Agilent Technologies U1251A Manual

Agilent Technologies
Agilent U1251A and
U1252A
Handheld Digital
Multimeter
User’s and Service Guide

2 Agilent U1251A/U1252A User’s and Service Guide
Notices
© Agilent Technologies, Inc. 2006, 2007
No part of this manual may be reproduced in
any form or by any means (including elec-
tronic storage and retrieval or translation
into a foreign language) without prior agree-
ment and written consent from Agilent
Technologies, Inc. as governed by United
States and international copyright laws.
Manual Part Number
U1251-90003
Edition
Fourth Edition, May 27, 2007
Printed in Malaysia
Agilent Technologies, Inc.
3501 Stevens Creek Blvd.
Santa Clara, CA 95052 USA
Technology Licenses
The hardware and/or software described in
this document are furnished under a license
and may be used or copied only in accor-
dance with the terms of such license.
Restricted Rights Legend
U.S. Government Restricted Rights. Soft-
ware and technical data rights granted to
the federal government include only those
rights customarily provided to end user cus-
tomers. Agilent provides this customary
commercial license in Software and techni-
cal data pursuant to FAR 12.211 (Technical
Data) and 12.212 (Computer Software) and,
for the Department of Defense, DFARS
252.227-7015 (Technical Data - Commercial
Items) and DFARS 227.7202-3 (Rights in
Commercial Computer Software or Com-
puter Software Documentation).
Warranty
The material contained in this docu-
ment is provided “as is,” and is sub-
ject to being changed, without notice,
in future editions. Further, to the max-
imum extent permitted by applicable
law, Agilent disclaims all warranties,
either express or implied, with regard
to this manual and any information
contained herein, including but not
limited to the implied warranties of
merchantability and fitness for a par-
ticular purpose. Agilent shall not be
liable for errors or for incidental or
consequential damages in connec-
tion with the furnishing, use, or per-
formance of this document or of any
information contained herein. Should
Agilent and the user have a separate
written agreement with warranty
terms covering the material in this
document that conflict with these
terms, the warranty terms in the sep-
arate agreement shall control.
Accessories Warranty
Agilent offers warranty for product’s acces-
sories for up to 3 months from the end-user
acceptance date.
Standard Calibration Service
(optional)
Agilent offers an optional calibration service
contract for a period of 3 years from
end-user acceptance date.
Safety Notices
CAUTION
A CAUTION notice denotes a haz-
ard. It calls attention to an operat-
ing 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 beyond a
CAUTION notice until the indicated
conditions are fully understood and
met.
WARNING
A WARNING notice denotes a
hazard. It calls attention to an
operating procedure, practice, or
the like that, if not correctly per-
formed or adhered to, could result
in personal injury or death. Do not
proceed beyond a WARNING
notice until the indicated condi-
tions are fully understood and
met.

Agilent U1251A/U1252A User’s and Service Guide 3
Safety Information
This meter is safety-certified in compliance with EN/IEC 61010-1:2001, UL 61010-1 Second Edition and CAN/CSA
22.2 61010-1 Second Edition, Category III 1000 V Overvoltage Protection, Pollution Degree II. Use with standard or
compatible test probes.
WARNING
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
beyond a CAUTION notice until the indicated conditions are fully understood and met.
Use the meter only as specified in this guide. Otherwise, the protection provided by the meter may be impaired.
Refer to the safety information below:
•When working above 70V DC, 33 V AC RMS or 46.7 V peak, exercise caution – such range pose a shock
hazard.
•Do not measure more than the rated voltage (as marked on the meter) between terminals, or between terminal
and earth ground.
•Double-check the meter’s operation by measuring a known voltage.
•For current measurement, turn off circuit power before connecting the meter to the circuit. Always place the
meter in series with the circuit.
•When connecting probes, always connect the common test probe first. When disconnecting probes, always
disconnect the live test probe first.
•Detach test probes from the meter before you open the battery cover.
•Do not use the meter with the battery cover or part of the cover removed or loose.
•Replace the battery as soon as the low battery indicator flashes on screen. This is to avoid false readings,
which may lead to possible electric shock or personal injury.
•Do not operate the product in an explosive atmosphere or in the presence of flammable gases or fumes.

