User’s

Manual

CL420

Clamp-on Process Meter

Thank you for purchasing our Clamp-on Process Meter.

This manual describes the specifications and handling precautions for a Clamp-on Process Meter.

Before using this product, thoroughly read this manual to get a clear understanding on proper use.

Store this manual in a place that facilitates ease of reference whenever necessary.

IM CL420-EN

1st Edition July 2012 (YMI)

Yokogawa Meters & Instruments Corporation

International Sales Dept.

Tachihi Bld. No.2, 6-1-3, Sakaecho, Tachikawa-shi,

Tokyo 190-8586 Japan

Phone: 81-42-534-1413, Facsimile: 81-42-534-1438

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

Phone: 1-800-888-6400 Facsimile: 1-770-254-0928

YOKOGAWA EUROPE B. V. (THE NETHERLANDS)

Euroweg 2, 3825 HD, Amersfoort, THE NETHERLANDS

Phone : 31-88-4641000 Facsimile : 31-88-4641111

YOKOGAWA AMERICA DO SUL LTDA. (BRAZIL)

Phone: 55-11-5681-2400 Facsimile: 55-11-5681-4434

YOKOGAWA ENGINEERING ASIA PTE. LTD. (SINGAPORE)

Phone: 65-6241-9933 Facsimile: 65-6241-2606

YOKOGAWA MEASURING INSTRUMENTS KOREA

CORPORATION (KOREA)

Phone: 82-2-551-0660 to -0664 Facsimile: 82-2-551-0665

YOKOGAWA AUSTRALIA PTY. LTD. (AUSTRALIA)

Phone: 61-2-8870-1100 Facsimile: 61-2-8870-1111

YOKOGAWA INDIA LTD. (INDIA)

Phone: 91-80-4158-6000 Facsimile: 91-80-2852-1441

YOKOGAWA SHANGHAI TRADING CO., LTD. (CHINA)

Phone: 86-21-6239-6363 Facsimile: 86-21-6880-4987

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

Phone: 973-17-358100 Facsimile: 973-17-336100

YOKOGAWA ELECTRIC CIS LTD. (RUSSIAN FEDERATION)

Phone: 7-495-737-7868 Facsimile: 7-495-737-7869

IM3E-2011.7

Printed in Japan

IM CL420-EN <P1>

1. Regarding Safe Use of This Product

When operating the instrument, be sure to observe the cautionary nots given below to ensure correct and safe use of the instrument. If you use the instrument in any way other than as instructed in this manual, the instrument's protective measures may be impaired.

Yokogawa is by no means liable for any damage resulting from use of the instrument in contradiction to these cautionary notes.

The following safety symbols are used on the instrument and in this 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.

Danger! Handle with Care.

This mark indicates that operator must refer to an explanation in the instruction manual in order to avoid risk of injury or death of personnel or damage to the instrument.

Do not apply around or remove from HAZARDOUS

LIVE conductors.

This symbol indicates DC voltage/current.

This symbol indicates ON/OFF (power).

WARNING

Strictly observe the following cautionary notes in order to avoid the risk of injury or death of personnel or damage to the instrument due to hazards such as electrical shock.

• Do not use this product in a place where an explosive gas or vapor is present.

• To avoid a short-circuit or an accident to personnel, use this product within the RATED circuit-to-earth voltage.

If you mistakenly clamp a wire whose voltage exceeds the RATED circuit-to-earth voltage of this product, dangerous high voltage may appear at the analog output terminal.

For example, if you short the item under measurement with a metal part of the transformer jaw, an arc discharge may occur, which could damage the item under measurement.

• Do not use the product when there are raindrops or droplets of condensed water on its surface, or if your hands are wet.

• Barrier is for to avoid touching the HAZARDOUS LIVE conductor.

Be careful not to across the Barrier when using the instrument.

• Safety protectors such as rubber-insulated gloves should be worn to prevent electrical shock when using the instrument.

