Agilent Technologies U2741A User Manual
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Agilent Technologies U2741A User Manual

Agilent Technologies U2741A User Manual

Usb modular 5.5 digits digital multimeter
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Agilent U2741A USB
Modular 5.5 Digits

Digital Multimeter

User's Guide
Agilent Technologies

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Summary of Contents for Agilent Technologies U2741A

  • Page 1: Digital Multimeter

    Agilent U2741A USB Modular 5.5 Digits Digital Multimeter User’s Guide Agilent Technologies...

  • Page 2: Trademark Acknowledgements

    Notices Warranty Safety Notices ® Agilent Technologies, Inc. , 2008 - 2012 No part of this manual may be reproduced in The material contained in this docu- any form or by any means (including elec- ment is provided “as is,” and is sub-...

  • Page 3: Safety Symbols

    Safety Symbols The following symbols on the instrument and in the documentation indicate precautions which must be taken to maintain safe operation of the instrument. Direct current (DC) Off (supply) Alternating current (AC) On (supply) Both direct and alternating current Caution, risk of electric shock Three-phase alternating current Caution, risk of danger (refer to this manual...
  • Page 4 General Safety Information • Do not use the device if it is damaged. Before you use the device, WA R N I N G inspect the casing. Look for cracks or missing plastic. Do not operate the device around explosive gas, vapor, or dust. •...

  • Page 5: Environmental Conditions

    Environmental Conditions This instrument is designed for indoor use and in an area with low condensation. The table below shows the general environmental requirements for this instrument. Environmental conditions Requirements Operating temperature 0 °C to 55 °C Operating humidity 20% to 85% RH non-condensing Storage temperature –20 °C to 70 °C Storage humidity...
  • Page 6 Regulatory Markings The CE mark is a registered trademark The C-tick mark is a registered of the European Community. This CE trademark of the Spectrum mark shows that the product complies Management Agency of Australia. with all the relevant European Legal This signifies compliance with Directives.
  • Page 7 Waste Electrical and Electronic Equipment (WEEE) Directive 2002/96/EC 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. Product Category: With reference to the equipment types in the WEEE directive Annex 1, this instrument is classified as a “Monitoring and Control Instrument”...

  • Page 8: Getting Started

    In This Guide… Getting Started This chapter provides an overview of the U2741A USB modular digital multimeter, the product outlook, product dimension, and product layout. This chapter contains instructions on how to install and configure to get started with the U2741A. Operation and Features In this chapter, you will get to learn more about the operations and features that are offered by the U2741A.
  • Page 9 Declaration of Conformity (DoC) The Declaration of Conformity (DoC) for this instrument is available on the Web site. You can search the DoC by its product model or description. http://regulations.corporate.agilent.com/DoC/search.htm If you are unable to search for the respective DoC, please contact your N O T E local Agilent representative.
  • Page 10 U2741A User’s Guide...

  • Page 11: Table Of Contents

    Contents List of Figures XIII List of Tables Getting Started Introduction Product at a Glance Product Outlook Product Dimensions Dimensions without Bumpers Dimensions with Bumpers Standard Shipped Items Inspection and Maintenance Initial Inspection Electrical Check General Maintenance Installation and Configuration Instrument Configuration 55-Pin Backplane Connector Pin Configuration Chassis Installation...
  • Page 12 Contents Measuring AC Voltage Measuring DC Current Measuring AC Current Measuring Resistance Measuring Frequency Testing Continuity Testing Diodes Measuring Temperature Restoring Instrument State Autozero Ranging Default Settings Triggering the U2741A System-Related Operation Error Conditions Measurement Tutorial DC Measurement Considerations Noise Rejection Resistance Measurement Considerations AC Measurements Other Primary Measurement Functions...

  • Page 13: List Of Figures

    List of Figures Figure 1-1 55-pin backplane connector pin configuration Figure 3-1 Common mode source error Figure 3-2 Ground loop induced error Figure 3-3 Burden voltage in current measurement U2741A User’s Guide XIII...
  • Page 14 Contents U2741A User’s Guide...

  • Page 15: List Of Tables

    List of Tables Table 1-1 SSI connector pin description Table 2-1 Default settings summary Table 3-1 Thermoelectric voltage for dissimilar metals connections Table 3-2 Power dissipation for various resistance ranges Table 3-3 Waveform shapes and their parameters Table 4-1 DC accuracy Table 4-2 AC accuracy for voltage Table 4-3...
  • Page 16 Contents U2741A User’s Guide...