4 Agilent U1251A/U1252A User’s and Service Guide
•Inspect the case for cracks or missing plastic. Pay extra attention to the insulation surrounding the
connectors. Do not use the meter if it is damaged.
•Inspect the test probes for damaged insulation or exposed metal, and check for continuity. Do not use the test
probe if it is damaged.
•Do not use any other AC charger adaptor apart from the one certified by Agilent with this product.
•Do not use repaired fuses or short-circuited fuse-holders. For continued protection against fire, replace the
line fuses only with fuses of the same voltage and current rating and recommended type.
•Do not service or perform adjustments alone. Under certain condition, hazardous voltages may exist, even
with the equipment switched off. To avoid dangerous electric shock, service personnel must not attempt
internal service or adjustment unless another person, capable of rendering resuscitation or first aid, is present.
•Do not substitute parts or modify equipment to avoid the danger of introducing additional hazards. Return the
product to Agilent Technologies Sales and Service Office for service and repair to ensure the safety features
are maintained
• Do not operate damaged equipment as the safety protection features built into this product may have been
impaired, either through physical damage, excessive moisture, or any other reason. Remove power and do not
use the product until safe operation can be verified by service-trained personnel. If necessary, return the
product to Agilent Technologies Sales and Service Office for service and repair to ensure the safety features
are maintained.
•Turn off circuit power and discharge all high-voltage capacitors in the circuit before you perform resistance,
continuity, diodes, or capacitance tests.
•Use the correct terminals, function, and range for your measurements.
•Never measure voltage when current measurement is selected.
•Use only recommended rechargeable battery. Ensure proper insertion of battery in the meter, and follow the
correct polarity.
• Disconnect test leads from all the terminals during battery charging.

Agilent U1251A/U1252A User’s and Service Guide 5
Safety Symbols
CAT III
1000 V
Category III 1000 V Overvoltage Protection
Double insulation
Earth ground
Caution, risk of danger
(Refer to the User’s and Service Guide for details)
Caution, risk of electric shock

6 Agilent U1251A/U1252A User’s and Service Guide
Regulatory Markings
The CE mark is a registered trademark of the European
Community.This CE mark shows that the product complies with
all the relevant European Legal Directives. If it was accompanied
by a year, it indicates the year the design was approved. This ISM
device complies with Canadian ICES-001.
The CSA mark is a registered trademark of the Canadian
Standards Association.
The UL mark is a registered trademark of Underwriters
Laboratories Inc.
The C-tick mark is a registered trademark of the Spectrum
Management Agency of Australia. This signifies compliance with
the Australia EMC Framework regulations under the terms of the
Radio Communication Act of 1992.
This instrument complies with the WEEE Directive (2002/96/EC)
marking requirement. This affixed product label indicates that
you must not discard this electrical/electronic product in
domestic household waste.

Agilent U1251A/U1252A User’s and Service Guide 7
DECLARATION OF CONFORMITY
According to ISO/IEC Guide 22 and CEN/CENELEC EN 45014
Generic example
Manufacturer’s Name: Agilent Technologies Microwave Products (M) Sdn. Bhd
Manufacturer’s Address: Bayan Lepas Free Industrial Zone,
11900, Bayan Lepas, Penang, Malaysia
Declares under sole responsibility that the product as originally delivered
Product Name: Handheld Digital Multimeter
Model Number: U1251A, U1252A
Product Options: This declaration covers all options of the above product(s)
complies with the essential requirements of the following applicable European Directives, and
carries the CE marking accordingly:
Low Voltage Directive (73/23/EEC, amended by 93/68/EEC)
EMC Directive (89/336/EEC, amended by 93/68/EEC)
and conforms with the following product standards:
EMC Standard
StandardStandard
Standard
Limit LimitLimit
Limit
IEC 61326-1:1997+A1:1998 / EN 61326-1:1997+A1:1998
CISPR 11:1990 / EN55011:1991 Class A Group 1
IEC 61000-4-2:1995+A1:1998 / EN 61000-4-2:1995 4 kV CD, 8 kV AD
IEC 61000-4-3:1995 / EN 61000-4-3:1995 3 V/m, 80-1000 MHz
IEC 61000-4-4:1995 / EN 61000-4-4:1995 0.5 kV signal lines, 1 kV power lines
IEC 61000-4-5:1995 / EN 61000-4-5:1995 0.5 kV line-line, 1 kV line-ground
IEC 61000-4-6:1996 / EN 61000-4-6:1996 3 V, 0.15-80 MHz
IEC 61000-4-11:1994 / EN 61000-4-11:1994 1 cycle / 100%
Canada: ICES-001:1998
Australia/New Zealand: AS/NZS 2064.1
The product was tested in a typical configuration with Agilent Technologies test systems.
Safety IEC 61010-1:2001 / EN 61010-1:2001
Canada: CSA C22.2 No. 61010-1:2004
USA: UL 61010-1: 2004
Supplementary Information:
U1251A is provided with 9Vdc non-rechargeable battery, without AC power adaptor.
U1252A is provided with 9Vdc rechargeable battery, with AC power adaptor (U1170A).
IEC/EN61000-4-4, -4-5, -4-6, -4-11 are applicable for the AC power adaptor configuration for model U1252A.
This DoC applies to above-listed products placed on the EU market after:
22-August-2006
Date
Mack Soh
Quality Manager
For further information, please contact your local Agilent Technologies sales office, agent or distributor,
or Agilent Technologies Deutschland GmbH, Herrenberger Straße 130, D 71034 Böblingen, Germany.
Template: A5971-5302-2, Rev. B.01 U1251A Rev 1.0