• Do not open a Battery cover during a measurement.

• Do not measure AC currents.

• Do not use deteriorated or defective output cables.

• Do not use the instrument if the case or cable is damaged or not attached.

Do not attempt to repair/modify the product yourself, as doing so is extremely dangerous.

Should an abnormality or failure in the product be found, contact the vendor from which you purchased the product.

CAUTION

• The clamping JAWS is precision assembled to ensure high performance. When using the clamp, do not apply any intense mechanical shock, vibration or force to the clamping JAWS.

• If dust or any other foreign matter gets in the clamping

JAWS, do not close the clamping cores tight.

First remove the dust and then make sure the clamping cores on both sides close smoothly.

CAUTION

• Do not expose the instrument to direct sunlight, high temperature, humidity or dew.

• This instrument is not water/dust proof. Do not use it in a dusty environment or where it will get wet.

• Always turn off power after using the instrument.

If the instrument is not used for prolong period, remove the batteries.

• Use a damp cloth or cotton swab with neutral detergent or water for cleaning the instrument.

Do not use abrasives or solvents.

WARNING

Do not use the CL420 for measurements in locations falling that fall under Measurement Categories

II, III, and IV.

The CL420 is designed for measurement category O.

Measurement category

Measurement category

[

O

None

Other

]

CAT. II

CAT. III

CAT. IV

Description Remarks

Other circuits that are 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 lowvoltage installation.

Circuits not connected to a mains power source.

Appliances, portable equipment, etc.

Distribution board, circuit breaker, etc.

Overhead wire, cable systems, etc.

Entrance

Cable

CAT. IV

Internal Wiring

Distribution

Board

CAT. III CAT. II

T

O

Fixed Equipment, etc.

Equipment

Outlet

2. Feature

● Instrumentation signal (DC4–20mA) measurement

● DC current (0-100mA) measurement without breaking

the electrical circuit.

● LED light for illuminating the measurement spot

● Auto-power-off function

● Display (calculation) of Span (%)

● Analog output function to output the measured results

to the Recorder, Digital multimeter (DMM) or Logger.

● Data hold function

3. Specification

3.1 Accuracy

Condition: 23±5ºC, 75% RH or less

(1) DC current (AUTO RANGE)

Accuracy : ±(% of reading + digits)

Range Display range

(mA)

Guaranteed accuracy

(mA)

20 mA 0.00 to ±21.49

0.00 to ±21.49

100 mA ±21.0 to ±126.0 ±21.0 to ±120.0

DCA

Accuracy

0.2 + 5 *1

1.0 + 5

Condition of accuracy:

Turning on and opening/closing operation of jaws are performed 2 or 3 times.

After Zero-adjustment

*1: The accuracy for the 20 mA range is the result of averaging five measurements.

Response time:

Approx. 1.5 seconds

(Approx. 2.5 seconds at range change)

(2) Analog output function

Output voltage

(mV)

Accuracy

(mV)

20 mA 0.00 to ±21.49 0.0 to ±214.9

100 mA ±21.0 to ±126.0 ±210 to ±1260

DCA Accuracy

± 0.5

Accuracy of

± 3

Response time:

Add approx. 0.5 s to the current measurement response time.

• To output DC voltage (10 mV/mA) corresponding to

the reading.

• To output 0 mV at range change.

• 1300mV is output when the display shows “OL”.

(-1300mV for “-OL”)

• Output impedance : approx. 5kΩ

3.2 General Specification

Safety standards: EN 61010-1, EN 61010-2-030,

EN 61010-2-032

Environmental conditions:

Operating altiude 2000 m or less,

Indoor use, Pallution degree 2

EMC standards: EN 61326-1 ClassB, EN 61326-2-2

Display: LCD

Measurement cycle: Approx. 0.6 seconds / one time

Operating temperature and humidity:

-10 to +50ºC, 85%RH or less (no condensation)

Storage temperature and humidity:

-20 to +60ºC, 85%RH or less (no condensation)

Power supply:

Battery life:

Auto-power-off:

AA-size battery x 4 pcs.