  • Page 17: Product At A Glance

    Product at a Glance Product Outlook Product Dimensions Dimensions without Bumpers Dimensions with Bumpers Standard Shipped Items Inspection and Maintenance Initial Inspection Electrical Check General Maintenance Installation and Configuration Instrument Configuration 55-Pin Backplane Connector Pin Configuration Chassis Installation Agilent Technologies...

  • Page 18: Getting Started

    Getting Started Introduction The Agilent U2741A is a 5.5 digits digital multimeter that can operate as standalone or as a modular unit when used with the U2781A USB modular instrument chassis. U2741A can perform the following measurements: • DC Voltage •...

  • Page 19: Product At A Glance

    Getting Started Product at a Glance Product Outlook Top view Bumpers U2741A User’s Guide...
  • Page 20 Getting Started Front view 4-wire Ω Lo Sense 4-wire Ω Hi Sense VOLT LO VOLT HI USB Indicator Power Indicator Fuse holder Rear view 55-pin backplane connector USB inlet Power inlet Fastening hole for USB cable with locking mechanism U2741A User’s Guide...

  • Page 21: Product Dimensions

    Getting Started Product Dimensions Dimensions without Bumpers Top view 105.00 mm 175.00 mm 11.50 mm Front view 25.00 mm U2741A User’s Guide...

  • Page 22: Dimensions With Bumpers

    Getting Started Dimensions with Bumpers Top view 117.00 mm 180.00 mm 8.60 mm Front view 41.00 mm U2741A User’s Guide...

  • Page 23: Standard Shipped Items

    Getting Started Standard Shipped Items Verify that you have received the following items with your unit. If anything is missing or damaged, please contact the nearest Agilent Sales Office. ✔ 12 V, 2 A AC/DC adapter ✔ Power cord ✔ Standard Test Lead ✔...

  • Page 24: Inspection And Maintenance

    Getting Started Inspection and Maintenance Initial Inspection When you receive your U2741A, inspect the unit for any obvious damage such as broken terminals or cracks, dents, and scratches on the casing that may occur during shipment. If any damage is found, notify the nearest Agilent Sales Office immediately.

  • Page 25: General Maintenance

    Getting Started General Maintenance General maintenance Any repair that is not covered in your modular product manuals should N O T E only be performed by qualified personnel. 1 Power off your module and remove the power cord and I/O cable from your device. 2 Remove your module from the bumper casing.

  • Page 26: Installation And Configuration

    Getting Started Installation and Configuration Follow the step-by-step instructions shown in the Agilent USB Modular Products and Systems Quick Start Guide to get started with the preparations and installations of your U2741A. You need to install the IVI-COM driver if you are going to use the U2741A N O T E ®...

  • Page 27: Instrument Configuration

    Getting Started Instrument Configuration 55-Pin Backplane Connector Pin Configuration The 55- pin backplane connector is used when the U2741A module is inserted into the U2781A USB modular instrument chassis. For more details, refer to the Agilent U2781A USB Modular Instrument Chassis User's Guide. VBUS –...

  • Page 28: Chassis Installation

    Getting Started Table 1-1 SSI connector pin description SSI timing signal Functionality CLK10M 10 MHz clock source STAR_TRIG Star trigger GA0,GA1,GA2 Geographical address pin Chassis Installation The L- Mount kit is to be installed to your U2741A module. The following instructions describe the simple procedure of installing the L- Mount kit and your module in the chassis.
  • Page 29 Error Conditions This chapter contains the details on how to configure your U2741A USB modular digital multimeter to perform the various measurement functions either through the software front panel or by sending SCPI commands remotely via the USB interface. Agilent Technologies...

  • Page 30: Operation And Features

    Operation and Features Powering Up Take note of the following when you power up the U2741A. • The U2741A can only be operated via the USB interface. • Before you can control the U2741A, you need to install the hardware driver and the IO Libraries Suite 14.2 or higher.

  • Page 31: Making Measurements

    Operation and Features Making Measurements The following pages show how to make measurement connections and how to select measurement functions from the front panel for each of the measurement functions. Measuring DC Voltage The DC voltage measurement function has the following features: •...
  • Page 32 Operation and Features Agilent Measurement Manager operation Select the DCV function and desired range. A suitable range should be selected to give the best measurement resolution. The reading is displayed and updated continuously. SCPI commands The following example shows how to make a DC voltage measurement using SCPI commands.

  • Page 33: Measuring Ac Voltage

    Operation and Features Measuring AC Voltage The AC voltage measurement function has the following features: • Five ranges to select: 100 mVrms, 1 Vrms, 10 Vrms, 100 Vrms, and 250 Vrms or, auto- range. • Measures the AC -coupled true rms. •...

