The servicing instructions are for use by qualified
personnel only. To avoid personal injury, do not
perform any servicing unless you are qualified to
do so. Refer to all safety summaries prior to
performing service.
Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes
that in all previously published material. Specifications and price change privileges reserved.
Tektronix, Inc., P.O. Box 500, Beaverton, OR 97077
TEKTRONIX and TEK are registered tradem arks of Tektronix, Inc.
WARRANTY
Tektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship
for a period of one (1) year from the date of shipment. If a product proves defective during this warranty period, Tektronix,
at its option, either will repair the defective product without charge for parts and labor, or will provide a replacement in
exchange for the defective product.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the
warranty period and make suitable arrangements for the performance of service. Customer shall be responsible for
packaging and shipping the defective product to the service center designated by Tektronix, with shipping charges prepaid.
Tektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the
Tektronix service center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and a ny
other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate
maintenance and care. Tektronix shall not be obligated to furnish service under this warranty a) to repair damage resulting
from attempts by personnel other than Tektronix representative s to install, re pair or service the product; b) to repair
damage resulting from improper use or connection to incompatible equipment; c) to repair any damage or malfunction
caused by the use of non-Tektronix supplies; or d) to service a product that has been modified or integrated with other
products when the effect of such modification or integration increases the time or difficulty of servicing the product.
THIS W ARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER W ARRANTIES, EXPRESS OR
IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY TO
REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO
THE CUSTOMER FOR BREACH OF THIS WARRANTY. TEKTRONIX AND ITS VENDORS WILL NOT BE
LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE
OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH
DAMAGES.
Service Assurance
If you have not already purchased Service Assurance for this product, you may do so at any time during the product’s
warranty period. Service Assurance provides Repair Protection and Calibration Services to meet your needs.
Repair Protection extends priority repair services beyond the product’s warranty period; you may purchase up to three
years of Repair Protection.
Calibration Services provide annual calibration of your product, standards compliance and required audit documentati on,
recall assurance, and reminder notification of scheduled calibration. Coverage begins upon registration; you may purchase
up to five years of Calibration Services.
Service Assurance Advantages
H Priced well below the cost of a single repair or calibration
H Avoid delays for service by eliminating the need for separate purchase authorizations from your company
H Eliminates unexpected service expenses
For Information and Ordering
For more information or to order Service Assurance, contact your Tektronix re p resentative and provide the information
below. Service Assurance may not be available in locations outside the United States of America.
NameVISA or Master Card number and expiration
Companydate or purchase order number
AddressRepair Protection (1,2, or 3 years)
City, State, Postal codeCalibration Services (1,2,3,4, or 5 years)
CountryInstrument model and serial number
PhoneInstrument purchase date
Table of Contents
General Safety Summaryv...................................
Table 5: Certifications and compliances10.......................
Table 6: Required test equipment12............................
Table 7: Equipment settings for bandwidth14....................
Table 8: Equipment settings for rise time17.....................
T able 9: Equipment settings for DC gain accuracy20..............
Table 10: DC gain accuracy test for A631221....................
Table 11: DC gain accuracy test work sheet for A631223...........
Table 12: Required test equipment24...........................
Table 13: AM503B/AM 5030 settings for DC offset adjustment25...
Table 14: AM 503B/AM 5030 error codes requiring
DC offset adjustment26...................................
Table 15: AM503A settings for DC offset adjustment27............
Table 16: AM503A error codes requiring DC offset adjustment28...
Table 17: AM 503 settings for DC offset adjustment29.............
A6312 Instructions
iii
Table of Contents
iv
A6312 Instructions
General Safety Summary
Review the following safety precautions to avoid injury and prevent damage to
this product or any products connected to it.
Only qualified personnel should perform service procedures.
Injury Precautions
Product Damage
Precautions
Avoid Electric Overload. To avoid electric shock or fire hazard, do not apply a
voltage to a terminal that is outside the range specified for that terminal.
Avoid Electric Shock. To avoid injury or loss of life, do not connect or disconnect
probes or test leads while they are connected to a voltage source.
Ground the Product. This product is indirectly grounded through the grounding
conductor of the mainframe power cord. To avoid electric shock, the grounding
conductor must be connected to earth ground. Before making connections to the
input or output terminals of the product, ensure that the product is properly
grounded.
Do Not Operate in Wet/Damp Conditions. To avoid electric shock, do not operate
this product in wet or damp conditions.
Do Not Operate in an Explosive Atmosphere. To avoid injury or fire hazard, do not
operate this product in an explosive atmosphere.
Do Not Operate With Suspected Failures. If you suspect there is damage to this
product, have it inspected by qualified service personnel.
Do Not Immerse in Liquids. Clean the probe using only a damp cloth. R efer to
cleaning instructions.
A6312 Instructions
v
General Safety Summary
Symbols and Terms
Terms in this Manual. These terms may appear in this manual:
WARNING. Warning statements identify conditions or practices that could result
in injury or loss of life.
CAUTION. Caution statements identify conditions or practices that could result in
damage to this product or other property.
Terms on the Product. These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you read the
marking.
WARNING indicates an injury hazard not immediately accessible as you read the
marking.
CAUTION indicates a hazard to property including the product.
Symbols on the Product. The following symbols may appear on the product:
Certifications and
Compliances
CAUTION
Refer to Manual
Breakable.
Do not drop.
WARNING
High Voltage
Use only on an
insulated wire.
Double
Insulated
Protective Ground
(Earth) Terminal
Do not connect to or
remove from an
uninsulated conductor that
is HAZARDOUS LIVE.
Refer to the specifications section for a listing of certifications and compliances
that apply to this product.
vi
A6312 Instructions
Preface
This instruction manual supports the operation and maintenance of the A6312
Current Probe with any of the AM503 series current probe amplifiers.
