Yokogawa MY40-01 Operating Manual

User’s

A

B

Protection cover fixing holes

Shoulder strap

Shoulder strap guide

Protection cover

WARNING

• Remove the probes from the tester and then turn off
the MEAS key before opening the casing to replace the batteries.

• Do not touch the MEAS key during replacement. Otherwise,
a high voltage may be produced.

CAUTION

•

Do not mix batteries of different types or new batteries with used ones.

• Always remove the batteries if the tester will not be used for
a prolonged period of time. If you store the tester with the batteries
left installed, fluid is likely to leak from them, resulting in
a malfunctioning of the instrument.

Note

The data above is typical. Nevertheless, the battery life varies
depending on the operating conditions. Check the batteries before
measurement.

OPEN

Clr

Enter

Select

250V

1000V

500V

2000MΩ

200MΩ

OFF

600V MAX

V

125V

MEM

LIGHT

COMP

ALARM

INSULATION

TESTER

1000V RELEASE

MEAS

PULL

LOCK

6. ALARM LED

7. Function selector switch

3. LIGHT key

2. MEAS key

5. COMPARATOR key

8. 1000-V RELEASE button
for setting 1000-V rating

4. Protective cover fitting

1. Display window
(LCD)

Front view

Rear view

Side view

9. Battery cover setscrew

10. Battery cover

11. Shoulder strap
guide

12. Earth terminal

13. Line terminal

1

2

3

4

Measurement category

CAT.1

CAT.2

CAT.3

CAT.4

Remarks

Appliances, portable equipments, etc.

Distribution board, circuit breaker, etc.

Overhead wire, cable systems, etc.

Description
For measurements performed on circuits

not directly connected to MAINS.
For measurements performed on circuits

directly connected to the low voltage installation.
For measurements performed

in the building installation.
For measurements performed

at the source of the low-voltage installation.

Manual

Thank you for purchasing the Yokogawa MY40 Insulation Tester.
To optimize all the functions of the instrument, please read this manual thoroughly before operating it.

Model MY40
Insulation Resistance T ester

Store this manual in a safe place for future reference.

Yokogawa Meters & Instruments Corporation
International Sales Dept.

Tachihi Bld. No.2, 6-1-3, Sakaecho, Tachikawa-shi,Tokyo 190-8586 Japan
Phone: [phone], Facsimile: 81-42-534-1426

YOKOGAWA CORPORATION OF AMERICA (U.S.A.)

Phone: [phone] Facsimile: 1-770-254-0928

YOKOGAWA EUROPE B. V. (THE NETHERLANDS)

Phone: [phone] Facsimile: 31-33-464-1610

YOKOGAWA AMERICA DO SUL LTDA. (BRAZIL)

Phone: [phone] Facsimile: 55-11-5681-4434

YOKOGAWA ENGINEERING ASIA PTE. LTD. (SINGAPORE)

Phone: [phone] Facsimile: 65-6241-2606

YOKOGAWA MEASURING INSTRUMENTS KOREA CORPORATION (KOREA)

Phone: [phone] to -0664 Facsimile: 82-2-551-0665

YOKOGAWA AUSTRALIA PTY. LTD. (AUSTRALIA)

Phone: [phone] Facsimile: 61-2-8870-1111

YOKOGAWA INDIA LTD. (INDIA)

Phone: [phone] Facsimile: 91-80-2852-1441

YOKOGAWA SHANGHAI TRADING CO., LTD. (CHINA)

Phone: [phone] Facsimile: 86-21-6880-4987

YOKOGAWA MIDDLE EAST B. S. C (C) (BAHRAIN)

Phone: [phone] Facsimile: 973-17-336100

YOKOGAWA ELECTRIC CIS LTD. (RUSSIAN FEDERATION)

Phone: [phone] Facsimile: 7-495-737-7869

■ About This Manual

• The contents of this manual are subject to change without prior
notice.

• Every effort has been made to ensure accuracy in the
preparation of this manual. Should any errors or omissions come
to your attention however, please inform Yokogawa Meters &
Instruments Corporation accordingly.

• Under absolutely no circumstances may the contents of this
manual be transcribed or copied, in part or in whole, without
obtaining permission.