  • Page 34: Measuring Dc Current

    Operation and Features SCPI commands The following example shows how to make an AC voltage measurement using SCPI commands. MEASure[:VOLTage]:AC? Measuring DC Current The DC current measurement function has the following features: • Three ranges to select: 10 mA, 100 mA, 1 A and 2 A or, auto- range.

  • Page 35: Measuring Ac Current

    Operation and Features SCPI commands The following example shows how to make a DC current measurement using SCPI commands. MEASure:CURRent[:DC]? Measuring AC Current The AC current measurement function has the following features: • Three ranges to select: 10 mA, 100 mA, 1 A and 2 A or, auto- range.

  • Page 36: Measuring Resistance

    Operation and Features SCPI commands The following example shows how to make an AC current measurement using SCPI commands. MEASure:CURRent:AC? Measuring Resistance The resistance measurement function has the following features: • Seven ranges to select: 100 Ω, 1 kΩ , 10 kΩ , 100 kΩ, 1 MΩ, 10 MΩ, and 100 MΩ...
  • Page 37 Operation and Features The following figure shows a four- wire resistance measurement connection. Test Current Agilent Measurement Manager operation Select the 2-Wired Ω function and desired range for two- wire resistance measurement. Select the 4-Wired Ω function and desired range for four- wire resistance measurement. A suitable range should be selected to give the best measurement resolution.

  • Page 38: Measuring Frequency

    Operation and Features Measuring Frequency The frequency measurement function has the following features: • Range is based on the amplitude of the signal. • Employs a reciprocal counting technique as the measurement method. • Gate time can be set at 0.1 second or 1 second of the input signal.

  • Page 39: Testing Continuity

    Operation and Features Testing Continuity The continuity testing function has the following features: • Uses a 1 mA ± 0.2% constant current source. • Open circuit voltage is limited to less than 4.5 V for all ranges. • Continuity threshold is fixed at 10 Ω. •...

  • Page 40: Testing Diodes

    Operation and Features Testing Diodes The diode testing function has the following features: • Uses a 1 mA ± 0.2% constant current source. • Open circuit voltage is limited to less than 4.5 V for all ranges. • Response time is 60 samples/second. Make the connection as shown below.

  • Page 41: Measuring Temperature

    Operation and Features Measuring Temperature The temperature measurement function has the following features: • The measurement range is dependant on the type of temperature sensor used. For the specification details of the temperature sensors, please refer to Table 4- 8 page 71.
  • Page 42 Operation and Features SCPI commands The following example shows how to make a temperature measurement using SCPI commands. //Used for thermistor MEASure:TEMPerature? THER measurement U2741A User’s Guide...

  • Page 43: Restoring Instrument State

    Operation and Features Restoring Instrument State The U2741A automatically saves the last configuration whenever a power- down event occurs and restores to the last power- down state when you turn on the instrument. Autozero When autozero is enabled, the digital multimeter internally disconnects the input signal following each measurement, and takes a zero reading.

  • Page 44: Ranging

    Operation and Features Ranging You can let the digital multimeter automatically select the range using auto range or you can select a fixed range using manual range. Autoranging is convenient because the digital multimeter automatically selects the appropriate range for each measurement.

  • Page 45: Default Settings

    Operation and Features Default Settings The table below summarizes the U2741A's settings as received from the factory, at power- on or following the *RST command received over the USB remote interface. Table 2-1 Default settings summary Parameter Factory Setting Power-on/Reset State Measurement Configuration Function Range...

  • Page 46: Triggering The U2741A

    Operation and Features Triggering the U2741A At power- up, the default trigger source is immediate. To make a measurement, the following steps are to be followed: • Configure the U2741A by selecting the function, range, resolution, and so on. • Specify the digital multimeter's trigger source. You can select software bus trigger or an immediate internal trigger (default trigger source).
  • Page 47 Operation and Features The INITiate command changes the state of the triggering to wait- for- trigger state. Measurements will begin when the specified trigger conditions are satisfied. Star Triggering The star trigger can only be applied when the U2741A is connected into the U2781A modular instrument chassis.

  • Page 48: System-Related Operation

    Operation and Features System-Related Operation This section provides information on system- related topics such as performing a self- calibration routine and reading error conditions. Error Conditions A record of up to 20 errors can be stored in the U2741A's error queue. Refer to the programming guide for more information on the error messages.