You can find additional documentation supporting the operation and maintenance
of the AM 503 series amplifiers in the following manuals:
HAM503 Instruction Manual (070-2052-XX)
HAM503S (AM503A) User Manual (070-8170-XX)
HAM503S (AM503A) Service Manual (070-8174-XX)
HAM503B & AM5030 Instruction Manual (070-8766-XX)
A6312 Instructions
vii
Preface
Contacting Tektronix
Phone1-800-833-9200*
AddressTektronix, Inc.
Department or name (if known)
14200 SW Karl Braun Drive
P.O. Box 500
Beaverton, OR 97077
USA
Web sitewww.tektronix.com
Sales support1-800-833-9200, select option 1*
Service support1-800-833-9200, select option 2*
Technical supportEmail: techsupport@tektronix.com
1-800-833-9200, select option 3*
6:00 a.m. -- 5:00 p.m. Pacific time
*This phone number is toll free in North America. After office hours, pl ease leave a
voice mail message.
Outside North America, contact a Tektronix sales office or distributor; see the
Tektronix web site for a list of offices.
viii
A6312 Instructions
Getting Started
Probe Installation
The A6312 is a DC to 100 MHz current probe designed for use with the AM503
series current probe amplifiers. With the AM503A amplifier, you can measure
frequencies up to 80 MHz. With the AM503, AM503B, and AM5030 amplifiers,
you can measure frequencies up to 100 MHz. The A6312 current probe can
measure currents to 20 A (DC + peak AC), and up to 50 A peak current (while
not exceeding the amp-second rating).
This section explains how to install and operate the A6312 current probe.
To connect the current probe to the amplifier input connector, align the tab of the
probe connector with the slot in the amplifier input connector as shown in
Figure 1(a). Align the dot on the probe connector with the groove opening of the
input connector as shown in Figure 1(b). Push the probe connector in while
twisting the barrel clockwise to lock the connector.
CAUTION. Handle the current probe with care. Do not drop the probe or subject
it to impact, or the core may crack. Do not connect or disconnect the current
probe while the probe is clamped around a live conductor or while the amplifier
is powered on, or the probe may suffer electrical damage.
A6312 Instructions
1
Getting Started
Amplifier
Push connector in
and twist to lock
Current probe connector
Tab
Slot
(a) Align the tab with the connector slot
Amplifier
Figure 1: Connecting a current probe to the current probe amplifier
Operating the Current Probe Slide
The current probe has a slide mechanism that opens and closes the probe jaw.
This allows you to clamp the probe around a conductor under test. The slide
must be locked to accurately measure current or to degauss the probe. If a probe
is unlocked, the PROBE OPEN indicator on the amplifier lights.
WARNING. When the probe slides are open, the exposed ferrite core pieces are
not insulated. To avoid injury or equipment damage, remove power from an
uninsulated wire before clamping the current probe around it. Also, never
disconnect the probe from the amplifier when the probe is connected to a live
conductor.
Current probe
connector
Groove
(b) Insert the connector into the amplifier
Alignment dot
2
A6312 Instructions
Getting Started
Figure 2 illustrates the slide operation of the probe. To open the probe, pull the
slide back until the jaw is open. To lock the probe, push the slide forward until
the detent snaps into place.
Probe openProbe locked
Figure 2: Operating the probe slide
Degaussing and Autobalancing the Current Probe
Degaussing the probe removes any residual magnetization from the probe core.
Such residual magnetization can induce measurement error. Autobalancing
removes unwanted DC offsets in the amplifier circuitry.
Failure to degauss the probe is a leading cause of measurement errors. To
maintain measurement accuracy, degauss your probe in each of these cases:
HAfter turning on the amplifier and allowing a 20-minute warm-up period
HBefore connecting the probe to a conductor, or changing conductors under
test
HWhenever an overload condition occurs
HWhenever the probe is subjected to a strong external magnetic field
HPeriodically during normal use
Degauss and autobalance the current probe as follows
1. Verify that the current probe is connected to the amplifier.
2. Remove the current probe from the conductor under test.
A6312 Instructions
3. Lock the probe slide closed (see Figure 2).
4. Press the amplifier PROBE DEGAUSS AUTOBALANCE button.
3
Getting Started
NOTE. The degauss procedure will fail if the amplifier is not properly connected
toa50Ω termination impedance.
After you have completed the oscilloscope adjustments and the degauss/autobalance procedure, your system is ready to measure current.
Maximum Current Limits
Current probes have three maximum current ratings: continuous, pulsed, and
Ampere-second product. Exceeding any of these ratings can saturate the probe
core and cause measurement errors. The section titled Specifications on page 7
lists the maximum current ratings of the probe.
HMaximum Continuous Current refers to the maximum current that can be
continuously measured at DC or at a specified AC frequency. The maximum
continuous current value is derated with frequency; as the frequency
increases, the maximum continuous current rating decreases.
Procedure A
HMaximum Pulsed Current refers to the maximum peak value of pulsed
current the probe can accurately measure, regardless of how short (within
bandwidth limitations) the pulse duration.
HAmpere-Second Product defines the maximum width of pulsed current that
you can measure when the pulse amplitude is between the maximum
continuous and maximum pulsed current specifications. The maximum
continuous specification itself varies by frequency.
NOTE. Always degauss the probe after measuring a current that exceeds the
maximum continuous current, maximum pulsed current, or Ampere-second
product rating of the probe. Exceeding these ratings can magnetize the probe
and cause measurement errors.
To determine if your measurement exceeds the Ampere-second product, perform
either Procedure A or Procedure B:
To determine the maximum allowable pulse width, measure the peak current of
the pulse (see Figure 3a). Divide the Ampere-second (or Ampere-microsecond)
specification of your probe by the measured peak current of the pulse. The
quotient is the maximum allowable pulse width; the pulse width at the 50% point
of the measured signal must be less than this value.
