YOKOGAWA 701931 User manual

User’s
Manual
IM 701931-01E
8th Edition
701931
Current Probe

i
IM 701931-01E
Thank you for purchasing the Current Probe (Model 701931).
This instruction manual contains useful information about the instrument’s
functions and operating procedures as well as precautions that should be
observed during use. To ensure proper use of the instrument, please read this
manual thoroughly before beginning operation.
After reading the manual, keep it in a convenient location for quick reference
whenever a question arises during operation.
List of Manuals
The following manuals are provided for the Current Probe (Model 701931).
Manual Title Manual No. Notes
701931 Current Probe
User’s Manual
IM 701931-01E This manual.
701931 Current Probe
User’s Manual
IM 701931-92 Document for China
701931 Current Probe
User’s Manual
IM 701931-93Z2 Document for Korea
The “E” and “Z2” in the manual numbers are the language codes.
Contact information of Yokogawa offices worldwide is provided on the following
sheet.
Document No. Description
PIM113-01Z2 List of worldwide contacts
Revisions
1st Edition: August, 2003
2nd Edition: September, 2004
3rd Edition: November, 2005
4th Edition: October, 2013
5th Edition: October, 2014
6th Edition: November, 2015
7th Edition: January, 2016
8th Edition: October, 2017
8th Edition: October 2017 (YMI)
All Rights Reserved, Copyright © 2003 Yokogawa Electric Corporation
All Rights Reserved, Copyright © 2013 Yokogawa Test & Measurement Corporation

ii IM 701931-01E
Checking the Contents of the Package
If the wrong instrument or accessories have been delivered, or if some
accessories are missing or defective, contact the dealer from which you
purchased them.
Current Probe (Model 701931) Main Body
Accessories
• User’smanuals 1set
• Carryingcase
Safety Precautions
This probe meets the requirements as given in the IEC-61010.
The following general safety precautions must be observed during all phases of
operation, service, and repair of this instrument. If this instrument is used in a
manner not specified in this manual, the protection provided by this instrument
may be impaired. Also, YOKOGAWA assumes no liability for the customer’s
failure to comply with these requirements.
The following symbols are used on this instrument.
To avoid injury, death of personnel or damage to the instrument, the
operator must refer to an explanation in the User’s Manual or Service
Manual.
Both direct and alternating current.
Do not apply around or remove from HAZARDOUS LIVE conductors.

iii
IM 701931-01E
Important Information for Users
In order to ensure safe operation and to obtain maximum performance from the
unit, observe the cautions listed below.
WARNING
Connection with Power Supply and Protective Grounding
Connect the power supply to the probe power supply terminal of a
waveform measuring instrument such as YOKOGAWA DL/DLM series, or
use the Power Supply (Model 701934).
Connecting the Probe to the Item under Test
• Ifyouneedtotouchthecircuitwithyourhand,firstcutthepowertothe
circuit and confirm that it is not carrying any voltage.
• Toavoidshortcircuitsandpersonalinjurywhentheclampisopenor
measurement is being performed, do not apply the clamp to any bare
conductors.
Restrictions on the Measuring Instrument
Read and observe all warnings and precautions relating to electrical safety
for the measuring instrument being connected to the probe.
Do Not Operate When Wet
To prevent electric shocks, do not allow the unit to become wet and do not
use the unit when your hands are wet.
Do Not Operate Near Flammable Materials
Do not operate the probe in the presence of flammable or explosive liquids
or vapors.
Do Not Use When Removed from the Case
To avoid electric shock or fire, never use the probe if the case has been
removed.
* Do not exceed the following levels: 30 Vrms, 42.4 Vpeak, and 60 VDC.
CAUTION
• Donotsubjecttheunittovibrationsorshocksduringtransportor
handling. Be especially careful to avoid dropping the unit.
• Donotstoreoroperatetheunitwhereitwillbeexposedtodirect
sunlight, high temperature, high humidity, or condensation. If exposed
to such conditions, the unit may become damaged, the insulation may
deteriorate, and the unit may no longer satisfy its specifications.
• Beforeusingtheunit,inspectitandchecktheoperationtomakesure
that it was not damaged due to poor storage or transport conditions. If
damage is found, contact your dealer or YOKOGAWA representative.