(The use of alkaline LR6 is recommended.)

Approx. 60 hours continuous (Using alkalin battery, Backlight and LED light OFF)

Power off function operates in approx.

10 min. after the last switch operation.

This function is disabled when a cord is being connected to the OUTPUT terminal.

Temperature coefficients:

Add 0.1 x specified accuracy/ ºC

(at -10 to 18ºC, 28 to 50ºC)

Insulation resistance:

100 MΩ or more/ 1000 DCV

Between electrical circuit (core) and case

Withstand voltage:

2210 ACV for 5 sec.

Between electrical circuit (core) and case

Measurble conductor diameter :

Ф6 mm maximum

The RATED circuit-to-earth voltage : 42 Vpk

Maximum allowed current : 120 DC mA

Influence of external magnetic field :

Earth magnetism (0.20 mA) or less

Dimensions:

Main unit Approx. 111(H) x 61(W) x 40(D) mm

Clamp sensor Approx. 104(H) x 34(W) x 20(D) mm

Cable length Approx. 700 mm

Weight: Approx. 290 g (including batteries)

Accessory: Soft case (93045)

AA-size Alkaline battery (LR6) 4 pcs.

User’s manual

Optional accessory: Output cable (98076)

Output cable for screw terminal

(98077)

4. Components

4.1 Main unit and Clamp sensor

<Main unit>

LED light

LCD Cable

<Clamp sensor>

Transformer

Jaws (core)

Polarity mark

Barrier

Light key

Trigger

Zero ADJ. key

DISP key

(to switch displays)

Power key

Data hold key

Analog output terminal

4.2 LCD

Zero ADJ.mark

Sub display

Battery level indicator

Hold mark Main display

5. Before making measurement

5.1 Turning ON the Power key

Press the Power key for approx. 2 seconds.

(1) Check the remaining battery.

For further details, see “8. Battery Replacement”.

(2) Check that Data hold function is not effective.

( mark is disappeared.)

5.2 Turning OFF the Power key

Press the Power key again. (Approx. 2 seconds)

For further details, see “7.2 Auto-power-off function”.

6. Operating instructions

WARNING

● Do not use the instrument if it is damaged.

Doing so poses a risk of electrical shock and may

result in inaccurate measurements.

● When using the analog output function, do not use

any one other than dedicated output cable (98076 or

98077).

● Be careful not to across the Barrier when using the

instrument.

CAUTION

● Do not use the instrument with currents that exceed

the maximum allowed current.

Doing so may damage the instrument.

● A dirty clamp sensor can cause large measurement

errors. Check that the clamp sensor, the item under

measurement, and other relevant items are not dirty

before making measurements.

We recommend that you use an air blower to clean

the clamp sensor jaws (core).

● Take sufficient care to not to apply shock, vibration or

excessive force when opening and closing the clamp

sensor. Otherwise, accurate measured results may

not be obtained. Please open and close the sensor

lightly.

6.1 For Precise Measurements

● Before measurement, with the power turned on, open

and close the clamp sensor two or three times.

● To reduce the influence of temperature, noise, and

other external factors on measurements, perform

“ zero adjustment ”.

● Drastic changes in input current or excessive current

can cause the zero point to drift. Disconnect the

clamp sensor from the conductor to perform

“ zero adjustment ”.

● Position the conductor in the center of the clamp to

make measurements.

● Check that the jaws are fully engaged.

● We recommend that you make several measurements

and compare the results to reduce the influence of

measurement conditions.

[ Zero Adjustment ]

To reduce the effects of external magnetic fields, move the clamp sensor as close to the conductor under measurement as possible, align the polarity arrow with the measurement direction, and press the ZERO ADJ key.

(Do this without clamping the conductor and with the transformer jaws closed.)

The mark is displayed on the LCD for approximately 1 second.