For example, the A6312 current probe has a maximum Ampere-second product
of 100 A⋅s. If a pulse measured with an A6312 has a peak current of 40 A, the
maximum allowable pulse width would be 100 A⋅s divided by 40 A, or 2.5 s.
4
A6312 Instructions
Getting Started
I
max
p
Pulse width
at 50%
50%
I
max
c
0A
(a) Maximum allowable pulse width(b) Maximum allowable pulse amplitude
Figure 3: Applying the amp-second product rule
Do not exceed
Maximum
pulsed
current
Pulse width
at 50%
50%
Maximum
continuous
current
A6312 Instructions
5
Getting Started
Procedure B
To determine the maximum allowable pulse amplitude, measure the pulse width
at the 50% points (see Figure 3b). Divide the Ampere-second (or Amperemicrosecond) specification of your probe by the pulse width. The quotient is the
maximum allowable current; the peak amplitude of the measured pulse must be
less than this value.
For example, the A6312 current probe has a maximum Ampere-second product
of 100 A⋅s. If a pulse measured with an A6312 probe has a width of 3 s, the
maximum allowable peak current would be 100 A⋅s divided by 3 s, or 33.3 A.
6
A6312 Instructions
Specifications
This section lists the specifications, characteristics, certifications, and compliances for the A6312 current probe.
Warranted specifications, Table 1, are guaranteed performance specifications
unless specifically designated as typical or nominal.
Table 1: Warranted A6312 specifications
Installed amplifier
Parameter
AM503
AM503AAM503B/AM5030
BandwidthDC to 100 MHz, --3 dBDC to 80 MHz, --3 dBDC to 100 MHz, --3 dB
P-P
1
1
≤4.4 ns≤3.5 ns
7%
P-P
7%
P-P
Rise time, 10% to 90%≤3.5 ns
Aberrations (typical)7%
DC gain accuracy≤3%≤3%≤3% (<1.5% typical)
System noise (typical)≤250 A
1
You can optimize the pulse response by adjusting R364 (HF COMP) located inside the AM503 amplifier. Refer to the
RMS
3
≤250 A
RMS
3
≤250 A
RMS
3
AM503 Instruction Manual (070-2052-XX) for instructions on how to access this adjustment.
2
On the AM503B and AM5030, the DC gain accuracy is correctable to < 0.2% when using the AM503B and AM5030 probe
trim procedure described on page 22.
3
The bandwidth of the measurement instrument must be ≤ 500 MHz.
Mechanical, electrical, and environmental characteristics for the A6312 current
probe are listed in Tables 2 through 4 and Figures 4 through 7.
Table 2: Electrical characteristics
Frequency derating2 A at 20 MHz
Maximum bare wire working voltage300 V
Maximum continuous current20 A (DC + peak AC)
RMS
2
Maximum pulsed current50A
Amp⋅second product1 ¢ 10-4A⋅s (100 A⋅s)
Insertion impedance0.1 Ω at 1 MHz
0.5 Ω at 50 MHz
1 Ω at 100 MHz
A6312 Instructions
7
Specifications
50
Maximum peak pulse (≤50 A)
40
30
20
Amperes (peak)
10
Allowable pulse width (microseconds)
Figure 4: A6312 specified operating area
Amp-second product limit = 100 A ⋅ s
Maximum continuous input (≤20 A)
Any width
54321
200
100
50
10
Maximum input current (amperes peak)
1
1kHz
10 kHz
Frequency
Figure 5: A6312 frequency derating curve for maximum input current
100 MHz10 MHz1MHz100 kHz
8
A6312 Instructions
1.0
Specifications
0.5
0.2
0.1
.05
Typical impedance
Impedance deviation
Insertion impedance (ohms)
.02
.01
0.1
0.2
Frequency (MHz)
Figure 6: A6312 insertion impedance curve
105210.5
100
5020
Table 3: Mechanical characteristics
Probe dimensionsLength:20 cm (7.77 inches)
Width:1.6 cm (0.625 inches)
Height:3.2 cm (1.25 inches)
Cable length2 m (6.6 feet)
Weight255 g (0.56 lbs)
Maximum Wire Size
11.9 mm
(0.470 in)
18.9 mm
(0.745 in)
3.8 mm (0.15 in)
Figure 7: A6312 Probe jaw dimensions (nominal)
A6312 Instructions
9
Specifications
c
ala
Und
Labora
ifiedtoStand
ardIE
C
P
arti
cul
a
Table 4: Environmental characteristics
Operating temperature0° Cto50° C
Storage temperature-- 4 0 ° Cto75° C
Humidity
Nonoperating
Operating
TransportationQualifies under National Safe Transit Procedure 1A, category II, 36 in. drop
Mechanical shock500 g. Half sine. Three shocks on three axes of the probe for 1 ms duration. Total of 9 shocks
Vibration0.025 in. pk--pk displacement. 10 -- 50 Hz in 1min. cycles. Hold 9 min. at any major
Random vibration
Operating
30° Cto60° Cat90to95%RH
30° Cto50° Cat90to95%RH
resonance, or if none, at 55 Hz. Total time, 54 min
0.31 g
Tektronix Std. 062--2858--00, Rev. B, Class 3
, 5 to 500 Hz, 10 minutes on each axis
RMS
Table 5 lists the product certifications and compliances.