iv IM 701931-01E
• Thisinstrumentisnotwaterproofordustproof.Donotusetheunitina
wet or dusty environment.
• Thesensorheadisaprecisionassemblyincludingamoldedcomponent,
a ferrite core, and a Hall effect element. It may be damaged if subjected
to sudden changes in ambient temperature, or mechanical strain or
shock, and therefore great care should be exercised in handling it.
• Thematchingsurfacesofthesensorheadareprecisionground,
and should be treated with care. If these surfaces are scratched,
performance may be impaired.
• Ifthereisanytypeofdustordirtonthematchingsurfacesofthesensor
head, measurements may be affected. Wipe it away gently with a soft
cloth.
• Inordertoavoiddamagingthesensorcablesdonotbendorpullthe
sensor cable or power supply cable.
• Currentsensorscanbedamagedbystaticelectricity.Becarefulnotto
apply static electricity to current sensors. Below are some ways you
could apply static electricity.
• Touchingthesensorheadwithanobjectchargedwithstaticelectricity
• Touchingthesensorheadwithanobjectwhoseelectricpotentialis
different
• Auserchargedwithstaticelectricitytouchingthecoresurfacewhen
cleaning the matching surfaces of the sensor head
(When cleaning the surfaces, take static electricity measures such as
wearing an antistatic wrist strap.)
• Gentlywipedirtfromthesurfaceoftheunitwithasoftclothmoistened
with a small amount of water or mild detergent. Do not try to clean
the unit using cleaners containing organic solvents such as benzene,
alcohol, acetone, ether, ketones, thinners, or gasoline. They may cause
discoloration or damage.
• WhenthepowerisON,keepthecoresectionofthesensorclosed,
except when clamping it onto the conductor to be measured. The facing
surface of the core section can be scratched while it is open.
Note
• Accuratemeasurementmaybeimpossibleinlocationssubjecttostrongexternal
magnetic fields, such as near transformers and high-current conductors, or in
locations subject to strong external electric fields, such as near radio transmission
equipment.
• Dependingonthecurrentfrequencythatismeasured,oscillationmayoccur,but
this has no effect on measurements.

v
IM 701931-01E
Sales in Each Country or Region
Waste Electrical and Electronic Equipment
Waste Electrical and Electronic Equipment (WEEE), Directive
(This directive is valid only in the EU.)
This product complies with the WEEE directive marking requirement.
This 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, this
product is classified as a “Monitoring and control instruments”
product.
When disposing products in the EU, contact your local Yokogawa
Europe B.V. office.
Do not dispose in domestic household waste.
Authorized Representative in the EEA
Yokogawa Europe B.V. is the authorized representative of Yokogawa Test &
Measurement Corporation for this product in the EEA. To contact Yokogawa
Europe B.V., see the separate list of worldwide contacts, PIM 113-01Z2.

vi IM 701931-01E
The following markings are used in this manual.
Improper handling or use can lead to injury to the user or
damage to the instrument. This symbol appears on the
instrument to indicate that the user must refer to the user’s
manual for special instructions. The same symbol appears in
the corresponding place in the user’s manual to identify those
instructions. In the manual, the symbol is used in conjunction
with the word “WARNING” or “CAUTION.”
WARNING Describes precautions that should be observed to prevent
serious injury or death to the user.
CAUTION Describes precautions that should be observed to prevent
minor or moderate injury, or damage to the instrument.
Note Provides important information for the proper operation of the
instrument.

1
2
vii
IM 701931-01E
Contents
List of Manuals................................................................................................................... i
Checking the Contents of the Package............................................................................. ii
Safety Precautions............................................................................................................ ii
Sales in Each Country or Region...................................................................................... v
The following markings are used in this manual. ............................................................. vi
Chapter 1 701931 Current Probe
Product Overview...........................................................................................................1-1
Features.........................................................................................................................1-1
Names of Parts ..............................................................................................................1-2
Description of Parts........................................................................................................1-3
Measurement Procedure ...............................................................................................1-4
Notes on Use ......................................................................................................1-4
Preparations for Measurement ...........................................................................1-5
Demagnetizing and Zero Adjustment..................................................................1-6
Measurement Procedure ....................................................................................1-7
Specifications...............................................................................................................1-10
Product Specifications ......................................................................................1-10
Applicable Standards........................................................................................1-11
Chapter 2 Malfunction? First, Investigate.
Corrective Action to be Taken in Case of an Abnormality ..............................................2-1