8 Agilent U1251A/U1252A User’s and Service Guide
Product Regulations
Performance Criteria
1
IEC 61326-1:1997+A1:1998 / EN 61326-1:1997+A1:1998 U1251A U1252A
CISPR 11:1990 / EN 55011:1991 – Group 1 Class A
IEC 61000-4-2:1995+A1:1998 / EN 61000-4-2:1995 (ESD
4kV CD, 8kV AD)
B B
IEC 61000-4-3:1995 / EN 61000-4-3:1995 (3V/m, 80% AM) A A
IEC 61000-4-4:1995 / EN 61000-4-4:1995 (EFT 0.5kV line-
line, 1kV line-earth)
N/A A
IEC 61000-4-5:1995 / EN 61000-4-5:1995 (Surge 0.5kV line-
line, 1kV line-earth)
N/A A
IEC 61000-4-6:1996 / EN 61000-4-6:1996 (3V, 0.15~80 MHz,
80% AM, power line)
N/A A
IEC 61000-4-11:1994 / EN 61000-4-11:1994 (Dips 1 cycle,
100%)
N/A A
Canada: ICES-001:1998
Australia/New Zealand: AS/NZS 2064.1
EMC
IEC 61010-1:2001 / EN 61010-1:2001
Canada: CSA C22.2 No. 61010-1:2004
Safety
USA: UL 61010-1: 2004
Additional Information:
The product herewith complies with the essential requirements of the Low Voltage Directive 73/23/EEC and the
EMC Directive 89/336/EEC (including 93/68/EEC) and carries the CE Marking accordingly (European Union).
1
Performance Criteria:
A Pass - Normal operation, no effect.
B Pass - Temporary degradation, self recoverable.
C Pass - Temporary degradation, operator intervention required.
D Fail - Not recoverable, component damage.
N/A – Not applicable
Notes:
Regulatory Information for Canada
ICES/NMB-001:1998
This ISM device complies with Canadian ICES-001.
Cet appareil ISM est confomre à la norme NMB-001 du Canada.
Regulatory Information for Australia/New Zealand
This ISM device complies with Australian/New Zealand AS/NZS 2064.1

Agilent U1251A/U1252A User’s and Service Guide 9
Contents
1 Getting Started Tutorial 13
Introducing the Agilent U1251A and U1252A Handheld Digital
Multimeter 14
Adjusting the Tilt-Stand 15
The Front Panel at a Glance 17
The Rotary Switch at a Glance 18
The Keypad at a Glance 19
The Display at a Glance 21
Selection of Display by Hz Button 25
Selection of Display by Dual Button 27
Selection of Display by SHIFT Button 30
The Terminals at a Glance 32
The Rear Panel at a Glance 33
2 Making Measurements 35
Measuring Voltage 36
Measuring Current 39
Measuring DC voltage 38
Measuring Current 39
µA & mA Measurement 39
% Scale of 4–20 mA 40
A measurement 41
Frequency Counter 42
Measuring Resistance, Conductance and Testing Continuity 44
Te st i ng D io d e s 48
Measuring Capacitance 51
Measuring Temperature 52
Alerts and Warning During Measurement 55
Overload Alert 55
Input Warning 55
Charge Terminal Alert 56

10 Agilent U1251A/U1252A User’s and Service Guide
Contents
3 Features and Functions 57
Dynamic Recording 58
Data Hold (Trigger Hold) 60
Refresh Hold 61
NULL (Relative) 63
Decibel Display 65
1 ms Peak Hold 67
Data Logging 69
Manual Logging 69
Interval Logging 71
Reviewing Logged Data 73
Square Wave Output (for U1252A) 75
Remote Communication 80
4 Changing The Default Setting 81
Selecting Setup Mode 82
Setting Data Logging Mode 86
Setting Thermocouple Types (for U1252A) 87
Setting Reference Impedance for dBm Measurement 88
Setting Minimum Frequency Measurement 89
Setting Temperature Unit 90
Setting Auto Power Saving Mode 92
Setting % Scale Readout 94
Setting Beep Frequency 95
Setting Backlit Timer 96
Setting Baud Rate 97
Setting Parity Check 98
Setting Data Bit 99
Setting Echo Mode 100
Setting Print Mode 101
Returning to Default Factory Settings 102
5 Maintenance 103
Introduction 104
General Maintenance 104
Battery Replacement 105
Charging Battery 106
Fuse Replacement 113

