National Instruments NI 4050 User Manual

Computer-Based
Instruments

NI 4050 User Manual

Digital Multimeter Card for PCMCIA

NI 4050 User Manual

March 2000 Edition

Part Number 321427C-01

Worldwide Technical Support and Product Information

www.ni.com

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For further support information, see the Technical Support Resources appendix. To comment on the
documentation, send e-mail to [e-mail]

© Copyright 1999, 2000 National Instruments Corporation. All rights reserved.

Important Information

Warranty

The NI 4050 is warranted against defects in materials and workmanship for a period of one year from the date of shipment, as
evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace equipment that proves to
be defective during the warranty period. This warranty inclu des part s an d la bor.

The media on which you receive National Instruments software are warranted not to fail to execute programming instructions,
due to defects in materials and workmanship, for a period of 90 days from date of sh ipmen t, as evid enced b y receipt s o r other
documentation. National Instruments will, at its op ti on , repair or repl ace soft ware me dia th at do not ex ecu te pr ogram mi ng
instructions if National Instruments receives notice of such defects during the warranty period. National Instruments does not
warrant that the operation of the software shall be uni nterrup ted or error free.

A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the outside of
the package before any equipment will be accepted for warranty work. National Instruments will pay the shipping costs of
returning to the owner parts which are covered by warrant y.

National Instruments believes that the information in this document is accurate. The document has been carefully reviewed
for technical accuracy. In the event that technical or typographical errors exist, National Instruments reserves the right to
make changes to subsequent editions of this document withou t p rio r no ti ce to hold ers o f thi s ed itio n. The read er sh ou ld consul t
National Instruments if errors are suspected. In no even t shall Nati on al Inst rum ents be l iable fo r any dama ges aris in g o ut of
or related to this document or the information contained in it.

XCEPT AS SPECIFIED HEREIN

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WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER

NSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR

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CONSEQUENTIAL DAMAGES, EVEN IF ADVISED OF THE POSSIBILITY THEREOF

apply regardless of the form of action, whether in contract or tort, including negligence. Any action against National Instruments
must be brought within one year after the cause of action accrues. National Instruments shall not be liable for any delay in
performance due to causes beyond its reasonable control. The warranty provided herein does not co ver d amag es, defects,
malfunctions, or service failures caused by ow ner’s fai lu re t o foll ow th e Nation al Inst rum ent s in stal l ation, op erat i on, or
maintenance instructions; owner’s modification of the pro du ct; ow ner’s abus e, m isus e, or negligent acts; and po wer failure or
surges, fire, flood, accident, actions of third parties, or other events outside reasonable control.

ATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND SPECIFICALLY DISCLAIMS ANY

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Copyright

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photocopying, recording, storing in an informatio n retriev al s ystem, o r t ran sl ating , in who le or i n p art, wit ho ut t he prior written
consent of National Instruments Corporation.

USTOMER’S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR

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. This limitation of the liability of National Instruments will

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ATIONAL

Trademarks

CVI™, ComponentWorks™, LabVIEW™, National Instruments™, ni.com™, NI-DAQ™, SCXI™, and VirtualBench™ are trademarks
of National In strum ent s Co rporat ion.

Product and company names mentioned herein are trad emarks o r trad e name s of thei r respect ive compan ies .

WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS

(1) NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL
OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL
COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE
EXPECTED TO CAUSE SIGNIFICANT INJURY TO A HUMAN.