1-1
IM 701931-01E
1
2
Chapter 1 701931 Current Probe
Product Overview
This unit can be directly connected to a BNC input connector of a waveform
measuring instrument such as YOKOGAWA DL/DLM series, and by clamping
it to a conductor to be measured, allows the current waveform to be easily
captured.
Features
• Highlyaccuratecurrentdetection
• Easycurrentmeasurement
• Widebandfrequencycharacteristics;DCto2MHz
• Wideclamppermitsmeasurementofhighcurrentlevels
• Easyprotectfunctionduringexcessiveinput
701931 Current Probe

1-2 IM 701931-01E
Names of Parts
Terminator
Sensor
Power Supply Cable
Sensor Cable
LOCK Indication
2
1
4 (internal)
3
5
6
7
8
2
UNLOCK Indication
Current Direction Indication

1-3
IM 701931-01E
1
2
Description of Parts
1 Clamp
The part which clamps to the conductor to be measured.
2 Clamp Lever
The lever for opening and closing the clamp. Make sure to open or close the
clamp only by using the clamp lever.
3 Clamp Lock
Locks the clamp in place when it is closed.
4 Sensor Head
This clamps the conductor being measured, and carries out the actual current
measurement. It is a precision assembly including a molded component,
a ferrite core, and a Hall effect element. It may be damaged if subjected to
sudden changes in ambient temperature, or mechanical strain or shock, and
therefore great care should be exercised in handling it.
5 Demagnetizing Switch (DEMAG)
If the core has been magnetized by switching the power ON and OFF,
or by an excessive input, this switch demagnetizes it. Always carry out
demagnetizing before measurement. The demagnetizing process takes about
three seconds. During demagnetizing, a demagnetizing waveform is output.
6 Zero Adjustment Dial (ZERO ADJ)
Use the zero adjustment dial to correct for the effect of a voltage offset or
temperature drift on the unit. When performing measurements, always carry
out a zero adjustment after demagnetizing.
7 Output Connector
The current waveform of the measured conductor is output at a constant rate
(0.01 VA in conjunction with the waveform measuring instrument with an input
impedanceof1MΩ.)
Connect to the BNC input connector of the waveform measuring instrument.
Note
• Theoutputofthisunitisterminatedinternally.Useahigh-impedanceinputtothe
measuringinstrument.Withaninputimpedanceof50Ω,accuratemeasurement
is not possible.
• IfusingBNC-bananaplugorsimilaradapterstoconnecttoinputterminalsother
than BNC connectors, make sure the polarity is correct.
• Turntheclampleveruntilitclicks,andcheckthatitislockedsecurely.
8 Power Plug
Connect the power plug to the receptacle on the Power Supply (Model
701934) to supply power to the sensor and terminator.
701931 Current Probe

1-4 IM 701931-01E
Measurement Procedure
Notes on Use
WARNING
Connection with Power Supply
Connect the power supply to the probe power supply terminal of a
waveform measuring instrument such as YOKOGAWA DL/DLM series, or
use the Power Supply (Model 701934).
Connecting the Probe to the Item under Test
• Ifyouneedtotouchthecircuitwithyourhand,firstcutthepowertothe
circuit and confirm that it is not carrying any voltage.
• Toavoidshortcircuitsandpersonalinjurywhentheclampisopenor
measurement is being performed, do not apply the clamp to any bare
conductors.
• Becarefulnottodamagetheinsulationsurfacewhiletakingmeasurements.
• Readandobserveallwarningsandprecautionsrelatingtoelectrical
safety for the measuring instrument being connected to the probe.
Do Not Operate When Wet
To prevent electric shocks, do not allow the unit to become wet and do not
use the unit when your hands are wet.
Do Not Operate Near Flammable Materials
Do not operate the probe in the presence of flammable or explosive liquids
or vapors.
Do Not Use When Removed from the Case
To avoid electric shock or fire, never use the probe if the case has been
removed.
* Do not exceed the following levels: 30 Vrms, 42.4 Vpeak, and 60 VDC.