Contents
Agilent U1251A/U1252A User’s and Service Guide 11
Troubleshooting 115
6 Accessories 117
Checking the Shipping Contents 118
List of Accessories 119
7 Performance Tests and Calibration 121
Calibration Overview 122
Closed - case Electronic Calibration 122
Agilent Technologies Calibration Services 122
Calibration Interval 122
Adjustment is Recommended 123
Recommended Test Equipment 124
Basic Operating Test 125
Backlit Test 125
Testing the Display 125
Current Terminal Test 126
C h ar g e Te r m i na l A le r t Te s t 127
Te s t C o n s i de r a t io n s 128
Input Connections 129
Performance Verification Tests 130
Calibration Security 138
Unsecuring the Instrument for Calibration 139
Calibration Process 142
Using the Front Panel for Adjustments 143
Adjustments Consideration 144
Valid Adjustment Input Values 145
Adjustment Procedure 146
Finishing the Adjustment 153
To Re a d th e C a li b ra ti o n Co u n t 153
Calibration Errors 154
8 Specifications 155
DC Specifications 158
U1251A AC Specifications 160
U1252A AC Specifications 161

12 Agilent U1251A/U1252A User’s and Service Guide
Contents
U1252A AC+DC Specifications 162
Temperature and Capacitance Specifications 163
U1251A & U1252A Frequency Specifications(1) 164
Operating Specifications 167
General Specifications 168

13Agilent Technologies
Agilent U1251A and U1252A Handheld Digital Multimeter
User’s and Service Guide
1
Getting Started Tutorial
Introducing the Agilent U1251A and U1252A Handheld Digital
Multimeter 14
Adjusting the Tilt-Stand 15
The Front Panel at a Glance 17
The Rotary Switch at a Glance 18
The Keypad at a Glance 19
The Display at a Glance 21
Selection of Display by Hz Button 25
Selection of Display by Dual Button 27
Selection of Display by SHIFT Button 30
The Terminals at a Glance 32
The Rear Panel at a Glance 33
This chapter contains a brief description on the front panel
of the Agilent U1251A and U1252A Handheld Digital
Multimeter.

14 Agilent U1251A/U1252A User’s and Service Guide
1 Getting Started Tutorial
Introducing the Agilent U1251A and U1252A Handheld Digital Multimeter
The handheld digital multimeters’ key features are:
•DC, AC and AC + DC (only U1252A) voltage and current
measurements.
•True- RMS measurement for both AC voltage and current
•Rechargeable Ni- MH battery with built- in charging
capability (only U1252A)
•Ambient temperature on second display
•Battery capacity indicator
•Blue LED backlight
•Resistance measurement up to 50M
Ω (for U1251A) and
500M
Ω (for U1252A)
•Conductance measurement from 0.01nS (100G
Ω ) ~ 50nS
•Capacitance measurement up to 100mF
•Frequency counter up to 20MHz (only U1252A)
•The % scale readout for 4- 20mA or 0- 20mA measurement
•dBm with selectable reference impedance
•1ms Peak Hold to catch inrush voltage and current easily
•Temperature test with selectable 0 °C compensation
(without ambient temperature compensation).
•K- type (for U1251A) and J/K- types temperature
measurement (for U1252A)
•Frequency, duty cycle and pulse width measurements
•Dynamic Recording for min, max and average readings
•Data Hold with manual or auto trigger and Null mode
•Diode and audible continuity tests
•Square wave generator with selectable frequency, pulse
width and duty cycle (only U1252A)
•Agilent GUI Application Software (IR- USB cable sold
separately)
•Closed case calibration

Getting Started Tutorial 1
Agilent U1251A/U1252A User’s and Service Guide 15
•50,000 count precision true RMS digital multimeter,
designed to meet EN/IEC 61010- 1:2001 Category III 1000
V Overvoltage Protection, Pollution Degree II standards
Adjusting the Tilt-Stand
To adjust the meter to a 60°standing position, pull the
tilt- stand outwards to its maximum reach.
To adjust the meter to a 30°standing position, bend the tip
of the stand so that it is parallel to ground before pulling
the stand outwards to its maximum reach.
IR-USB cable
To P C
(host)
Tilt-stand at 30 º
IR-USB cable
To P C
(host)
Tilt-stand at 60°

Getting Started Tutorial 1
Agilent U1251A/U1252A User’s and Service Guide 16
To adjust the meter to a hanging position, flip the stand
upwards and over its maximum reach until it is detached
from its hinge. Then flip the stand over so that the stand’s
inner surface is facing the meter’s rear. Now, press the stand
down into its hinge. Follow the step by step pictorial
instructions below.