IM3E-2008.8

1st Edition : Nov. 2000(YG)
All Rights Reserved, Copyright ©2000, Yokogawa M&C Corporation

1. Safety Precautions

Always observe the following instructions. Failure to do so may result
in electrical shock or other dangers that may lead to serious injury or
the loss of life.
Yokogawa is in no way liable for any damage resulting from the user's
mishandling of the tester.
For safe use of this tester , the f ollo wing saf ety symbols are used in the
user's manual:

WARNING

Indicates a hazard that may result in the loss of life or serious injury of
the user unless the described instruction is abided by.

CAUTION

Indicates a hazard that may result in an injury to the user and/or physi­cal damage to the product or other equipment unless the described
instruction is abided by.

Note

This provides important information for handling the tester and clari­fies tester functions.

The following symbols are used on the MY40 tester.

Danger! Handle with Care.

This symbol indicates that the operator must refer to an e xplanation in
the user's manual in order to avoid risk of injury or death of personnel
or damage to the tester.

High-voltage Terminal

This symbol indicates a dangerous voltage level (terminals with volt­ages exceeding 1000 volts must be so marked). Ne ver touch the termi­nals.

AC Voltage

This symbol indicates the presence of an AC voltage.

Double Insulation

This symbol indicates double insulation.

A2

IM MY40-E

6th Edition: Aug. 2008 (KP)

WARNING

■ Always observe the following instructions. Failure to do so may
result in electric shock or other dangers that may lead to serious
injury or the loss of life.

1. During Measurement of Insulation Resistance

•

A high voltage is present at the probes. Do not touch the measured

object or the earth or line terminal.

2. Immediately After Measurement of Insulation Resistance

• The probes or the measured object may remain highly charged.
Do not touch them immediately after the completion of measurement.

3. During Measurement of AC Voltages

• Do not press the MEAS key while measuring AC voltages.

•

Voltage that exceeds the specified limit must not be applied to terminals.

4. Probes

• Use the probes supplied by Yokogawa with this tester.

• Do not use probes that have deteriorated or are defective.

• Remove the probes from the measured object before attaching/

detaching the probes to/from the tester.

5. Insulation of Casing

• A puncture in the protective insulation may occur if there are any

cracks or other damage in the casing as a result of the instrument
having been dropped or knocked against another object.
Do not use the instrument before taking the necessary remedial
measures; ask the manufacturer to repair it.

6. The Measured Object

• Turn off the power to the measured object before you begin

measuring insulation resistance.

• Avoid touching any electrified parts while using the tester in

a location with live electricity. For safety, it is recommended that
you use a pair of rubber gloves or other alternative means.

7. Operating Environment

• Do not operate the tester in an atmosphere where any flammable

or explosive gas is present.

• Do not use the tester if there is condensation on it.

8. Disassembly

• No person, except personnel from Yokogawa is authorized to

disassemble this instrument.

■ Measurement Categories

Entrance
Cable

CAT.4

Internal Wiring

Distribution
Board

CAT.1

Fixed Equipment,
etc.

CAT.3

T

Equipment

2. Components

CAT.2

Outlet

3. Measuring Functions and Additional Features

■ Measuring Functions

• Measuring the insulation resistance (four ratings)
125 V/ 200 MΩ
250 V/ 200 MΩ
500 V/ 2000 MΩ
1000 V/ 2000 MΩ

• Measuring AC voltages (sine wave at 45 to 400 Hz)

• Measuring conductor resistances (0 to 400.0 Ω)
Continuity test (beeps for 40 Ω or less)

■ Additional Features

• Memory feature (data saving)
Up to 20 measured values of the insulation resistance for each
rating can be saved to memory.

• Live-line alarm
When an AC voltage of 40 V or more is applied between the
input terminals, the ALARM LED flashes and the buzzer beeps
(except during AC voltage measurement).

• Comparator
When a measured insulation resistance is less than the refer­ence value setting, the LOW mark appears and the buzzer
beeps.

• HOLD feature
Measured insulation resistances are automatically held for
approximately five seconds.

• High-voltage indication
If a DC voltage exists between the terminals, the HV mark
and the ALARM LED come on.