(2) IN ANY APPLICATION, I NCLUDING THE ABOVE , RELIABILITY OF OP ERATION OF THE SOFT WARE PRODUCTS
CAN BE IMPAIRED BY ADVERSE FACTORS, INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL
POWER SUPPLY, COMPUTER HARDWARE MALFUNCTIONS, COMPUTER OPERATING SYSTEM SOFTWARE
FITNESS, FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DE VEL OP AN APPLICAT ION,
INSTALLATION ERRORS, SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS, MALFUNCTIONS OR
FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES, TRANSIENT FAILURES OF ELECTRONIC
SYSTEMS (HARDWARE AND/OR SOFTWARE), UNANTICIPATED USES OR MISUSES, OR ERRORS ON THE PART OF
THE USER OR APPLICATIONS DESIGNER (ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER
COLLECTIVELY TERMED “SYSTEM FAILURES”). ANY APPLICATION WHERE A SYSTEM FAILURE WOULD
CREATE A RISK OF HARM TO PROPERTY OR PERSONS (INCLUDING THE RISK OF BODILY INJURY AND DEATH)
SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRON IC SYSTE M DUE TO THE RISK OF SYSTEM
FAILURE. TO AVOID DAMAGE, INJURY, OR DEATH, THE USER OR APPLICATION DESIGNE R MU ST T AKE
REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES, INCLUDING BUT NOT LIMITED TO
BACK-UP OR SHUT DOWN MECHANISMS. BECAUSE EACH END-USER SYSTEM IS CUSTOMIZED AND DIFFERS
FROM NATIONAL INSTRUMENTS' TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER
MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT
EVALUATED OR CONTEMPLATED BY NATIONAL INSTRUMENTS, THE USER OR A PPLICATION DE SIGNER IS
ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITAB ILITY OF NA TIONAL
INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A
SYSTEM OR APPLICATION, INCLUDING, WITHOUT LIMITATION, THE APPROPRIATE DESIGN, PROCESS AND
SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION.

Compliance

FCC/Canada Radio Frequency Interference Compliance*

Determining FCC Class

The Federal Communications Commission (FCC) has rules to protect wireless communications from interference.
The FCC places digital electronics into two classes. These classes are known as Class A (for use in industrial­commercial locations only) or Class B (for use in residential or commercial locations). Depending on where it is
operated, this product could be subject to restrictions in the FCC rules. (In Canada, the Department of
Communications (DOC), of Industry Canada, regulates wireless interference in much the same way.)

Digital electronics emit weak signals during normal operation that can affect radio, television, or other wireless
products. By examining the product you purchased, you can determine the FCC Class and therefore which of the two
FCC/DOC Warnings apply in the following sections. (Some products may not be labeled at all for FCC; if so, the
reader should then assume these are Class A devices.)

FCC Class A products only display a simple warning statement of one paragraph in length regarding interference and
undesired operation. Most of our products are FCC Class A. The FCC rules have restrictions regarding the locations
where FCC Class A products can be operated.

FCC Class B products display either a FCC ID code, starting with the letters EXN,
or the FCC Class B compliance mark that appears as shown here on the right.

Consult the FCC web site

http://www.fcc.gov for more information.

FCC/DOC Warnings

This equipment generates and uses radio frequency energy and, if not installed and used in strict accordance with the
instructions in this manual and the CE Mark Declaration of Conformity**, may cause interference to radio and
television reception. Classification requirements are the same for the Federal Communications Commission (FCC)
and the Canadian Department of Communications (DOC).

Changes or modifications not expressly approved by National Instruments could void the user’s authority to operate
the equipment under the FCC Rules.

Class A

Federal Communications Commission

This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15
of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the
equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to
radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in
which case the user will be required to correct the interference at his own expense.

Canadian Department of Communications

This Class A digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.
Cet appareil numérique de la classe A respecte toutes les exigences du Règlement sur le matériel brouilleur du

Canada.

Class B

Federal Communications Commission

This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15
of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed
and used in accordance with the instructions, may cause harmful interference to radio communications. However,
there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful
interference to radio or television reception, which can be determined by turning the equipment off and on, the user
is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.

• Increase the separation between the equipment and receiver.

• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.

• Consult the dealer or an experienced radio/TV technician for help.

Canadian Department of Communications

This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations.
Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du

Canada.

European Union - Compliance to EEC Directives

Readers in the EU/EEC/EEA must refer to the Manufacturer's Declaration of Conformity (DoC) for information**
pertaining to the CE Mark compliance scheme. The Manufacturer includes a DoC for most every hardware product
except for those bought for OEMs, if also available from an original manufacturer that also markets in the EU, or
where compliance is not required as for electrically benign apparatus or cables.