Table 5: Certifications and compliances
EC Declaration of ConformityMeets intent of Low Voltage Directive 73/23/EEC for Product Safety. Compliance was
demonstrated to the following specification as listed in the Official Journal of the European
Communities:
Low Voltage Directive 73/23/EEC as amended by 93/68/EEC:
EN 61010-1Safety requirements for elect ric al equipment for measurement,
control, and laboratory use
EN 61010-2-032:1994Particular requirements for hand-held current clamps for
electrical measurement and test
CertificationsUnderwriters Laboratories certified to Standard UL3111-1 and CSA/CAN C22.2 No. 1010.1 for
Electri
nd ElectronicMeasuringand Testing Equipment.
erwriters
hand-held current clamps for electrical measurement and test.
Overvoltage categoryCategory:Examples of Products in this Category:
Do not operate in environments where conductive pollutants may be present.
10
toriescert
Local-level mains, appliances, portable equipment
Signal levels in special equipment or parts of equipment,
telecommunications, electronics
1010-2-032,
r requirementsfor
A6312 Instructions
Performance Verification
The Performance Verification tests allow you to demonstrate that the A6312
current probe meets its specified levels of performance.
Tolerances that are specified in these procedures apply to the AM503 series
current probe amplifiers and the A6312 current probe and do not include test
equipment error.
The recommended calibration interval is one year.
Test Procedure Conditions
These procedures are valid only under the following conditions:
HThe system has been calibrated at an ambient temperature of 23_ ± 5_ C.
HThe system is operating in an environment whose limits are described in
Table 4 on page 10.
HThe system, including probe, has had a warm-up period of at least
20 minutes.
Equipment Preparation
HThe probe degauss/autobalance routine has been performed after the
20-minute warm-up period.
Before starting these procedures, read completely through each procedure to
ensure proper completion.
Before performing the verification tests, install all plug-in units into the power
module and turn the power on. Turn any remaining equipment on and allow the
entire system, including the attached probe, to warm up for a minimum of 20
minutes.
A6312 Instructions
11
Performance Verification
NOTE. Before performing any verification procedure, properly degauss the
probe. Remove the probe from any current-carrying conductor, lock the probe,
and press the amplifier PROBE DEGAUSS AUTOBALANCE button. The
degauss/autobalance routine is complete when the indicator light turns off.
The amplifier front panel displays an error code 266 during the degauss/
autobalance routine if the amplifier is not properly terminated into 50 Ω. Verify
that the oscilloscope input is 50 Ω and set to DC coupling. Use a 50 Ω
feedthrough termination, attached at the oscilloscope input, if necessary.
Required Test Equipment
To perform the acceptance tests in this section, you will need the test equipment
listed in Table 6. The test equipment must meet or exceed the specifications
listed. The test procedures may need to be modified if the recommended
equipment is not used.
Table 6: Required test equipment
Recommended
QtyItemDescription
1Oscilloscope500 MHz bandwidthTDS520B
1Current probe
amplifier
1Leveled sine wave
generator
1Calibration generator1 MHz square wave, rise time <1 ns,
1Digital multimeter0.25% 31/2digit resolution at 50 mVDM2510/G or
1Current source0.3% accuracy, 0 to ±2AFluke 5700A or
1Current loop20 turns 27 AWG coated wireRefer to page 19.
1Termination50 Ω, ±0.1%, 0.5 W011-0129-00
AM503 seriesSelect the amplifier
3 MHz to 100 MHz, ±4% flatnessWavetek 9100 with
1V
into 50 Ω
p-p
Equipment
as noted on page 13.
Option 250 or
SG503 equivalent.
Wavetek 9100 with
Option 250 or
PG506A equivalent.
Fluke 850x/884x
Wavetek 9100 with
Option 250
12
1BNC cable50 Ω, 1.05 m (42 in) long012-0057-01
1BNC-to-Dual
Banana Adapter
103-0090-00
A6312 Instructions
Performance Verification
Performance and interchangeability of the A6312 probe depends upon the type of
amplifier you select to verify the probe. When selecting one of the AM503 series
amplifiers, please note the following:
HIf you select the AM503B or AM5030 amplifier, the procedures verify the
A6312 probe to 100 MHz and the probe is then interchangeable between
either amplifier.
HIf you select the AM503 amplifier, you must verify the probe and AM503 as
a system. The procedures verify the A6312 probe to 100 MHz and the probe
is not interchangeable with any other amplifier or system.
HIf you select the AM503A amplifier, you must verify the probe and
AM503A as a system. The procedures verify the A6312 probe to 80 MHz
and the probe is not interchangeable with any other amplifier or system.
A6312 Instructions
13
Performance Verification
Bandwidth
This procedure tests the bandwidth of the A6312 current probe. In this test you
measure a signal at a relatively low frequency and again at the rated bandwidth
of the probe. The two measurements are compared to verify that the signal
amplitude does not fall below --3 dB at the probe bandwidth. Refer to Figure 8
when making equipment connections.
Amplifier in TM
Test oscilloscope
50 Ω oscilloscope input (or add 50 Ω
termination here if oscilloscope has
only high-impedance input).
Series Power
Module
Leveled
sine wave
generator
Current probe
Output
Calibration
fixture
Equipment Connections
Equipment Settings
Figure 8: Bandwidth test setup for the A6312 current probe
1. Using a 50 Ω BNC cable, connect the amplifier output to a 50 Ω oscillo-
scope input. If the input impedance of your oscilloscope is 1 MΩ, connect a
50 Ω feedthrough termination at the oscilloscope input. Do not connect the
termination at the amplifier output.
2. Connect the current probe to the amplifier input.
3. Connect the current loop calibration fixture to the output of the leveled sine
wave generator.
Make or verify the equipment settings in Table 7.
Table 7: Equipment settings for bandwidth
Oscilloscope
Vertical input impedance50 Ω
Vertical gain10 mV/division
Time base200 ns/division
Record length500
CouplingDC
Offset0 V (mid-scale)
14
A6312 Instructions
Table 7: Equipment settings for bandwidth (Cont.)