• Discharge feature
The tester is designed to begin discharging when the MEAS
key is turned off.
It indicates the discharging status with a bar graph, and the
HV mark and ALARM LED come on during discharging (and
off when discharging is complete).

•Auto-power off
The tester is automatically turned off when no key operations
are performed for 10 minutes.

• LCD backlight
The backlight can be turned on/off with the LIGHT key.

• Locking the MEAS key
Pulling the MEAS key up allows f or continuous measurement
over a prolonged time.

• Lock for inadvertent setting of 1000-V range
This mechanism protects the measured circuit from damage
due to inadvertent measurement with the highest voltage
(1000 V).

Ontline of Measurement Principle

A/D converter
and insulation

High voltage
generator
circuit





resistance
calculation
circuit

Discharge feature

Function (range)
selector switch

LCD

MEAS key

Four AA-size batteries

Block Diagram of Insulation Resistance Measurement Circuit

4. Overrange Display Functions

■ OL Display

The tester displays the OL mark when the measured resistance
exceeds the following values.

Insulation resistance measurement:
For 1000 V and 500 V ratings: 2000 MΩ
For 250 V and 125 V ratings: 200 MΩ

Conductor resistance measurement: 400 Ω

■

∞Display

The tester displays the
exceeds the following values.

Insulation resistance measurement:
For 1000 V and 500 V ratings: approx. 4000 MΩ
For 250 V and 125 V ratings: approx. 400 MΩ

■ Change to Upper/Lower Ranges

•To upper range
When the digital reading exceeds 4000, the measuring range
changes to the next upper range.

•To lower range
When the digital reading falls below 360, the measuring range
changes to the next lower range .

■ Lower Resolution Display

If the digits below the decimal point are not stable, they can be
automatically omitted to limit the resolution.

mark when the inter nal calculation

∞

LINE

EARTH

6. Functions for Each Component

1. Display window (LCD)

Displays the measured values and the function marks (see section
5, “Display Functions”).

2. MEAS key

Used for measuring the insulation resistance only.

3. LIGHT key: Used for turning on/off the backlight.
(MEM key): Also used for setting memory.

(Enter key): Also used for confirmation for the comparator and

memory functions.

4. Protective cover fitting

5. COMP key: Used for setting the comparator.

(Select key): Also used for selection for the comparator and

memory functions.

6. ALARM LED

Flashes for the live-line alarm, and is lit as a warning for the high

-voltage alarm.

7. Function switch

A rotary switch for setting measurement ratings with the following
positions:

•1000 V/ 2000 MΩ: Insulation resistance measurement

•500 V/ 2000 MΩ: Insulation resistance measurement

•250 V/ 200 MΩ: Insulation resistance measurement

•125 V/ 200 MΩ: Insulation resistance measurement

•AC voltage measurement (maximum input voltage: 600 V)

•Power off

•Conductor resistance measurement
Continuity test
CLr: Memory clear

8. 1000-V RELEASE button

Turn the function switch to the 1000 V rating position while press­ing this button.

9. Battery cover setscrew

Undo to replace batteries.

10. Battery cover

11. Shoulder strap guide

The shoulder strap is passed through it.

12. Earth terminal

Connection for earth probe.

13. Line terminal

Connection for line probe.

Note

• GUARD function is not a standard function.

7.

Using Protection Cover and Shoulder Strap

The tester comes with a protection cover and shoulder strap as
standard accessories.

• The protection cover can be used as a front cover
(for the display window) or as a bottom cover.
(It is set as the front cover when
delivered from the factory.)

• Using the shoulder strap allows you to position the
tester in front of your chest for ease of reading. Pass
the strap through the shoulder strap guide and ad­just the length of the strap to allow you a good view
of the tester.

• Remove the cover from the front, and attach it to
the bottom using the fixing hole (B) on the surface
of the cover. This is useful when the diaplay is too
close to your body to see clearly (See the figure
on the right).

•A belt on the cover which is fitted with pieces of
Velcro, can be used to store the probes (Remove
the probes from the tester terminals when storing
them).

5. Display Functions

Lit when the measured insulation resistance is being held.
Flashes when the battery voltage is low.
Lit when the rating setting is 1000 V/2000 MΩ.
Lit when the rating setting is 500 V/2000 MΩ.
Lit when the rating setting is 250 V/200 MΩ.