  • Page 49: Measurement Tutorial

    This chapter describes common errors found in measurements and gives suggestions to help you avoid or minimize these errors. Agilent Technologies...

  • Page 50: Dc Measurement Considerations

    Measurement Tutorial DC Measurement Considerations Thermal EMF errors Thermoelectric voltages are the most common source of error in low- level DC voltage measurements. Thermoelectric voltages are generated when you make circuit connections using dissimilar metals at different temperatures. Each metal- to- metal junction forms a thermocouple, which generates a voltage proportional to the junction temperature.

  • Page 51: Noise Rejection

    Measurement Tutorial Noise Rejection Rejecting power-line noise voltages An important property of integrating analog- to- digital (A/D) converters is their ability to reject power- line related noise that is present on the DC input signals. This is called normal mode noise rejection, or NMR. The digital multimeter achieves NMR by measuring the average DC input by "integrating"...
  • Page 52 Measurement Tutorial Noise caused by magnetic loops If you are making measurements near magnetic fields, it is a good practice to avoid inducing voltages in the measurement connections. Conductor carrying high current is one common source of magnetic field. You can use twisted- pair cable connections to the digital multimeter to reduce the noise pickup loop area, or place the test leads as close together as possible.
  • Page 53 Measurement Tutorial = Lead Resistance = digital multimeter Isolation Resistance Ideal test = Voltage Drop or Ground Bus ground Meter > 10GΩ ground Figure 3-2 Ground loop induced error The best way to eliminate ground loops is to isolate the digital multimeter from earth by not grounding the input terminals.

  • Page 54: Resistance Measurement Considerations

    Measurement Tutorial Resistance Measurement Considerations When measuring resistance, the test current flows from the input HI terminal through the resistor being measured. The voltage drop across the resistor being measured is sensed internally in the digital multimeter. Therefore, the test lead resistance is also measured.
  • Page 55 Measurement Tutorial Removing test lead resistance errors To eliminate offset errors associated with the test lead resistance in 2- wire ohms measurements, follow the steps below. 6 Short the tips of the test leads. The reading is the test lead resistance. 7 Click Null.

  • Page 56: Table 3-2 Power Dissipation For Various Resistance Ranges

    Measurement Tutorial If power dissipation is a problem, you should select the digital multimeter's next higher measurement range to reduce the errors to acceptable levels. The following table shows several examples: Table 3-2 Power dissipation for various resistance ranges Range Test current power at full scale 100 Ω...

  • Page 57: Ac Measurements

    Measurement Tutorial AC Measurements True RMS AC measurements True RMS responding digital multimeter, like the U2741A, measure the "heating" potential of an applied voltage. Power dissipated in a resistor is proportional to the square of the voltage waveform. This digital multimeter accurately measures true RMS voltage or current, as long as the wave shape contains negligible energy above the instrument's effective bandwidth.
  • Page 58 Measurement Tutorial Table 3-3 Waveform shapes and their parameters Waveform shape Crest factor (CF) AC RMS AC+DC RMS ⎛ ⎞ ------- - ------- - ------- - ------- - × – ⎝ ⎠ The digital multimeter's AC voltage and AC current functions measure the AC- coupled true RMS value, where only the "heating value"...
  • Page 59 Measurement Tutorial For the best AC noise rejection, you should perform the DC measurement at 20 NPLC. True RMS accuracy and high-frequency signal content A common misconception is that “since an AC digital multimeter is true RMS, its sine wave accuracy specifications apply to all waveforms."...

  • Page 60: Other Primary Measurement Functions

    Measurement Tutorial Other Primary Measurement Functions Frequency Measurement Errors The U2741A uses a reciprocal counting technique to measure frequency. This method generates a constant measurement resolution for any input frequency. All frequency counters are susceptible to errors when measuring low- voltage, low- frequency signals.
  • Page 61 Measurement Tutorial Vs = Source Voltage Rs = DUT Source Resistance R = digital multimeter Current Shunt Vb = digital multimeter Burden Voltage Ideal –100% x V Error(%) = Figure 3-3 Burden voltage in current measurement When used in the Agilent USB Modular Instrument Chassis, it is N O T E recommended to use the null function of the U2741A to nullify any offset.