Oscilloscope
Trigger typeEdge
Trigger modeAuto
Trigger position50%
Acquisition modeAverage
Number of waveforms to average8
Measurement typePeak-to-peak
1. Do not clamp the current probe around any conductor, but make sure the
jaws are locked shut.
2. Press the amplifier PROBE DEGAUSS AUTOBALANCE button. Wait for
the degauss/autobalance routine to complete before proceeding. The routine
is complete when the indicator light turns off.
3. Clamp the current probe around the calibration fixture.
4. Adjust the signal generator output so that the amplifier output is approxi-
mately 60 mV
, or six graticule divisions on the oscilloscope.
p-p
5. Using the peak-peak measurement capability of the oscilloscope, measure
and record the peak-peak reading as M
.
1
6. Set the oscilloscope time base to 5 ns/division. Increase the signal generator
frequency to the warranted bandwidth. Refer to Table 1 on page 7.
7. Using the peak-peak measurement capability of the oscilloscope, measure
and record the peak-peak reading as M
.
2
A6312 Instructions
15
Performance Verification
8. The probe meets the bandwidth specification if the ratio of the signal
amplitude at the warranted bandwidth is at least 70.7% of the signal
amplitude at 3 MHz. Using the following calculation, verify probe bandwidth:
M
2
Ꮛ
Ꮠ
> 0.707
M
1
NOTE. The impedance of the calibration fixture used in this test changes between
3 MHz and 100 MHz. Typically the impedance changes from 50 Ω at 3 MHz to
59 Ω at 100 MHz. Thus you can substitute the following equation to make this
test more accurate:
At 100 MHz,
M
(
1.18
For the AM503A at 80 MHz,
2
)
Ꮛ
Ꮠ
> 0.707
M
1
Rise Time
M
(
1.12
9. Verify that the bandwidth is greater than the warranted specification. Refer to
This procedure measures the rise time of the A6312 current probe. In this test
you directly measure the rise time of a step input. Refer to Figure 9 when
making equipment connections.
2
)
Ꮛ
Ꮠ
> 0.707
M
1
Table 1 on page 7.
16
A6312 Instructions
Performance Verification
Equipment Connections
Test oscilloscope
50 Ω input
Amplifier in TM
Series Power
Module
Current probe
Calibration
generator
Fast rise
output
Calibration
fixture
Figure 9: Rise time test setup for A6312
1. Using a 50 Ω BNC cable, connect the amplifier output to a 50 Ω oscillo-
scope input. If the input impedance of your oscilloscope is 1 MΩ, connect a
50 Ω feedthrough termination at the oscilloscope input. Do not connect the
termination at the amplifier output.
2. Connect the current probe to the amplifier input.
Equipment Settings
3. Connect the current loop calibration fixture to the calibration generator 50 Ω
fast rise output.
NOTE. If your oscilloscope cannot trigger on the pulse, use another BNC cable
to connect the trigger output of the pulse generator to the trigger input of the
oscilloscope. Configure the oscilloscope for an external trigger.
Make or verify the equipment settings in Table 8:
Table 8: Equipment settings for rise time
Oscilloscope
Vertical input impedance50 Ω
Vertical gain10 mV/division
Time base2 ns/division
Record length500
CouplingDC
Offset0 V (mid-scale)
Trigger typeEdge
Trigger modeAuto
A6312 Instructions
17
Performance Verification
Table 8: Equipment settings for rise time (Cont.)
Oscilloscope
Trigger position50%
Acquisition modeAverage
Number of waveforms to average32
Measurement typeRise time
1. Do not clamp the current probe around any conductor, but make sure the
jaws are locked shut.
2. Press the amplifier PROBE DEGAUSS AUTOBALANCE button. Wait for
the degauss/autobalance routine to complete before proceeding. The routine
is complete when the indicator light turns off.
3. Clamp the current probe around the calibration fixture. Verify that the
arrow-shaped indicator on the probe points away from the pulse source.
4. Using the measurement capability of the oscilloscope, measure the rise time
of the displayed pulse from 10% to 90% amplitude.
5. Calculate the rise time of the probe (t
trprobe =trmeasured2− trsystem
Ꭹ
probe) using the formula below:
r
2
The measured rise time (trmeasured) is the value calculated in step 4.
The system rise time (t
system) is the rise time of the displayed signal when
r
output of the pulse generator is connected directly to the oscilloscope input.
(The current probe and amplifier are excluded.)
18
A6312 Instructions
DC Gain Accuracy
Performance Verification
6. Verify that the probe rise time is less than the warranted specification. Refer
to Table 1 on page 7.
NOTE. When using the A6312 on an AM503, you can optimize the pulse response
by adjusting R364 (HF COMP) located inside the AM503 amplifier. Refer to the
AM503 Instruction Manual (070-2052-XX) for instructions on how to access this
adjustment. This information is in the service section of the manual and the
adjustment should be performed by qualified service personnel only.
This procedure tests the DC gain accuracy of the A6312 current probe. In this
test you compare the voltage output of the amplifier to a reference input.
Current Loop for DC Gain
Accuracy Check
Equipment Connections
You will need to construct a simple current loop in order to complete the DC
gain accuracy tests.
WARNING. Magnetic fields are produced that may cause a malfunction in heart
pacemakers, or damage to sensitive equipment.
Construct the loop using a cylindrical form approximately 3 inches in diameter,
wind exactly 20 turns of #27 coated wire.
NOTE. Ensure that the current loop has exactly 20 turns. A significant error will
result for each turn variance from 20 turns.
1. Using a BNC cable, connect the amplifier output to the 50 Ω feedthrough
termination. Attach the termination to a BNC-to-dual banana adapter. Taking
care to observe and maintain polarity, insert the dual banana adapter into the
digital multimeter DC voltage input.
