Agilent 1147A 50 MHz Current Probe User`s Guide

Agilent 1147A 50 MHz Current Probe User`s Guide
Agilent N2893A
100 MHz Current
User’s Guide
Publication number N2893-97000
January 2011
For Safety information, Regulatory information, and
publishing information, see the pages at the end of
this book.
© Copyright Agilent Technologies 2011
All Rights Reserved.
N2893A 100 MHz Current Probe Introduction
The N2893A is a wide-band, DC to 100 MHz, active current probe. The probe
features low noise and low circuit insertion loss. It also features the AutoProbe
interface which makes current measurements as simple as those made with
active voltage probes.
The N2893A has two operating regions that provide a wide, flat frequency
response. In the DC to low frequency AC region, the probe operation is based
on the negative feedback of the amplifier system that includes the thin film
Hall element as a detector. In the high frequency region, the probe operates
as a current transformer.
The N2893A is ideal for acquiring high transient time signals such as those
found in Motor Controllers, in Switching Power Supplies, and in Current
Amplifiers driving inductive loads.
In order to use this product effectively and to ensure a long operational life,
read this User’s Guide carefully and retain it for future reference.
• Highly accurate current detection
• Easy current measurement
• Broadband frequency characteristics DC to 100 MHz
• Compact
• Permits measurement of low current levels
• Easy protect function at excessive input
Scope Compatibility
• 5000, 6000 (except 100 MHz models), and 7000 Series oscilloscopes with software
version 6.10 or higher
• 9000A Series with software version 3.0 or higher
• 90000 X-Series with the N5449A adapter
When the unit is delivered, check and make sure that it has not been damaged
in transit. If the unit is damaged, or fails to operate according to the
specifications, contact your dealer or Agilent representative.
Note on Safety 4
Safety Symbols 4
Safety Considerations 5
Description of Parts 7
Characteristics and Specifications 9
Measurement Characteristics 9
Power Supply Characteristics 9
Mechanical Characteristics 10
Environmental Characteristics 10
Plots 11
Preparations for Measurement 13
Demagnetization Procedure 14
Demagnetization and Zero Offset Procedure 14
Measurement Procedure 14
Service Strategy 18
To return the Probe to Agilent Technologies for Service
Calibration Testing Procedures 19
Test Equipment Required 19
Preliminary procedure 19
(1) AC Accuracy 20
Calibration Test Record 21
Note on Safety
Note on Safety
This equipment is designed according to IEC 61010-1 Safety Standards, and has been
tested for safety prior to shipment. Incorrect measurement procedures could result in
injury or death, as well as damage to the equipment. Please read this manual carefully
and be sure that you understand its contents before using the equipment. The
manufacturer disclaims all responsibility for any accident or injury except that resulting
due to defect in its product.
Safety Symbols
This User’s Guide provides information and warnings essential for operating this
equipment in a safe manner and for maintaining it in safe operating condition. Before
using this equipment, be sure to carefully read the following safety notes.
Caution refer to accompanying documents.
Indicates DC (Direct Current) or AC (Alternating Current).
The following symbols are used in this User’s Guide to indicate the relative importance
of cautions and warnings.
Indicates that incorrect operation presents extreme danger of
accident resulting in death or serious injury to the user.
Indicates that incorrect operation presents significant danger of
accident resulting in death or serious injury to the user.
Indicates that incorrect operation presents possibility of injury
to the user or damage to the equipment.
Denotes items of advice related to performance of the equipment
or to its correct operation.
Safety Considerations
Safety Considerations
Only trained service personnel who are aware of the hazard involveds (for example,
fire and electric shock) should perform maintenance on the instrument. When
maintenance can be performed without power applied, the power cord must be
disconnected from the instrument.
To ensure safe operation and to obtain maximum performance from the unit, observe
the cautions listed below.
• To avoid short circuits and accidents that could result in injury or death, use the
N2893A only with power lines carrying 300 V or less.
• When conductors being measured carry in excess of the safe voltage level (SELVE) and not more than 300 V, to prevent short circuits and electric shock while the
core section is open, make sure that conductors to be measured are insulated with
material conforming to (1) Overvoltage Category I, (2) Basic Insulation
Requirements for Working Voltages of 300 V, and (3) Pollution Degree 2. Never
use this sensor on bare conductors, the core and shield case are not insulated. If a
bare conductor is inevitable to be measured, make sure that the power to the wire
must be turned off, when opening the jaws of the probe to insert or remove the bare
wire so that 300V CAT I is always satisfied.