Getting Started Tutorial 1
Agilent U1251A/U1252A User’s and Service Guide 17
The Front Panel at a Glance
Display
Keypad
Rotary switch
Display
Ter mi nals

18 Agilent U1251A/U1252A User’s and Service Guide
1 Getting Started Tutorial
The Rotary Switch at a Glance
Legend:
No. Description / Function
1Chargemode[U1252A only] or OFF
2ACV
3 DC voltage or DC+AC voltage [U1252A only]
4 DC mV, AC mV, AC+DC mV [U1252A only]
5 Resistance (
Ω ), Continuity, and Conductance ( nS )
6 Frequency counter [U1252A only] or Diode
7 Capacitance or Temperature
8DCµAandACµA
9 DC mA, DC current, AC mA or AC current
10 Square-wave output, Duty cycle or Pulse width output [for
U1252A] and OFF [for U1251A]
1
2
3
4
5
6 7
8
9
10

Getting Started Tutorial 1
Agilent U1251A/U1252A User’s and Service Guide 19
The Keypad at a Glance
The operation of each key is shown below. Pressing a key
illuminates a related symbol on the display and sounds the
beeper. Turning the rotary switch to another position resets
the current operation of the key.
Figure 1 shows the keypad of the U1252A. The ms% (Pulse
width/Duty cycle), Hz , and frequency counter
functions are only available on the U1252A.
Figure 1 U1252A Keypad
Ta b l e 1 Keypad Desciption/Functions
Function when pushed for less than 1 second Function when pushed for more than 1 second
1acts as a toggle switch to turn backlit
ON/OFF. Backlit automatically turns off after 30s
(default)(1).
displays battery capacity for 3 seconds
2freezes measured value. In Data Hold mode, push
again to trigger hold of the next measured value. In
Refresh Hold mode, reading updates automatically
once reading is stable and count setting is
exceeded(1).
enters Dynamic Recording mode. Push
again to scroll through Max, Min, Avg and
present (indicated by MAXMINAVG on display)
readings.
3saves displayed value as a reference to be
subtracted from subsequent measurements. Push
again to see the relative value that has been saved.
enters 1 ms Peak Hold mode. Push
to scroll through Max and Min peak readings.

20 Agilent U1251A/U1252A User’s and Service Guide
1 Getting Started Tutorial
Function when pushed for less than 1 second Function when pushed for more than 1 second
4scrolls through measuring function(s) at a
particular rotary switch position.
enters Log Review mode. Push
to switch to manual or interval logging data. Push
or to view first or last logged data respectively.
Push or to scroll up or down logged data.
Push for more than 1 second to exit mode.
5scrolls through available measuring ranges
(except when rotary switch is at TEMP or Hz [for
U1252A] position)(2).
sets to Auto Range mode.
6scrolls through available dual-combination
displays (except when rotary switch is at TEMP or
[for U1252A] position, or when meter is in 1 ms
peak hold or dynamic recording mode)(3).
exits Hold, Null, Dynamic Recording, 1 ms
Peak Hold and dual display modes.
7enters Frequency Test mode for current or
voltage measurements. Push to scroll
through frequency (Hz), duty cycle (%) and pulse width
(ms) functions. In duty cycle (%) and pulse width (ms)
tests, push to switch to positive or negative
pulse.
enters logging mode. In manual data logging,
push to log data manually into memory. In
automatic data logging, data logs automatically(1) .
Push for more than 1 second to exit auto data
logging mode.
NOTE 1. See Ta b l e 3, “Available setting options in Setup mode,” for details of
available options.
2. When rotary switch is at TEMP, push to switch to ºC or ºF display. When
rotary swtich is at Hz, push to switch to division of signal frequency by 1 or
100.
3. When rotary switch is at TEMP, ETC is ON by default. You may push to
disable ETC (Environment Temperature Compensation), will appear on display.
For pulse and duty cycle measurement, push to switch trigger slope to
positive or negative. When meter is in peak or dynamic-recording mode, push
to restart 1 ms peak hold or dynamic recording mode.