OL

Lit when the rating setting is 125 V/200 MΩ.
Indicates overrange.

Indicates the extension bar graph.
The extension bar graph shows ho w the measured v alue is

changing (trend) as follows:
Note that the number of

change.

marks means the degree of

Lit when:

• Pressing the MEAS key in insulation resistance measure-

• Residual electrical charges are present during discharg-

Lit when the comparator is activated.
Lit when the measured insulation resistance is lower than

the comparator setting value.
Lit when the memory feature is in use.

Indicates the unit for AC voltage measurement.
Indicates the unit for insulation resistances.
Indicates the unit for conductor resistance measurement.

Indicates the continuity mark, which is lit when the
measured insulation resistance is lower than 40 Ω.

Sub-display

Indicates:

• Comparator setting value or the storage number; or

• The storage number for memory.
Indicates the unit for insulation resistance for comparator.

: Change toward smaller values

: Change toward larger values

: Stable

ment; and
ing.

8. Before Measurement

1. Safety

• Read the handling precautions in this manual carefully.

• Make sure it is safe before starting measurement.

2. Battery Volta ge Verification

• Make sure that the battery voltages are within the valid rat­ings (i.e. the

• If the batteries are low, replace them as specified in the bat­tery replacement section of this manual.

Note

As the mark indication depends on the load (current
consumption), check that the mark does not appear for the
largest load when short-circuiting the earth probe and the line probe
(0 MΩ).

3. Connecting the Probes

• Plug the earth probe into the earth terminal.

• Plug the line probe into the line terminal.

WARNING

• Remove the probes from the measured object before attaching/
detaching the probes to/from the tester.

• Make sure the MEAS key is off when attaching/detaching
the probes to/from the tester.

4. Function Switch Verification

Be sure to confirm that the function switch is set to the desired rat-

ing.

5. 1000-V Rating

When measuring with the 1000-V rating, see section 12, “Double-

action 1000-V Function”.

mark is not flashing).

9. Battery Replacement

1. Loosen the battery cover setscrew, and then slide the cover off of
the main unit.

2. Replace all of the 4 batteries at the same time and make sure the
polarities of the new batteries are exactly as shown on the
battery holder.

3. After replacing the batteries, attach the battery cover and tighten the
setscrew.

10. Battery Life (Reference only)

For MY40 at rated 500 V/2000 MΩ:
Approximately 15 hours when in continuous operation with center v alue
indicated (approx. 50 MΩ; with standard supplied batteries).

11. Measuring the Insulation Resistance

Note

If the data being held is invalid, “----” is displayed and it cannot be
saved. In this case, perform measurement again and save the
data.

LIGHT

Note

To stop deleting of data:
Do not perform any key operation and wait for 10 seconds while
the “CLr” indication mentioned in step (3) is flashing; or
Turn the function switch to another rating.

Position of decimal point

Main display

Sub-display

Main display

Sub-display

Insulation resistance
measurement
(with comparator)

Measured value

Reference value

Comparator setting

Reference value

no.

Note

• To cancel the preset setting
Pressing the key (Select) in step (8) returns the setting
procedure to step (1). To stop the setting, turn the function switch
to the off position.

• To set the preset values for another rating
Turn the function dial to the desired rating (insulation resistance)
in step (8).

COMP

Name Model No. Quantity

Protection cover 93013 1

Shoulder strap 99005 1
Line probe 98001 1
Earth probe 98002 1
Batteries — 4

User,s manual IM MY40-E 1

Name

2. Hard case

58 mm, general-purpose

Description

Model No.

1. Spare probe tip for the
line probe (Model 98001)

99011

105 mm, breaker pin

93015

Houses both the main unit, the line
probe and the earth probe.

3. Accessory bag

B9108XA

Soft case, approx. 100 (W)  190 (H)
 40 (D) mm

4.

Replaceable-type line probe

98052

Cable length: 1000 mm

5. Spare probe tips for the
line probe (Model 98005)

6.

7.

8.

9.