1-5
IM 701931-01E
1
2
Preparations for Measurement
CAUTION
When using the Current Probe (Model 701931), you can only connect as
many active probes simultaneously to the Power Supply (Model 701934)
or the YOKOGAWA instruments probe power supply connector as allowed
depending on the current value of the conductor.
The current consumption of the Current Probe (Model 701931) is
dependent upon the measured current value. Do not let each active
probe’s total current consumption exceed the current regulated by the
Power Supply (Model 701934) or the YOKOGAWA instruments probe
power supply connector (see figure below).
0
–100
–100 0 100
100
200
200
300
300
400
400
500 600 700
500
600
–200
–200
–300
–300
–400
–400
–500
–600
–500–600–700
Positive AC (50 Hz) power
Negative AC (50 Hz) power
Positive DC power
Negative DC power
Current to be measured (A)
Current consumption vs. current to be measured (typical)
Current Consumption (mA)
For the probe power rating of each model, please refer to “Relationship
between the current being measured and probe’s current cunsumption” link
of the following website.
http://tmi.yokogawa.com/products/oscilloscopes/current-probes
1. Have the Power Supply (Model 701934), and oscilloscope or recorder for
waveform measurement ready.
2. Turn the power switch OFF and connect the power cord.
3. Connect the power plug of the 701931 to the power receptacle of the
701934.
4. Turn the 701934 power switch ON, and check that the front panel power
indicator lights.
Note
The output of this unit is terminated internally. Use a high-impedance input to the
measuringinstrument.Withaninputimpedanceof50Ω,accuratemeasurement
is not possible. When power is supplied to the 701931, a demagnetizing waveform
might be generated
701931 Current Probe

1-6 IM 701931-01E
Demagnetizing and Zero Adjustment
CAUTION
• Whendisconnectingtheoutputconnector,besuretoreleasethelockbefore
pulling the connector. Forcibly pulling the connector without releasing the lock,
or pulling on the cable will result in damage to the terminator.
• IfusingBNC-bananaplugorsimilaradapterstoconnecttoinputterminalsother
than BNC connectors, make sure the polarity is correct.
• Donotdemagnetizewhentheclampisconnectedtoaconductor.Doingso
might damage the components of the circuit being measured.
• Donotbeginsupplyingpowertothe701931aftertheclamphasbeenconnected
to a conductor. Doing so might damage the components of the circuit being
measured.
1. With the waveform measurement instrument input at ground, adjust the
trace to the zero position.
2. Set the input coupling of the waveform measurement instrument to DC.
3. Connect the output connector of the 701931 to the input connector of the
waveform measurement instrument. Turn the clamp lever until it clicks,
and check that it is locked securely.
4. Without clamping the conductor to be measured, press the clamp
lever until the LOCK indication appears (and the UNLOCK indication
disappears), and then check that the clamp is properly closed.
5. Press the demagnetizing switch (DEMAG) on the terminator.
6. Turn the zero adjustment dial on the terminator to adjust the trace to the
zero position.
Note
• Theoutputofthisunitisterminatedinternally.Useahigh-impedanceinputtothe
measuringinstrument.Withaninputimpedanceof50Ω,accuratemeasurement
is not possible.
• OscillationmayoccurwhenyouexecuteDEMAG,butthishasnoeffecton
measurements.
• Thepositivesideofthewaveformthatisgeneratedwhenyouexecute
DEMAG may not be symmetrical to the negative side, but this has no effect on
measurements.