2. Connect the current loop to the current source as shown in Figure 10.
1. Do not clamp the current probe around any conductor, but make sure the
jaws are locked shut.
2. Press the amplifier PROBE DEGAUSS AUTOBALANCE button. Wait for
the degauss/autobalance routine to complete before proceeding. The routine
is complete when the indicator light turns off.
3. Clamp the current probe around the 20 turn current loop, as shown in
Figure 10. Verify that the arrow-shaped indicator on the probe points away
from the current source.
A6312 Instructions
Performance Verification
4. For each of the amplifier current/division settings in Table 10, perform the
following steps:
a. Set the Amplifier to the desired current/division setting from Table 10.
b. Set the current source to the correct positive test current using Table 10.
c.Turn on the current source.
d. Record the exact measurement of the digital multimeter as M
. (You can
1
copy Table 11 on page 23 to record the results of your measurements.)
e.Set the current source for the correct negative test current using Table 10.
Table 10: DC gain accuracy test for A6312
Turns of current
loop passing
through probe
201mA±250 A10 mA
202mA±500 A20 mA
205mA±1.25 mA50 mA
2010 mA±2.5 mA100 mA
2020 mA±5mA200 mA
2050 mA±12.5 mA500 mA
20100 mA±25 mA1A
20200 mA±50 mA2A
20500 mA±125 mA5A
201A±250 mA10 A
Current probe
amplifier
current/division
Current source
output
Test current
I
t
A6312 Instructions
202A±500 mA20 A
205A±1A40 A
f.Record the digital multimeter reading as M2.
g. Calculate the measured current (I
M
Im=
1–M2
× (currentdivision)
0.01
) using the following formula:
m
21
Performance Verification
For example, you might have obtained values of 50 mV for M
48 mV for M
you can compute I
(50.0x10
Im=
. If you are using an amplifier setting of 10 mA/division,
2
as:
m
–3
) – (–48x10–3)
0.01
× (10x10–3) = 98 mA
h. Verify that the measured current (Im) is within ±3% of the test current (It)
by computing %Error as follows:
%Error =
m
t
× 100
I
t
I
− I
For example, using a test current Itof 100 mA and a measured current I
of 98 mA, the %Error would be:
%Error =
98 – 100
100
× 100 = –2%
Probe Trim Adjust for Gain Accuracy (AM503B and AM5030 Only)
After the PROBE DEGAUSS AUTOBALANCE routine has been run, the probe
and amplifier system will meet all published specifications; however, if you want
to improve the tolerance of the system gain accuracy, or to intentionally offset
the gain accuracy to make up for total system errors, the probe trim adjust
routine may be performed.
and
1
m
Probe trim adjust is a multiplicative factor that you can use to adjust the gain of
the current amplifier system. You can set this multiplier in increments of 0.001
from 0.750 through 1.250. Probe trim adjust is used for an optional calibration of
some current probes. If you are not performing such an adjustment, leave probe
trim adjust to the factory-default of unity gain (1.000).
To set probe trim adjust, press and hold the 20MHz BW LIMIT button while
pressing and releasing the COUPLING button. Use the
andbuttons to
adjust the setting that is displayed in the CURRENT/DIVISION display. When
finished, press either the 20MHz BW LIMIT or COUPLING button to restore
normal operation.
The display shows the last three significant digits of the display adjust setting;
the leading 0. or 1. are omitted. If the first digit displayed is 7, 8, or 9, then the
leading digit must be 0. If the first digit displayed is 0, 1, or 2, then the leading
digit must be 1.
22
A6312 Instructions
Table 11: DC gain accuracy test work sheet for A6312
Performance Verification
Turns of current
loop passing
through probe
Current probe
amplifier
current/division
Current source
output
Test current
I
t
201mA±250 A10 mA
202mA±500 A20 mA
205mA±1.25 mA50 mA
2010 mA±2.5 mA100 mA
2020 mA±5mA200 mA
2050 mA±12.5 mA500 mA
20100 mA±25 mA1A
20200 mA±50 mA2A
20500 mA±125 mA5A
201A±250 mA10 A
202A±500 mA20 A
205A±1A40 A
1
Im=
2
%Error =
M
– M
1
2
× (currentdivision)
0.01
I
− I
m
I
t
t
× 100
M
1
M
2
1
I
m
%Error
2
A6312 Instructions
23
DC Offset Adjustment
The following adjustment procedures describe how to adjust the DC offset of the
A6312 using the AM503, AM503A, AM503B or AM5030 amplifiers. Tolerances that are specified in these procedures apply to the current probes and do
not include test equipment error.
Refer to Figure 11 for the location of the DC offset adjustment.
Figure 11: A6312 DC offset adjustment location
Required Test Equipment
To perform the adjustment procedures in this section, you will need the test
equipment listed in Table 12. The test equipment must meet or exceed the
specifications listed. The test procedure may need to be changed if the recommended equipment is not used.
DC offset
24
Table 12: Required test equipment
Recommended
QtyItemDescription
1Oscilloscope150 MHz bandwidthTDS460
1Termination
3BNC cable
1
Provided as a standard accessory with the AM503 series amplifiers.
1
1
50 Ω, BNC connector,
feedthrough
50 Ω, 1.05 m (42 in) long012--0057--01
equipment
011--0049--01
A6312 Instructions
Equipment Connections
1. Connect the amplifier output to a 50 Ω oscilloscope input using a 50 Ω BNC
2. Connect the current probe to the amplifier input connector.
3. Do not clamp the current probe around a conductor, but make sure the jaws
AM503B or AM5030
Use the following procedure to adjust the DC offset of the A6312 current probe
when using an AM503B or AM5030 current probe amplifier.