B9600GN

B9635JK

B9600NZ

B9600NX

B9600NW

108 mm, sharp-pointed
338 mm, pickax-shaped

360 mm, hook-shaped
360 mm, for extension purposes

125(4.92)

103(4.06)

52.5(2.07)

1200(47.24)

1200(47.24)

Clr

Enter

Select

250V

1000V

500V

2000MΩ

200MΩ

OFF

600V MAX

V

125V

MEM

LIGHT

COMP

ALARM

INSULATION

TESTER

1000V RELEASE

MEAS

PULL

LOCK

Main unit

Earth probe

98002

Line probe

98001

1. Before Connecting the Probes

WARNING

• Turn off the power to the measured object before connecting or
measuring insulation resistance.

• Electrical charges may be present in the cables attached to or
metal of the electrical equipment being tested. Verify that the
equipment is free from electrical charges before connecting the
testing terminals.

• Be sure to confirm that the function switch is set to the desired
rating.

Insulation Resistance Measurement

Power supply side (primary)

Set the switch to OFF.

Earth probe

Line probe

Measurement wiring

Insulation resistance ratings:
125 V/ 200 MΩ
250 V/ 200 MΩ
500 V/ 2000 MΩ
1000 V/ 2000 MΩ

2. Setting the Function Switch

Turn the function switch to the desired measurement rating posi­tion. The initial display is “---- MΩ”.

3. Connecting the Earth Probe

• If the measured object is grounded, connect the earth probe
clip to the measured object’s ground line.

• If the measured object is not grounded, this process may be
omitted.

4. Connecting the Line Probe

•Bring the line probe into contact with the measured object,
and then press the MEAS key. The display indicates the in­sulation resistance of the measured object.

ON

OFF

Load side (secondary)

Note

During measurement, exercise care to prevent the leadwire of
the line probe from coming into contact with the ground, floor or
any other object. Not observing this precaution may result in
a failure to measure the correct insulation resistance.

5. After Measurement

WARNING

• Immediately after measurement, electrical charges resulting from
the applied testing voltage may remain present in the probes or
measured object.

• The tester, therefore, is designed to automatically begin
discharging electricity upon completion of measurement. Verify
that the ALARM LED turns off when discharging is complete.

12. Double-action 1000-V Function

The tester is equipped with the RELEASE button to protect the mea­sured circuit from damage due to inadvertent measurement at 1000 V.
To select the 1000 V rating, turn the function switch to the position while
pressing this button. To cancel the 1000 V rating, turn the function switch
to the off position or another rating position.

13. Live-line Alarm

Always turn off the power to the measured object before connecting or
measuring insulation resistance. If an AC voltage of more than 40 V is
applied, the ALARM LED flashes and the buzzer beeps. In this case,
stop the measurement immediately and check the power supply volt­age.

14. Locking the MEAS Key (for Continuous Measurement)

The MEAS key, when pulled up to the right, can be locked to ensure the
key remains turned on. Use this mechanism when making continuous
measurement over a prolonged period. Note, however, that leaving the
key turned on for an unreasonably long time will accelerate the dis­charge of the batteries.

19. LIGHT and COMP Keys

COMP

The

key is used as the Select key for settings and storage num-

bers of the comparator and memory functions.

LIGHT

The

key is used as the Enter key for settings and storage num-

bers of the comparator and memory functions. Pressing the Enter k e y
while the display is flashing, confirms selection of the setting or the
storage numbers.

•When setting the memory or comparator function
Turn the function switch to an insulation resistance rating position
while pressing and holding the

LIGHT

key or the

COMP

key until all the
displayed digits stop flashing and remain on, and the buzz er sounds .
Or position the function switch to a r ating of the insulation resistance
first, press the

LIGHT

key or the

COMP

key when all the digits appear , and

hold the key until the buzzer sounds.

■ Backlight

• The backlight remains off while the comparator is set.

• The backlight is lit when memory is in use.

20. Memory Feature (Data Saving)

Up to 20 measured values of the insulation resistance for each rating
can be saved to memory.

■ Displaying data

(1)Turn the function switch from power-off to a measurement rating

while pressing and holding the
“MEM” appears and “no .01” (stor age number) flashes on the sub-

display.

(2)Select a storage number.