  • Page 62: Other Sources Of Measurement Error

    Measurement Tutorial Other Sources of Measurement Error Loading errors (AC volts) In the AC voltage function, the input of the digital multimeter appears as a 1 MΩ resistance in parallel with 100 pF of capacitance. The cabling that you use to connect signals to the digital multimeter also adds capacitance and loading.
  • Page 63 Measurement Tutorial High-voltage self-heating errors If you apply more than 300 Vrms, self- heating occurs in the digital multimeter's internal signal- conditioning components. These errors are included in the digital multimeter's specifications. Temperature changes inside the digital multimeter due to self- heating may cause additional error on other AC voltage ranges.
  • Page 64 Measurement Tutorial Make sure the digital multimeter and the AC source are connected to the same electrical outlet whenever possible. You should also minimize the area of any ground loops that cannot be avoided. A high- impedance source is more susceptible to noise pickup than a low- impedance source.

  • Page 65: Characteristics And Specifications

    U2741A USB Modular Digital Multimeter User’s Guide Characteristics and Specifications Product Characteristics Product Specifications This chapter describes the U2741A product characteristics and operating specifications. Agilent Technologies...
  • Page 66 Characteristics and Specifications When using the multimeter in an environment where electromagnetic interference or significant electrostatic charge is present, measurement accuracy may be reduced. • The voltage measurement probes are not shielded and can N O T E act as antennas allowing electromagnetic interference to be added to the signal being measured.
  • Page 67 Characteristics and Specifications Product Characteristics REMOTE INTERFACE • Hi-Speed USB 2.0 • USBTMC 488.2 Class device POWER CONSUMPTION • +12 VDC, 2 A maximum • Isolated ELV power source • One year specifications full accuracy from 18 °C to 28 °C at 50% RH OPERATING ENVIRONMENT •...
  • Page 68 Characteristics and Specifications CALIBRATION Calibration interval of one year is highly recommended Measurement Category The U2741A USB modular digital multimeter is intended to be used for measurement in Measurement Category II, 300 V. Measurement Category Definition Measurement CAT I is for measurements performed on circuits not directly connected to MAINS.

  • Page 69: Product Specifications

    Characteristics and Specifications Product Specifications DC specifications Table 4-1 DC accuracy Function Range Input Test current Accuracy Temperature ± impedance /Burden voltage, % of reading + % Coefficient shunt resistance of range) ° C to 18 ° ° C to 55 °...

  • Page 70: Table 4-2 Ac Accuracy For Voltage

    Characteristics and Specifications Specifications are based on 30 minutes warm-up time, NPLC 20 resolution, and calibration temperature 18 °C to 28 °C. For NPLC 0 and 0.025, add 0.01% of range. 120% over range on all ranges except 300 VDC. Input protection up to 300 VDC. Input protected with externally accessible 2 A, 250 V fast blown fuse.

  • Page 71: Table 4-3 Temperature Coefficient For Voltage

    Characteristics and Specifications 300 VDC. Additional error to be added as frequency more than 30 kHz and signal input less than 10% of range. 30 kHz to 100 kHz: 0.003% of full scale per kHz. Input signal has to be more than 50 Vrms. Table 4-3 Temperature coefficient for voltage Range Frequency (Hz)

  • Page 72: Table 4-6 Frequency Accuracy

    Characteristics and Specifications Frequency specifications Table 4-6 Frequency accuracy Functions Range Accuracy Minimum Input Temperature (% of reading + % of Frequency Coefficient (%) range) Frequency 20 to 300 kHz 0.0200 +0.003 1 Hz 0.005 Table 4-7 Frequency sensitivity for AC voltage Functions Input range Minimum sensitivity (RMS sine wave)

  • Page 73: Table 4-8 Temperature Accuracy

    Characteristics and Specifications Temperature specifications Table 4-8 Temperature accuracy Function Thermistor type Range Accuracy Temperature Coefficient Temperature 5 kΩ thermistor –80.0 ° C to 150.0 ° Probe accuracy + 0.2 ° 0.002 ° –112 ° F to 302 ° U2741A User’s Guide...
  • Page 74 Characteristics and Specifications U2741A User’s Guide...
  • Page 75 Index AC accuracy 68, 69 firmware 19, 20 SCPI 28, 30, 32, 33, 34, 35, 36, 37, 38, 39 AC/DC adapter 7 frequency 36, 57 specifications 8, 57, 61, 63, 64, 65 AC components 56 function 60, 61, 68, 70, 71 AC-coupled 31, 56 AC current 2, 33, 34, 56, 61 AC digital multimeter 57...
  • Page 76 U2741A User’s Guide...
  • Page 77 Product specifications and descriptions in this document are subject to change with- out notice. Always refer to Agilent web site for the latest revision. ® Agilent Technologies, Inc. , 2008 - 2012 Fourth Edition, May 4, 2012 U2741-90001 Agilent Technologies...

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