DC Offset Adjustment
cable. If the input impedance of your oscilloscope is 1 MΩ, first connect a
50 Ω feedthrough termination to the oscilloscope input. Do not connect the
termination at the amplifier output.
are locked shut.
Equipment Settings
Procedure
Make or verify the equipment settings in Table 13:
Table 13: AM503B/AM 5030 settings for DC offset adjustment
Vertical Gain10 mV/division
Time BaseAuto triggered
1 ms/division,
Input CouplingGround
1. Move the oscilloscope trace to the center horizontal graticule line using the
vertical position control.
2. Set the oscilloscope input coupling to DC.
3. Do not clamp the current probe around a conductor, but make sure the jaws
are locked shut.
A6312 Instructions
4. Press the amplifier PROBE DEGAUSS AUTOBALANCE button. Wait for
the degauss/autobalance routine to complete before proceeding. The routine
is complete when the indicator light turns off.
25
DC Offset Adjustment
NOTE. If the amplifier is not properly terminated into 50 Ω, the amplifier front
panel displays error code 266 after the degauss/autobalance routine completes.
Verify that the oscilloscope input is 50 Ω and set to DC coupling. If necessary,
use a 50 Ω termination at the oscilloscope input.
5. If no error codes are displayed after the degauss/autobalance routine
completes, no offset adjustment is necessary. If any of the error codes listed
in Table 14 are displayed, continue with the procedure:
Table 14: AM 503B/AM 5030 error codes requiring DC offset adjustment
Error codeMeaning
580Unable to complete negative offset adjustment
581Unable to complete positive offset adjustment
6. Press and hold the 20 MHz BW LIMIT button, and while holding it, press the
PROBE DEGAUSS AUTOBALANCE button. This sets the front panel
display to --00 and puts the AM503B and AM5030 into an internal test
mode.
7. Press the CURRENT/DIVISION
button until the front panel display
reads --52.
8. Press and release the 20 MHz BW LIMIT button. The amplifier degausses
itself. Wait until the DEGAUSS light goes out.
9. Adjust the DC Offset control so that the oscilloscope trace is on the center
graticule line (zero offset), ± 2 divisions.
10. Press and release the 20 MHz BW LIMIT button, then press and release the
COUPLING button. This exits the AM503B and AM5030 test mode.
26
A6312 Instructions
AM503A
DC Offset Adjustment
Use the following procedure to adjust the DC offset of the A6312 current probe
when using an AM503A current probe amplifier.
Equipment Settings
Procedure
Make or verify the equipment settings in Table 15:
Table 15: AM503A settings for DC offset adjustment
Vertical gain10 mV/division
Time baseAuto triggered
1 ms/division,
Input couplingGround
1. Move the oscilloscope trace to the center horizontal graticule line using the
vertical position control.
2. Set the oscilloscope input coupling to DC.
3. Do not clamp the current probe around a conductor, but make sure the jaws
are locked shut.
A6312 Instructions
4. Press the AM503A PROBE DEGAUSS AUTOBALANCE button. Wait
for the degauss/autobalance routine to complete before proceeding. The
routine is complete when the indicator light turns off.
NOTE. If the AM503A is not properly terminated into 50 Ω,
the AM503A front
panel displays error code 54 after the degauss/autobalance routine completes.
Verify that the oscilloscope input is 50 Ω and set to DC coupling. If necessary,
use a 50 Ω termination at the oscilloscope input.
5. If no error codes are displayed after the degauss/autobalance routine
completes, no offset adjustment is necessary. If any of the error codes in
Table 16 are displayed, continue with the rest of this procedure.
27
DC Offset Adjustment
Table 16: AM503A error codes requiring DC offset adjustment
Error codeMeaning
46Unable to complete positive coarse offset adjustment
47Unable to complete negative coarse offset adjustment
48Unable to complete positive fine offset adjustment
49Unable to complete negative fine offset adjustment
6. Press and hold the 20 MHz BW LIMIT button, and while holding it, press the
PROBE DEGAUSS AUTOBALANCE button. This sets the front panel
display to 00 and puts the AM503A into an internal test mode.
7. Rotate the CURRENT/DIVISION knob until the front panel display
reads 21.
8. Press and release the 20 MHz BW LIMIT button. This sets the AM503A
internal offsets to zero.
9. Adjust the A6312 DC Offset control so that the oscilloscope trace is on the
center graticule line (zero offset), ± 2 divisions.
10. Press and release the 20MHz BW LIMIT button, then press and release the
DC COUPLING button. This exits the AM503A test mode.
28
A6312 Instructions
AM503
DC Offset Adjustment
Use the following procedure to adjust the DC offset of the A6312 current probe
when using an AM503 current probe amplifier.
Equipment Settings
Procedure
Make or verify the equipment settings in Table 17:
Table 17: AM 503 settings for DC offset adjustment
Vertical gain10 mV/division
Time baseAuto triggered
1 ms/division
Input couplingGround
1. Move the oscilloscope trace to the center horizontal graticule line using the
vertical position control.
2. Set the oscilloscope input coupling to DC.
3. Move the oscilloscope trace to the center horizontal graticule line using the
AM503 DC LEVEL control.
A6312 Instructions
4. Do not clamp the current probe around a conductor, but make sure the jaws
are locked shut.
5. Press and release the DEGAUSS button.
6. Set the AM503 input coupling to DC.
7. Set the AM503 BALANCE adjustment to mid--position.
8. Adjust the A6312 DC Offset control so that the oscilloscope trace is on the
center graticule line (zero offset), ± 2 divisions.
9. Press and release the DEGAUSS button.
10. If necessary, readjust the A6312 DC Offset control so that the oscilloscope
trace is on the center graticule line (zero offset), ± 2 divisions.