Press the

COMP

key (Select) to select a storage number (no.01 to

no.20).
If an insulation resistance data is saved with the selected (displa yed)
number, the insulation resistance value is displayed.
If any data is not saved with the selected (displa yed) number , “----” is
displayed.

LIGHT

key (MEM).

■ Saving data

First select a storage number as in steps (1) and (2) above. Over­writing data is possible.
(3)Perform measurement with the MEAS key .
(4) Turn off the MEAS key. The measured value is held and starts

flashing. Press the

LIGHT

key (Enter) while the measured value is
flashing to save it to memory (it is held for five seconds in which
time the next data cannot be saved).

■ Deleting data

Data saved can be collectively deleted.
(1)Turn the function switch from power-off to the continuity test po-

sition (Clr) while pressing and holding the

key (MEM).

(2)“MEM” and “CLr” appear.

LIGHT

(3)Press the
(4)Press the

key (MEM). “CLr” starts flashing.

LIGHT

key (MEM) again while “CLr” is flashing. The b uzzer

sounds and all data are deleted (do not change the position of
the function dial for two seconds when “CLr” is displayed). The
tester changes its mode to measurement of conductor resis­tances.

■ Turning off the memory feature

Turn the function switch to the off position.

15. HOLD Feature

Measured insulation resistances are automatically held for approxi­mately five seconds. Turning off the MEAS key initiates holding.

• Turn off the power to the measured object before connecting or
measuring conductor resistance.

16. Measuring AC Voltages

1. Setting the Function Switch

WARNING

•

Do not press the MEAS key while measuring AC voltages.

• Voltage that exceeds the specified limit (600 V) must not be
applied to terminals. Doing so causes all digits of the measured
voltage to flash and the buzzer to beep.

1. Setting the Function Switch

Turn the function switch to an AC voltage
measurement (앑V) position.

2. Connecting the Earth Probe

• If the measured object is grounded,
connect the earth probe clip to the mea­sured object’s ground line.

• If the measured object is not grounded,
this process may be omitted.

3. Connecting the Line Probe

•Bring the line probe into contact with the measured object.
The display indicates the AC voltage of measured object.

17. Measuring Conductor Resistance (Continuity)

The tester can measure the conductor resistance of 0-400 Ω. The
buzzer beeps for resistances approximately 40 Ω or lower.

Turn the function switch to a conductor resistance measurement
( ) position.

2. Connecting the Earth Probe

Securely connect the earth probe to the measured object.

3. Connecting the Line Probe

Bring the line probe into contact with the measured object. The dis­play indicates the resistance of the measured object.

Note

You do not have to press the MEAS key when you measure
conductor resistances.

18. Auto Power-off

The tester is automatically turned off when no key operations are per­formed for 10 minutes.
The buzzer sounds 9 and a half minutes after the last key operation (at
1-sec intervals). If any measurement or k ey oper ation is not made while
the buzzer sounds, the tester is turned off. However, it is not turned off
when measurement is in progress or an alarm occurs.

To use the tester after the auto power-off is triggered, press the
or the
proceeding with the desired operation.

WARNING

COMP

key, or turn the function switch to the off position once before

LIGHT

key

21. Comparator

When a measured insulation resistance is less than the reference value
setting, the LOW mark appears and the buzzer sounds. Also the mea­sured value is automatically held for 5 seconds.

■ Selecting the reference value

Select from three preset values for each rating.
Default values:
no.01: 0.1 MΩ/ no.02: 0.2 MΩ/ no.03: 0.4 MΩ

(1) Turn the function switch to a measurement rating.
(2) Press the

(3)

display.

(4) Pressing the

play as follows.

0.1 MΩ / 0.2 MΩ / 0.4 MΩ / Comparator off (no display)
The reference value currently displa yed is selected as the compara­tor setting.

■ Setting the preset values

Each of the default preset values no.01 to no.03 can be changed
independently.

(1) Turn the function switch from power-off to a desired rating while

pressing and holding the
flashes. Press the

(2) Confirm the setting no. with the

The reference value on the main display can be set.

(3) Select the position of the decimal point with the
(4) Confirm the decimal point with the

(5) Select the number for each digit sequentially.