• Avoid damaging the cable insulation surfaces while taking measurements.
• This instrument is only made for use with the Infiniium. Do not plug the probe into
any interface other than the AutoProbe interface, of which Infiniium has a protective
earthing with double-insulation construction.
• Take the following precautions to ensure that the Infiniium does not form a bridge
between the probe and any hazardous live part.
1 Isolate the AutoProbe interface to which the probe is connected from other
AutoProbe interfaces using basic insulation conforming to the overvoltage
category, working voltage, and pollution degree requirements of the circuit
being tested.
2 If basic insulation requirements cannot be met between the AutoProbe interface
to which this unit is connected and other AutoProbe interfaces of the measuring
instrument, make sure that the voltage input to the AutoProbe interfaces does
not exceed the safe voltage level (SELV-E).
3 Read and observe all warnings and precautions relating to electrical safety for
the Infiniium.
• Refer to the following standards regarding the meanings of underlined terms.
• To prevent electric shock, do not allow the unit to become wet and do not use the
unit when your hands are wet.
• Do not subject the unit to vibrations or shocks during transport or handling. Be
especially careful to avoid dropping the unit.
Safety Considerations
Do not store the unit where it will be exposed to direct sunlight, high temperature,
high humidity, or condensation. If exposed to such conditions, the unit may be
damaged, the insulation may deteriorate, and the unit may no longer satisfy its
Before using the unit, inspect it and check the operation to make sure that the unit
was not damaged due to poor storage or transport conditions. If damage is found,
contact your dealer or Agilent representative.
This unit is not constructed to be waterproof or dustproof, so do not use it in a very
dusty environment or in one where it will get wet.
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.
Do not bend or pull the sensor cable and power supply cable in order to avoid
damaging the sensor cables.
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 benzine, alcohol, acetone, ether, ketones,
thinners, or gasoline. They may cause discoloration or damage.
To avoid scratching the surfaces of the Hall effect elements, keep the core section
of the sensor closed, except when clamping it around the conductor to be measured.
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.
Description of Parts
Description of Parts
Current direction indication
"UNLOCK" indication
4 3
Sensor cable
1 Opening lever
Operating lever for opening the sensor head. Always use this lever to open the sensor
2 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. Care should be exercised when handing
the sensor head.
3 Demagnetizing switch (DEMAG)
This demagnetizes the core if it has been magnetized by switching the power on and
off, or by an excessive input. Always carry out demagnetizing before measurement.
The demagnetizing process takes about one second. During demagnetizing, a
demagnetizing waveform is output.
4 Coarse adjustment trimmer
This adjustment should only be carried out if the probe offset is outside the range of
the zero adjustment.
Description of Parts
• The output of this unit is terminated internally. The high-impedance such as 1 M
input impedance will be automatically selected on the Infiniium, as the Terminator
is plugged into the AutoProbe interface. With an input impedance of 50 , accurate
measurement is not possible.
• The probe output sensitivity 0.1 V/A will be automatically selected, as the
Terminator is plugged into the AutoProbe interface. With an different output
sensitivity, accurate measurement is not possible.
Characteristics and Specifications
Characteristics and Specifications
Measurement Characteristics
See note 1 below.
Probe Bandwidth
Accuracy (Probe Only)*
DC to 100MHz (-3 dB)
±1% of reading ±1mV
(DC or 45Hz to 66Hz)
~ 7ns
Maximum continuous current
15A (DC + ACrms) continuous
(Refer to frequency derating curve, Fig. 2)
Maximum peak current
50A (for Pulse Widths ~ 10µs)
Probe sensitivity
~ 2.5mArms(with 20MHz Bandwidth limiting)
Insertion impedance
Refer to Fig. 3
Temperature coefficient
~ ±2% (0%C to 40%C)
Effect of external magnetic fields Equivalent to ~ 20mA (for a 400A/m magnetic
field, DC to 60Hz)
Maximum circuit voltage
300V Cat I (refer to safety considerations and
product compliances)
*This is a specification and is guaranteed at 23%C ±3%C (73%F ±5%F).