1-7
IM 701931-01E
1
2
Measurement Procedure
CAUTION
• Themaximumcontinuousinputrangeisbasedonheatthatisinternally
generated during measurement. Never input current in excess of this
level. Doing so may result in damage to the probe.
• Themaximumcontinuousinputrangevariesaccordingtothefrequency
of the current being measured. See page1-10, “Product Specifications.”
• Ifexcesscurrentisinput,generatedheatactivatesabuilt-insafety
function that blocks normal output. If this happens, remove the input
immediately (remove the sensor from the conductor being measured, or
reduce the input current to zero). Wait until the sensor has had sufficient
time to cool before resuming operation.
• Heatgeneratedbyaninputcurrentwhosefrequencyis1kHzorhigher
is mainly due to self-heating of the sensor head. In this case, the
protection function is not activated. Therefore, be careful of burns, short
circuits, and other accidents or sensor damage and the like caused by
the temperature increase.
• Ifyoucontinuouslyinputacurrentevenifitisbelowthemaximum
current value established by the maximum continuous input range,
the self-heating of the sensor may cause the safety function of the
instrument to activate in order to prevent damage to the instrument.
• Athighambienttemperatures,thebuilt-insafetycircuitmayactivateat
current input levels below the rated continuous maximum.
• Continuousinputofcurrentexceedingtheratedmaximum,orrepeated
activation of the safety function may result in damage to the unit.
• Thespecificationsindicatingthemaximuminputrangeliststhe
maximum peak current at 700 Apeak when non-continuous in addition to
the continuous maximum input range. This indicates an upper waveform
response limit of 700 Apeak. Use the sensor at the RMS current input
levels that is within the rated continuous maximum.
• Opentheclamponlybyusingclamplever.
• Tomaintaintheprobeaccuracywithinthespecificationsandtoverify
that correct measurement results are being obtained, periodic calibration
is necessary. The calibration period varies depending on your operating
environment and the frequency of use. We recommend that you set
a calibration period according to the frequency of use and ask us to
calibrate it periodically.
701931 Current Probe

1-8 IM 701931-01E
1. Check that the system is safe, and that the preparations described in the
preceding section have been carried out.
2. Pull the sensor opening lever so that the sensor head opens.
3. Align the sensor so that the current direction indication corresponds to
the direction of current flow through the conductor to be measured, and
clamp so that the conductor is in the center of the sensor aperture.
4. Press the clamp lever on the sensor head until the LOCK indicator
appears (and the UNLOCK indication disappears), and check that the
opening lever is firmly locked and the clamp is securely closed.
5. It is now possible to monitor the current waveform. The output voltage
rate of the 701931 is 0.01 V/A. Convert the voltage sensitivity of the
waveform observation instrument to current sensitivity. For example, if the
voltage sensitivity is 10 mV/DIV, the current sensitivity is 1 A/DIV.
Note
• Theoutputofthisunitisterminatedinternally.Useawaveformmeasurement
instrumentwithaninputimpedanceofatleast1MΩ.
• Immediatelyafterpoweringon,thisunitmaybesubjecttoanappreciableoffset
drift due to the effect of self-heating. To counteract this, allow the unit to warm up
for about 30 minutes before carrying out measurement.
• Whenperformingcontinuousmeasurements,beawarethattheoffsetvoltage
drifts depending on factors such as the ambient temperature.
• Undercertaincircumstances,oscillationmayoccuriftheprobeisconnectedto
the Power Supply (Model 701934) while the power supply is ON. In such cases,
oscillation can be stopped and operation restored to normal by opening and
closing the clamp with the clamp lever.
• Dependingonthemeasuredcurrentvalueoritsfrequency,resonantsounds
may be generated from the clamp. Unless there is dirt or foreign matter on the
matching surfaces of the sensor head, this will have no effect on measurement.
• Thereadingmaybeaffectedbythepositionwithintheclampapertureofthe
conductor being measured. The conductor should be in the center of the clamp
aperture.
• Whencarryingoutmeasurement,presstheclampleveruntiltheLOCK indication
appears (and the UNLOCK indication disappears), and check that the clamp is
properly closed. If the clamp is not properly closed, accurate measurement will
not be possible.

1-9
IM 701931-01E
1
2
• Athighfrequencies,commonmodenoisemayaffectmeasurementstakenon
the high voltage side of circuits. If this occurs, reduce the frequency range of the
waveform measuring instrument, or clamp onto the low-voltage side of the circuit,
as appropriate.
Power source Load
H
L
• DirectlyafterpoweringON,thedemagnetizingwaveformappearsintheoutput;
this is not a malfunction.
• Accuratemeasurementmaybeimpossibleinlocationssubjecttostrongexternal
magnetic fields such as transformers and high-current conductors, or in locations
subject to strong external electric fields such as radio transmission equipment.
701931 Current Probe