Pressing the
0 → 1 → 2 ··· 8 → 9 → 0

COMP

key.

appears and the reference value appears on the sub-

COMP

key (Select) changes the reference value dis-

COMP

COMP

key (Select) to select no.02 or no.03.

COMP

key (Select) changes the number as follows.

key. “no.01” on the sub-display

LIGHT

key (Enter).

COMP

key (Select).

LIGHT

key (Enter).

(6) Confirm the number with the

LIGHT

key (Enter).
(7) Set the number for the next digit.
(8) When settings for all the digits are complete , the ref erence value

starts flashing.

(9) Confirm the reference value with the

LIGHT

key (Enter). The buzz er
sounds and the setting ends. The tester changes its mode to
measurement of insulation resistances.

Repeat steps (1) to (9) to change other preset values.

22. Specifications (JIS C1302-2002 compliance)

Rating

Center Value Indicated (MΩ)
1st Effective Measuring Range (MΩ)
2nd Effective Measuring Range

Lower Limit
2nd Effective Measuring Range

Upper Limit (MΩ)
Lower Measuring Limit of

Resistance
Rated Current (mA)
AC Voltage Measuring Range (V)

Tolerances under the above conditions

Insulation resistance measurement:
±(2% of rdg + 6 dgt) within the 1st effective measuring range
± (5% of rdg + 6 dgt) within the 2nd effective measuring range (Lower limit)
±(5% of rdg) within the 2nd effective measuring range (Upper limit)
Zero value indicated: 6 dgt max.
AC voltage: ±(2% of rdg + 6 dgt)
Conductor resistance measurement: ±(2% of rdg + 8 dgt)
No-load voltage: within 130% of the rated voltage
Short-circuit current: 2 mA or less

Response time

Effect of temperature

Effect of humidity Within tolerance
Effect of external

magnetic field

Effect of AC component

Withstand voltage

Effect of vibration

Effect of shock

Effect of external
voltage

Possible number of
measurements

Protection against
water, solid matters,
and dust penetration

Item Limit

(MΩ)

(MΩ)

Digital indication: 3 sec or less
Bar graph indication (static) value: approx. 2 sec

± (2% or rdg  6 dgt)

1.2% or less of indication

10% or less of indication

There must not be an abnormality
(between electric circuits and outer case).

There is no structural damage and the difference in errors must be
100% or less of the tester’s intrinsic errors

There is no structural damage and the difference in errors must be
100% or less of the tester’s intrinsic errors

There must not be an abnormality.

Model Range Number of measurements
125 V/ 200 MΩ Approx. 1600
MY40-01 250 V/ 200 MΩ Approx. 1400
500 V/2000 MΩ Approx. 1000
1000 V/2000 MΩ Approx. 700

Class IP 40: Foreign substances of 1.0 mm or more in diameter
must not enter at all.

125V/200 MΩ 250V/200 MΩ

5

.0200 to 10.00

0 to.0199

10.01 to 200

0.125

1 to 1.2

5

.0500 to 20.00

0 to .0499

20.01 to 200

0.25

1 to 1.2

Standard test conditions

Ambient temperature and humidity: 23 ±5°C at 45 to 75% RH
Position : Horizontal (within 5 degrees)
Influence of external magnetic field: Earth magnetism
Battery voltage :
indicated.)

1st effective measuring range: maximum, center, and minimum
indicated values
Deviation from those values when ambient temperature is varied from
20°C by ± 20°C.

When the tester is left for 1 hour with the humidity at 90% RH
A change when the maximum, center, and minimum values of the first

effective measuring range are indicated and an external field of 400 A/m
DC is applied in the most affected direction.

A change when a capacitor of 5 mF ±10% is connected in parallel with a resistor
the value of which is determined from the rated measuring voltage and current,
and which is itself connected to the measuring terminals.

When a sine wave, or the like, is applied between the electric circuits
and the outer case at 5550 V AC and 50/60 Hz for 1 minute

When a vibration frequency of 25 Hz and a peak-to-peak amplitude of
1 mm is applied for 20 minutes in each of three directions that are
perpendicular to each other.

When a half-sine pulse shock of 1000 m/s
and reverse for 6 ms, three times in each of three directions that are
perpendicular to each other.