1. Requires 1MW termination. Valid for 23%C ±3%C (73%F ±5%F), at least 30 minutes after power
2. Rise time is calculated as: Tr = 0.35/Bandwidth.
Power Supply Characteristics
DC supply voltage requirements
Probe power consumption
±12Vdc ±1V
Increases with measured current.
3 VA when measuring 15 A
Characteristics and Specifications
Mechanical Characteristics
Maximum cable diameter
Sensor cable length
Power cable length
Accessories supplied
5 mm (0.2 inch)
1.5 m (59 inches)
1 m (39 inches)
175 mm x 18 mm x 40 mm
6.89 in. x 0.71 in. x 1.6 in.
Terminator: 28 mm x 81 mm x 24 mm
1.1 in. x 3.2 in. x 0.94 in
210 g (7.4 oz.)
storage case, calibration certificate
Environmental Characteristics
See note 3 below.
Operating temperature range
Storage temperature range
Maximum relative humidity
(operating or storage)
Maximum Altitude
0%C to 40%C (32%F to 104%F)
-10%C to 50%C (14%F to 122%F)
80% (no condensation)
10 to 55 Hz: 30 min/axis
10 octave/min
Amplitude 0.3 mm
55 Hz:
30 min/axis
Amplitude 0.3 mm
Acceleration 17.91 m/s2
2000 m
3. This probe is intended for indoor use only.
Frequency response of N2893A
Continuous maximum input rating of N2893A
Insert impedance of N2893A
Amplitude accuracy characteristic of N2893A
Measurement Procedure
Measurement Procedure
Preparations for Measurement
1 Power on the oscilloscope.
2 Connect the probe terminator to one of the scope channels.
When the probe is connected to a scope channel, the AutoProbe interface will recognize
the probe as an N2893A and will automatically make several settings on the channel
to which the probe is connected:
• This probe is NOT compatible with 50 only Infiniium oscilloscopes (e.g. the
90000A series oscilloscopes) unless there is an adapter such as with the 90000 XSeries.The input coupling is automatically selected to DC, as the terminator is
plugged into the AutoProbe interface.
Measurement Procedure
Demagnetization Procedure
Refer to the Description of Parts section of this manual when performing this procedure
1 Allow both the Infiniium oscilloscope and the probe to warm up for at least
30 minutes before making these adjustments.
2 Ensure that the channel offset is set to 0 V on the oscilloscope channel to which
the probe is connected.
3 Ensure that the probe sensor is NOT clamped around any conductors.
4 Slide the probe sensor Opening Lever into the Locked position.
5 Press the DEMAG button on the terminator.
A demagnetization waveform will be displayed for a short time on the channel to which
the probe is connected. Wait until this waveform is no longer displayed.
Demagnetization and Zero Offset Procedure
1 For InfiniiVision Oscilloscopes: Press the input channel button (1, 2, 3, or
4) on the front panel of the oscilloscope for the channel you are using and then
press the Probe softkey under the display. You will then see a softkey for
automatically setting the demagnetization and offset. Press this key. The
oscilloscope will then guide you through the process. 
For Infiniium Oscilloscopes: In the Infiniium application, go to Setup >
Probes and click the button in the GUI to automatically start the
demagnetization and zero offset process. The GUI will then guide you through
the procedure. 
Measurement Procedure
Ensure all safety warnings and precautions are followed.
1 Perform the Demagnetization and Zero Adjustment procedure above.
2 Clamp the sensor head around the conductor to be measured.
3 To obtain the best accuracy, ensure that:
a The current direction indicator on the sensor aligns with actual current direction in
the conductor.
b The sensor opening lever is in the Locked position
c The cable is centered in the sensor head.
Measurement Procedure
• The maximum continuous input range is based on heat that is internally generated
during measurement. Never input current in excess of this level. Exceeding the rated
level may result in damage to the probe.
• The maximum continuous input range varies according to the frequency of the
current being measured. See figure 2 in “Characteristics and 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 (unclamp 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.
• Even if the input current does not exceed the rated continuous maximum,
continuous input for an extended period of time may result in activation of the safety
circuit to prevent damage resulting from heating of the sensor.
• 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.