1-10 IM 701931-01E
Specifications
Product Specifications
Accuracy is guaranteed at 23 ± 3°C (73°F ± 5°F) after the power has been on
for 30 minutes.
Band width* DC to 2 MHz (–3 dB)
(Typical characteristics shown in the next page, Fig.1)
Rise Time* 175 ns or less
Maximum Continuous Input Range
500 A (Derating according to frequency shown in the next
page, Fig.2)
Maximum Peak Current Value
Non-Continuous 700 A
Output Voltage Rate* 0.01 V/A
Amplitude Accuracy* To 500 A: ±1%rdg. ±5 mV
500 A to 700 Apeak: ±2% rdg.
(DC, and 45 to 66 Hz)
Noise* Equivalent to 25 mArms or less (for 20 MHz band measuring
instrument)
Input Impedance (Typical characteristics shown in the next page, Fig.3)
Temperature Coefficient for Sensitivity*
±2% or less (within a range of 0 to 40°C or 32 to 104°F when
inputting 50 Hz, 500 A)
Propagation delay (typical)
57 ns
Maximum Rated Power 7.2 VAmax (at the maximum continuous input range)
Rated Supply Voltage ±12 V ±0.5 V
Operating Temperature and Humidity Range
0 to 40°C (32 to 104 °F), 80% RH or less (no condensation)
Storage Temperature and Humidity Range
–10 to 50°C (14 to 122°F), 80% RH or less (no condensation)
Location for Use Indoor, altitude up to 2000 m (6562 feet)
Effect of External Magnetic Fields
Equivalent to a maximum of 800 mA (in a DC or 60 Hz,
400 A/m magnetic field)
Diameter of Measurable Conductors
φ20mm
Guaranteed accuracy period
1 year (up to 10000 open and close operations)
Cable Lengths Sensor Cable: Approx. 2 m (78.7").
Power Supply Cable: Approx. 1 m (39.4")
External Dimensions Sensor:
Approx. 176 (W) × 69 (H) × 27 (D) mm.
Approx. 6.93" (W) × 2.72" (H) × 1.06" (D)
Terminator:
Approx. 27 (W) × 55 (H) × 18 (D) mm.
Approx.1.06" (W) × 2.17" (H) × 0.71" (D)
Mass Approx. 520 g.
Approx. 18.3 oz.
Accessories User’s manual, carrying case
* In conjunction with a waveform measuring instrument with an input
impedanceof1MΩ±1%

1-11
IM 701931-01E
1
2
Applicable Standards
Safety EN61010
EMC Emissions EN61326-1 Class B
EN55011 Class B, Group 1
EMC Regulatory Arrangement in Australia and New Zealand
EN 55011 Class B, Group 1
Immunity EN61326-1 Table 1 (Basic immunity requirement)
–30
–40
–50
–60
–70
–80
1 k100 10 k 100 k 1 M 10 M 100 M
Frequency [Hz]
Figure 1 Frequency Characteristics (Typical Characteristics)
Amplitude [dB, 0 dB=1 V]
10
100
1000
1 k10 100 10 k 100 k 1 M 10 M
Frequency [Hz]
Figure 2 Derating According to Frequency
Maximum input current [A]
1 m
10 m
100 m
10 k 100 k 1 M
Frequency [Hz]
Figure 3 Input Impedance (Typical Characteristics)
Input impedance [Ω]
701931 Current Probe

2-1
IM 701931-01E
1
2
Chapter 2 Malfunction? First, Investigate.
Corrective Action to be Taken in Case of an Abnormality
If maintenance service is required, or if the instrument still does not operate
properly even after proper corrective action has been taken, contact your
nearest YOKOGAWA dealer for repairs.
Symptom Possible Cause Corrective Action
Power is not turned ON. Turn ON the power.
Set the instrument to DC
coupling.
The sensor is not locked
(it is not hooked securely).
Lock the sensor.
Cannot adjust to the zero level
using the zero adjustment dial.
The sensor is magnetized. Demagnetize the sensor
before adjusting the zero level.
The amplitude is small across
all frequencies.
The input impedance of the
measurement instrument,
such as an oscilloscope, is
set to 50 Ω.
Set it to 1 MΩ.
Cannot make DC measurements
(or at low frequencies up to few
hundred Hertz) or the amplitude
is small in the given frequency
region.
The measurement instrument,
such as an oscilloscope, is
set to AC coupling.
Malfunction? First, Investigate.