When an AC voltage 1.2-fold the rated measuring voltage at 50 Hz or 60
Hz is applied to the measuring terminals for 10 seconds with the MEAS
key being on and then off.

Test point: The minimum measurable resistance that can maintain the
rated measuring voltage.
Measuring time: Five seconds each with approx. 25 seconds between
measurements
Backlight: Off
Battery used: Manganese battery
Ambient temperature: 20 ±2 °C; Relative humidity: 65 ±20%
(Battery testing conditions in compliance with JIS C8501)

JIS C0920 compliance, with measuring probes attached to the tester.
(IEC 60529: Degrees of protection provided by enclosures)

500V/2000 MΩ

50

1.000 to 500

0 to .999

501 to 2000

0.5

1 to 1.2

0 to 600

Within effective range of the battery (the mark must not be

Test condition

From the instant the resistors whose values correspond to central
indication and zero indications are abruptly connected, to when
the pointer reaches a level within tolerance

1000V/2000 MΩ

50

2.000 to 1000

0 to1.999

1001 to 2000

2

0.5 to 0.6

2

is applied in both forward

24. Accessories

■ Standard Accessories

■ Optional Accessories

1. 99011

2.

3.

9. JK

4. 98052

5. GN

6. NW

7. NX

8. NZ

25. External Dimensions

Unit: mm

(apptox. inch)

27. Corrective Measures in Case of Failure

If the instrument does not operate properly after taking the corrective
measures shown below or any other failure that is not covered here
occurs, contact the vendor from which you purchased the instrument.

Failures

• The tester displays nothing after turning the function switch to the
on position.

• The display is light in color.

• The measured values are erroneous.

Items to Check

• The batteries are installed properly and their power levels are not
low.

• The measuring probes are connected correctly and are not dam­aged.

• Whether the failure reoccurs after turning off the power and retry­ing the operation.

23. General Specifications

Operation temperature
and humidity
Storage temperature
and humidity
Battery
External dimensions
Weight

0°C to 40°C at 90% RH or less (no condensation)

–10°C to 60°C at 70% RH or less (no condensation)

Four AA-size (R6)
Approx. 125 (W) × 103 (H) × 52.5 (D) mm
Approx. 420 g (main unit and batteries only)
Approx. 600 g
(main unit, batteries, protective cover, earth probe and line probe)

Safety standards

EMC standards
Effect of radiation

immunity

EN61010-1 and EN61010-2-31
Insulation class2,Pollution degree 2
Measurement category3
(CAT.3 maximum working voltage: 600 V AC)
Indoor use, Operating altitude: 2000m max. above sea level
EN55011 ClassB Group1
EN61326 ClassB
At the strength of radio-frequency electromagnetic field of
3V/m

• Insulation resistance measurement
1st effective measuring range : ± (5% of rdg +12dgt)
2nd effective measuring range : ± (10% of rdg +12dgt)

• AC Voltage measurement : ± (5% of rdg +12dgt)

• Conductor resistance measurement : ± (10% of range)

26. Maintenance

■ Storage Conditions

• Temperature and humidity:-10°C to 60°C at 70% RH or less

• Remove the batteries before storing the tester.

• Avoid storing the tester in a location where there is:
moisture; exposure to direct sunlight;
a high-temperature heat source nearby;
exposure to severe mechanical vibrations;
a large amount of dust and/or salt, or a corrosive gas.

■ Removal of Dirt
Do not use solvents (such as paint thinners or benzine) or
chemicals as they are likely to cause discoloration. Wipe off dirt with
a cloth dampened water or alcohol.

■ Calibration Cycle

It is recommended that the tester be calibrated once every year for
correct operation; ask Yokogawa to do the periodic calibration
for you.

Error Messages

Err.0: An internal operation failure.

Turn off the power and retry the operation.
* If the failure reoccurs, the tester needs repairing.

Err.1: Cannot save the comparator or memory settings.

Measurement functions other than the comparator and memory
functions operate normally.
Settings and data saved without the error indication (Err .1) can
be used.
* If the failure reoccurs, the tester needs repairing.

Err.2: An internal operation failure.

Turn off the power and retry the operation.
* If the failure reoccurs, the tester needs repairing.

IM MY40-E <2>