• When opening the sensor head of the probe, be sure to operate with the opening
lever. If an upper core is forced to open when the sensor head is locked, the openclose mechanism can be damaged.
Upper core
Lock state
Do not Press
• Do NOT measure current such that the total probe current consumption exceeds the
allowable AutoProbe interface current consumption. The excess current
consumption causes a temporary shutdown of the Infiniium power supply for safety.
Quit the measurement and cycle the power of the Infiniium, if the shutdown occurs.
The typical probe current consumption from the AutoProbe interface is shown in
figure 4.
Current consumption [mA]
Measurement Procedure
AC (f=50Hz)
Current to be measured [A]
Figure 4. Typical probe consumption
• 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, it is necessary to be aware that the
zero offset voltage will drift if the ambient temperature changes.
• Under certain circumstances, oscillation may occur if the probe is connected to the
AutoProbe interface while the Infiniium is on. This does not indicate a malfunction.
Oscillation can be stopped and operation restored to normal by opening and closing
the sensor head.
• At some frequencies, some sound may be produced by resonance, this has no effect
on measurements.
• Measurement accuracy is affected by the position of the conductor being measured
within the clamp aperture. The conductor should be in the center of the clamp
• Before making a measurement, press the opening lever until the "UNLOCK"
indication disappears and check that the sensor head is properly closed. If the sensor
head is not properly closed, accurate measurement will not be possible.
• 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.
• 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 shown in figure 5), as appropriate.
Measurement Procedure
Figure 5. Low-voltage side of the circuit
Service Strategy
Service Strategy
For calibration testing, return the N2893A probe to an Agilent Service Center. If the
probe is under warranty, normal warranty services apply. If the probe is not under
warranty, replacement costs will be applied.
To return the Probe to Agilent Technologies for Service
Call (877) 447-7278 for further details and the location of your nearest Agilent
Technologies Service Office or go to for contact information.
1 Write the following information on a tag and attach it to the probe.
• Name and address of the owner
• Probe model number
• Description of service required or failure indications
2 Retain all accessories.
3 Return the probe in its case or pack the probe in foam or other shock-
absorbing material and place it in a strong shipping container. You can
use the original shipping materials or order materials from an Agilent
Technologies Sales Office. If neither are available, place 3 to 4 inches of
shock-absorbing material around the instrument and place it in a box that does
not allow movement during shipping.
4 Seal the shipping container securely.
5 Mark the shipping container as FRAGILE. In all correspondence, refer to the
instrument by model number and full serial number.
Calibration Testing Procedures
Calibration Testing Procedures
These procedures are used to test the warranted specifications for the N2893A
Differential Probe. The recommended calibration test interval for the N2893A is once
a year or as required. Use the equipment listed in the “Test Equipment Required”
section to complete the Calibration Testing Procedure.
Test Equipment Required
Minimum Requirements
Recommende Used at
d test
Bandwidth 250 MHz
(1), (2), (3),
Amplitude accuracy: ~0.4 oscilloscope (4)
with 1M
Current loop wire 16 AWG, Convenient length 30 cm
AC current
AC 10 Arms, 50 Hz, sine Wavetek 9100 (1)
Amplitude accuracy: ~0.3
50 current loop
N2774-23801 (4)
Preliminary procedure
1 Turn on the oscilloscope and then connect the N2893A probe to the it. Turn
on the other equipment.
2 Wait 30 minutes to warm up the equipment.
Calibration Testing Procedures
(1) AC Accuracy
Press the DEMAG button on the Terminator.
Connect the wire to the current terminals of the AC current generator.
Clamp the wire with the N2893A and lock the sensor head.
Set the Infiniium setups as follows:
Averaging: 16
Time: 5 ms/div
Vertical axis: 5 A/div
Trigger level: 0 mV
Trigger slope: Rise
Measurement mode: Vrms (Voltage)