6.2 Measurement

Before making measurements, be sure to open and close the clamp sensor and perform zero adjustment.

See section 6.1, "For Precise Measurements."

Push the trigger to open the transformer jaws.

Clamp one of the conductors that you will measure.

(see the figure below)

The measured current appears in the main display of the LCD.

• If the measured current is negative, the current is

flowing in the direction opposite to the clamp arrow.

< correct > < wrong >

6.3 Span display (20 mA Range only)

The sub-display shows percentage value as the basis of 4mA is 0% and 20mA is 100%.

The table at the right shows the relationship between

Span values (%) and the measured values (mA).

Measured values

(mA)

-20.00

0.00

2.00

4.00

12.00

20.00

100.0

Span display

(%)

100.0

-25.0

-12.5

0.0

50.0

100.0

---

The percentage value is calculated based on the following formula, assuming the measured value as X.

Span display range =(|X| - 4.00)×6.25 (%)

6.4 Switching between the Main Display and

Sub Display (20 mA range only)

CAUTION

Check that the main display (unit) and sub display (unit) are displaying values properly.

Press the DISP key to switch between the main and sub displays.

6.5 Over range (load) indication

When the input exceeds the max measuring range

(126.0mA), "OL" or “-OL (for negative values)” is indicated on the display.

When the Range reaches to the 100mA, bars “---” are displayed instead of the percentage value.

7. Other functions

7.1 Data Hold Function

This is a function to freeze the measured value on the display.

Press the Data hold key once to freeze the reading.

The reading will be held regardless of subsequent variation in input.

The Data hold mark " " is indicated on the display while the instrument is in the Data Hold mode. To exit

Data Hold mode, press the Data hold key again.

7.2 Auto-power-off function

The instrument automatically powers off approx. 10 minutes after the last operation. This function is disabled while the cord is being connected to the analog output terminal.

[ To cancel the Auto-power-off function ]

Hold down the Data hold key while pressing the power key.

The instrument is turned on and then “ is indicated for approx. one second.

(P.oFF)”

[ To enable the Auto-power-off function once again ]

Press the power key to turn off power.

Press the power key (approx. 2 sec.) to turn on power.

(The Auto-power-off function is enabled again.)

7.3 Backlight and LED light

Press the Light key to turn on or off the LED light and

LCD backlight. These lights automatically turn off when 2 minutes elapse after the last key operation.

[ To cancel the auto off function ]

Hold down the Data hold key while pressing the power key.

The instrument is turned on and then “ is indicated for approx. one second.

(L.oFF) ”

[ To enable the Auto-power-off function once again ]

Press the power key to turn off power.

Press the power key (approx. 2 sec.) to turn on power.

(The Auto-power-off function is enabled again.)

7.4 Analog output function

DC voltage signal corresponding to the measured

(display) result is output from the Analog output terminal (10 mV/mA).

It can be checked on a Recorder, a Digital multimeter

(DMM) or Logger connected to the instrument by using

Output cable (98076 or 98077).

When connecting the Output cable to the instrument, the sub-display shows “ (OUT)” for 1 sec.

When making measurements for long periods of time:

• Leave the instrument for the warm-up period of

several tens of minutes after powering it on, and

then start a recording.

• Readings will vary when the ambient temperature

changes. In this case, the temperature coefficients

specified at clause 3 and fluctuations at zero

(about 20 counts fluctuate when temperature

changes by 10ºC) should be taken into

consideration.

DMM etc.

Output Cable

(98076)

8. Battery replacement

8.1 Battery State display

A decrease in the battery voltage is display in the following four steps.

Replace the batteries as soon as the low battery mark

“ (Blink) ” appears, to avoid inaccurate reading.

1 2 3 4

(Blink alarm)

The use of alkaline batteries (four) is recommended.

8.2 Battery Replacement

WARNING

● Ensure that the Clamp sensor is disconnected from

the object under test, and that the instrument is

power off when opening the Battery cover for battery

replacement.