29
Maintenance
Cleaning
This section explains how to clean the A6312 current probe and, if necessary,
disassemble the probe for maintenance or repair. Also included are instructions
for preparing the probe for shipment.
WARNING. Probe disassembly should only be performed by qualified service
personnel.
To clean the probe body, use a soft cloth dampened in a solution of mild
detergent and water. To clean the core, open the jaw and clean the exposed core
surfaces with a cotton swap dampened with isopropyl alcohol (isopropanol) or
ethyl alcohol (fotocol or ethanol).
Do not lubricate the jaws mating surfaces. Any lubricant between the core pieces
should be removed with a recommended solvent.
Do not use chemicals containing benzine, benzene, toluene, xylene, acetone, or
similar solvents.
Do not use a petroleum based lubricant on the plastic. If the plastic slide
assembly requires lubrication, use a silicone based grease sparingly.
Do not immerse the probe in liquids or use abrasive cleaners.
Disassembly Instructions
WARNING. Probe disassembly should only be performed by qualified service
personnel.
1. Remove the two screws from the bottom of the probe and pull the strain
relief boot back as shown in Figure 12.
30
A6312 Instructions
Strain relief boot
Figure 12: Removing the strain relief boot
Maintenance
Probe body
Screws
2. Move the probe slide assembly to the open position.
NOTE. The probe slide contains a tiny metal ball. In step 3, be careful not to lose
the ball by accidentally letting it fall out.
3. Hold the probe in a top-up horizontal position and slide the top half of the
probe body off as shown in Figure 13.
4. Remove the metal ball.
5. Turn the probe upside down, push the slide back slightly, and remove the
slide (see Figure 14).
A6312 Instructions
31
Maintenance
Be careful to keep
this tiny metal ball
from falling out
(b)
(a)
(1) Hold the bottom
half of the probe
body in one hand
Figure 13: Removing the top half of the probe
(1) Hold the bottom half of
the probe body in one hand
(2) Grasp the top half of
the probe body here
with your other hand,
then
(a) pivot the back end
up, and
(b)slidethetopforward
off the end of the bottom
half of the probe body
(a)
(b)
32
(2) Grasp the top half of the probe
body here with your other hand,
then
(a) push the slide back slightly, and
(b) withdraw the slide from the
probe body
Figure 14: Removing the probe slide
A6312 Instructions
Maintenance
6. If you want to replace the current transformer, lift the front edge of the
circuit board and transformer out of the probe and then pull the transformer
out of the circuit board socket.
7. To remove the circuit board, unsolder the two connections then lift the strain
relief and circuit board from the body half. Refer to Figure 15.
Circuit board
Current
transformer
Body half
Figure 15: Removing the current transformer
8. Before reassembling the probe, be sure that the gap between the stationary
and moveable core pieces is clean. If necessary, use isopropyl alcohol or a
similar cleaning agent to clean the pieces. Also, clean the contacts of the
slide switch, if necessary. Should the plastic slide assembly require
lubrication, sparingly apply silicone-based grease to the parts.
Probe reassembly is the reverse of steps 1 through 7.
NOTE. Exercise care when fitting the slide back into the probe body; aligning the
switch contacts can require patience.
A6312 Instructions
33
Maintenance
Obtaining Replacement Parts
Replacement parts may be obtained through your local Tektronix field office or
representative. Refer to the Replaceable Parts List on page 35 for more information.
Preparation for Shipment
If you must ship your Tektronix product, please use the original packaging if
possible. If the original packaging is unfit for use or not available, use the
following packaging guidelines:
1. Use a corrugated cardboard shipping carton having inside dimensions at least
one inch greater than the probe dimensions. The box should have a carton
test strength of at least 200 pounds.
2. Put the probe into a plastic bag or wrap to protect it from dampness.
3. Place the probe into the box and stabilize it with light packing material.
4. Seal the carton with shipping tape.
34
A6312 Instructions
Replaceable Parts
This section contains a list of the components that are replaceable for the Current
Probe. As described below, use these lists to identify and order replacement
parts.
Parts Ordering Information
Replacement parts are available from or through your local Tektronix, Inc.,
service center or representative.
Changes to Tektronix instruments are sometimes made to accommodate
improved components as they become available and to give you the benefit of
the latest circuit improvements. Therefore, when ordering parts, it is important to
include the following information in your order:
HPart number
HInstrument type or model number
HInstrument serial number
HInstrument modification number, if applicable
If a part you order has been replaced with a different or improved part, your local
Tektronix service center or representative will contact you concerning any
change in the part number.
Using the Replaceable Parts List
The tabular information in the Replaceable Parts List is arranged for quick
retrieval. Understanding the structure and features of the list will help you find
all the information you need for ordering replacement parts.
Item Names
In the Replaceable Parts List, an Item Name is separated from the description by
a colon (:). Because of space limitations, an Item Name may sometimes appear
as incomplete. For further Item Name identification, U.S. Federal Cataloging
Handbook H6--1 can be used where possible.
A6312 Instructions35
Replaceable Parts
Indentation System
Abbreviations
This parts list is indented to show the relationship between items. The following
example is of the indentation system used in the Description column:
12345Name&Description
Assembly and/or Component
Attaching parts for Assembly and/or Component
(END ATTACHING PARTS)
Detail Part of Assembly and/or Component
Attaching parts for Detail Part
(END ATTACHING PARTS)
Parts of Detail Part
Attaching parts for Parts of Detail Part
(END ATTACHING PARTS)
Attaching parts always appear at the same indentation as the item it mounts,
while the detail parts are indented to the right. Indented items are part of, and
included with, the next higher indentation. Attaching parts must be purchased
separately, unless otherwise specified.
Abbreviations conform to American National Standards Institute (ANSI)
standard Y1.1.