Measurement Area: Entire Display
RMS Type: AC
Other setups: APPROPRIATE
5 Set the Generator setups to AC 10 Arms, 50 Hz, and sine wave.
6 Generate the wave, measure the current and record it.
7 Remove the wire and the generator from the N2893A.
AC current generator
Infiniium with
1MΩ input
Current Probe
Current loop
Calibration Testing Procedures
Calibration Test Record
Agilent Technologies
N2893A DC to 100 MHz Current Probe
Recommended Test Interval: 1 year
Serial No.: ___________________
Certification Date: ______________
Tested By: ___________________
Certification Temperature: _______________________
Recommended Date of Next Certification: ___________
(1) AC Accuracy [Arms]
The AC Accuracy range is based on the Infiniium oscilloscope’s accuracy. Calculate
the minimum and the maximum limits corresponding to the accuracy of your Infiniium
Calibration Testing Procedures
This apparatus has been
designed and tested in accordance with IEC Publication
1010, Safety Requirements
for Measuring Apparatus, and
has been supplied in a safe
condition. This is a Safety
Class I instrument (provided
with terminal for protective
earthing). Before applying
power, verify that the correct
safety precautions are taken
(see the following warnings).
In addition, note the external
markings on the instrument
that are described under
"Safety Symbols."
• Before turning on the instrument, you must connect the
protective earth terminal of
the instrument to the protective conductor of the (mains)
power cord. The mains plug
shall only be inserted in a
socket outlet provided with a
protective earth contact. You
must not negate the protective action by using an extension cord (power cable)
without a protective conductor (grounding). Grounding
one conductor of a two-conductor outlet is not sufficient
• Only fuses with the required
rated current, voltage, and
specified type (normal blow,
time delay, etc.) should be
used. Do not use repaired
fuses or short-circuited fuseholders. To do so could cause
a shock or fire hazard.
• If you energize this instrument by an auto transformer
(for voltage reduction or
mains isolation), the common
terminal must be connected to
the earth terminal of the
power source.
• Whenever it is likely that the
ground protection is impaired,
you must make the instrument inoperative and secure it
against any unintended operation.
Agilent Technologies
P.O. Box 2197
1900 Garden of the Gods Road
Colorado Springs, CO 80901
• Service instructions are for
trained service personnel. To
avoid dangerous electric
shock, do not perform any
service unless qualified to do
so. Do not attempt internal
service or adjustment unless
another person, capable of
rendering first aid and resuscitation, is present.
• Do not install substitute
parts or perform any unauthorized modification to the
• Capacitors inside the instrument may retain a charge
even if the instrument is disconnected from its source of
• Do not operate the instrument in the presence of flammable gasses or fumes.
Operation of any electrical
instrument in such an environment constitutes a definite
safety hazard.
• Do not use the instrument in
a manner not specified by the
To clean the instrument
If the instrument requires
cleaning: (1) Remove power
from the instrument. (2) Clean
the external surfaces of the
instrument with a soft cloth
dampened with a mixture of
mild detergent and water. (3)
Make sure that the instrument
is completely dry before
reconnecting it to a power
Safety Symbols
Instruction manual symbol:
the product is marked with
this symbol when it is necessary for you to refer to the
instruction manual in order to
protect against damage to the
Hazardous voltage symbol.
Earth terminal symbol: Used
to indicate a circuit common
connected to grounded chassis.
and any information
contained herein, including but not limited to the
implied warranties of
© Agilent Technologies, Inc.
merchantability and fit2011
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tronic storage and retrieval or or for incidental or contranslation into a foreign lansequential damages in
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nishing, use, or perforfrom Agilent Technologies,
mance of this document
Inc. as governed by United
States and international copy- or of any information
right laws.
contained herein. Should
Agilent and the user
Manual Part Number
have a separate written
N2893-97000, January 2011
agreement with warranty terms covering the
Print History
material in this docuN2893-97000, January 2011
ment that conflict with
Agilent Technologies, Inc.
these terms, the war1900 Garden of the Gods
ranty terms in the sepaRoad 
Colorado Springs, CO 80907 rate agreement shall
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performance of a U.S. Government prime contract or
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without notice, in future
editions. Further, to the
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A WARNING notice
denotes a hazard. It
calls attention to an
operating procedure,
practice, or the like
that, if not correctly
performed or adhered
to, could result in
personal injury or
death. Do not proceed
beyond a WARNING
notice until the
indicated conditions
are fully understood
and met.
A CAUTION notice
denotes a hazard. It
calls attention to an
operating procedure,
practice, or the like
that, if not correctly
performed or adhered
to, could result in
damage to the product
or loss of important
data. Do not proceed
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Agilent Technologies, Inc. 2011
First edition, January 2011
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