(Remove the optional output cable if you are using it.)

CAUTION

● Do not mix batteries of different types or new batteries

with used ones.

● Make sure the polarities of the new batteries are exactly

as shown on the battery holder.

When the low battery mark “ (Blink) ” appears, measurement accuracy is not guaranteed.

Replace the batteries quickly.

• If the battery is completely flat, the LCD will not turn

on, and the mark will not appear.

[ How to replace batteries ]

(1) Power off the instrument.

(2) Remove the screw on the back of the casing and

remove the battery cover.

(3) Take the batteries out of the housing and replace

the batteries with new ones.

(4) Close the casing and fasten it with the screw.

Screw

9. Meintenance

[ Contact of Services ]

Please contact one of the Yokogawa sales offices listed of this manual or the sales representative from which you purchased the instrument.

[ Calibration Cycle ]

It is recommended that the instrument be calibrated once every year.

10. Disposing the Product

10.1 Disposing the Product

Waste Electrical and Electronic Equipment

(WEEE), DIRECTIVE 2002/96/EC

(This directive is valid only in the EU.)

This product complies with the WEEE Directive

(2002/96/EC) marking requirement.

The following marking indicates that you must not discard this electrical/electronic product in domestic household waste.

Product Category

With reference to the equipment types in the

WEEE directive Annex 1, this product is classified as a “Monitoring and Control instrumentation” product.

When disposing products in the EU, contact your local Yokogawa Europe B. V. office.

Do not dispose in domestic household waste.

10.2 How to Replace and Dispose the Batteries

New EU Battery Directive, DIRECTIVE

2006/66/EC

(This directive is valid only in the EU.)

This is an explanation about the new EU Battery

Directive (DIRECTIVE 2006/66/EC).

This directive is valid only in the EU. Batteries are included in this product.

When you remove batteries from this product and dispose them, discard them in accordance with domestic law concerning disposal.

Take a right action on waste batteries, because the collection system in the EU on waste batteries are regulated.

Battery type: Alkaline dry cell

Notice:

This marking means they shall be sorted out and collected as ordained in ANNEX II in DIRECTIVE

2006/66/EC.

How to remove batteries safely:

For further details, see " 8. Battery Replacement".

11. "Measure for Administration of the Pollution Control of

Electronic Information Products" of the People's Republic of China

This User’s Manual explains the Prevention of Pollution Control of Electronic Equipment Method in China.

This manual is valid only in China.

产品中有毒有害物质或元素的名称及含量

部件名称 铅

（Pb）

汞

（Hg）

有毒有害物质或元素

镉

（Cd）

六价铬

（Cr(VI)）

多溴联苯

（PBB）

多溴二苯醚

（PBDE）

框架（塑料）

线路板 ASSY

CABLE

电池

选购

输出 CABLE

98076

○

×

×

×

×

○

○

×

×

×

○

×

×

×

×

○

○

×

×

×

○

○

○

○

○

○

○

○

○

○

输出 CABLE

98077

× × × × ○ ○

○ ：表示该部件的所有均质材料中的有毒有害物质的含量均在 SJ/T 11363-2006 标准中所规定的限量以下。

× ： 表示该部件中至少有一种均质材料中的有毒有害物质或元素的含量超过 SJ/T 11363-2006 标准所规定

的限量要求。

环保使用期限 :

该标识适用于 2006 年 2 月 28 日颁布的《电子信息产品污染控制管理办法》以及

SJ/T 11364–2006《电子信息产品污染控制标识要求》中所述、在中华人民共和国销

售的电子信息产品的环保使用期限。

只要您遵守该产品相关的安全及使用注 意事项、在自制造日起算的年限内、则不会因

产品中有害物质泄漏或突发变异、而造成对环境的污染或对人体及财产产生恶劣影响。

注） 该年数为“环保使用期限”、并非产品的质量保证期。零件更换的推荐周期、

请参照使用说明书。

IM CL420-EN <P2>