
Input Impedance >10MΩ VDC & >10MΩ VAC
AC Response True rms
ACV Bandwidth 40Hz to 1000Hz
Crest Factor ≤3 at full scale up to 500V, decreasing linearly to ≤1.5 at 1000V
Display 6,000 count backlit liquid crystal with bargraph
Overrange indication “OL” is displayed
Auto Power Off 15 minutes (approximately) with disable feature
Polarity Automatic (no indication for positive); Minus (-) sign for negative
Measurement Rate 2 times per second, nominal
Low Battery Indication “ ” is displayed if battery voltage drops below operating voltage
Battery One 9 volt (NEDA 1604) battery
Fuses mA, µA ranges; 0.8A/1000V ceramic fast blow

A range; 10A/1000V ceramic fast blow

Operating Temperature 41°F to 104°F (5°C to 40°C)
Storage Temperature -4°F to 140°F (-20°C to 60°C)
Operating Humidity Max 80% up to 87°F (31°C) decreasing linearly to 50% at 104°F

(40°C)

Storage Humidity <80%
Operating Altitude 7000ft. (2000meters) maximum.
Weight 0.753lb (342g) (includes holster).
Size 7.36” x 3.2” x 2.0” (187 x 81 x 50mm) (includes holster)
Safety This meter is intended for origin of installation use and protected,

against the users, by double insulation per EN61010-1 and
IEC61010-1 2
III 1000V; Pollution Degree 2. The meter also meets UL 61010-1,

nd

Edition (2004), CAN/CSA C22.2 No. 61010-1 2nd Edition (2004),

2
and UL 61010B-2-031, 1

nd

Edition (2001) to Category IV 600V and Category

st

Edition (2003)

Approvals UL CE
UL Listed The UL mark does not indicate that this product has been

evaluated for the accuracy of its readings.

Copyright © 2007 Extech Instruments Corporation.

All rights reserved including the right of reproduction

in whole or in part in any form.

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