* Certain exemptions may apply in the USA, see FCC Rules §15.103 Exempted devices, and §15.105(c).

Also available in sections of CFR 47.

** The CE Mark Declaration of Conformity will contain important supplementary information and instructions

for the user or installer.

Conventions

The following conventions are used in this manual:

» The » symbol leads you through nested menu items and dialog box options

to a final action. The sequence File»Page Setup»Options directs you to
pull down the File menu, select the Page Setup item, and select Options
from the last dialog box.

This icon denotes a note, which alerts you to important information.
This icon denotes a caution, which advises you of precautions to take to

avoid injury, data loss, or a system crash.

bold Bold text denotes items that you must select or click on in the software,

such as menu items and dialog box options. Bold text also denotes
parameter names.

italic Italic text denotes variables, emphasis, a cross reference, or an introduction

to a key concept. This font also denotes text that is a placeholder for a word
or value that you must supply.

monospace Text in this font denotes text or characters that you should enter from the

keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
programs, subprograms, subroutines, device names, functions, operations,
variables, filenames and extensions, and code excerpts.

Contents

Chapter 1
Taking Measurements with the NI 4050

Cable and Probes ...........................................................................................................1-1

Introduction to the VirtualBench-DMM Soft Front Panel.............................................1-3

Use the Soft Front Panel................................................................................................1-5

Measure DC and AC Voltage..........................................................................1-5

Measure 2-Wire Resistance.............................................................................1-6

Measure the Voltage Drop Across a Diode.....................................................1-7

Measure Current..............................................................................................1-8

Measure Temperature......................................................................................1-9

Chapter 2
NI 4050 Operation

Safety Instructions .........................................................................................................2-1

Measurement Fundamentals ...................................................................................... ....2-2

Warm Up.........................................................................................................2-2

Selecting the Resolution..................................................................................2-2

Grounding........................................................................................................2-2

Voltage Measurements ..................................................................................................2-2

DC Voltage......................................................................................................2-2

Input Ranges ................................... .................................. ................2-3

Measurement Considerations............................................................2-3

Input Impedance .................................................................2-3

Thermal EMF .....................................................................2-4

Noise Rejection...................................................................2-4

AC Voltage......................................................................................................2-6

Input Ranges ................................... .................................. ................2-7

Measurement Considerations............................................................2-7

AC Offset Voltage..............................................................2-7

Frequency Response...........................................................2-7

Resistance Measurements..............................................................................................2-8

2-Wire Resistance Measurements ...................................................................2-8

Input Ranges ................................... .................................. ................2-8

Continuity Measurements.............................................................................. ..2-9

Diode Measurements .....................................................................................................2-9

© National Instruments Corporation vii NI 4050 User Manual

Contents

Appendix A
Specifications

Appendix B
Technical Support Resources

Glossary

Index

Figures

Figure 1-1. Installing the NI 4050 and Cables.........................................................1-2

Figure 1-2. NI-DMM Soft Front Panel ....................................................................1-3

Figure 1-3. Digits of Precision.................................................................................1-5

Figure 1-4. Connecting Probes for Voltage Measurement......................................1-6

Figure 1-5. Connections for Resistance Measurement............................................1-7

Figure 1-6. Connecting Signals for Diode Test.......................................................1-7

Figure 1-7. Connections for Current Measurement.................................................1-8

Figure 1-8. Connecting Signals for RTDs and Thermistors....................................1-9

Figure 2-1. Effect of Input Impedance on Signal Measurements............................2-3

Figure 2-2. Normal Mode Measurement Effects.....................................................2-5

Figure 2-3. Common Mode Measurement Effects ..................................................2-6

Figure 2-4. Circuit for 2-Wire Resistance Measurements.......................................2-8

Figure 2-5. Circuit for Diode Measurements...........................................................2-9

NI 4050 User Manual viii www.ni.com

Taking Measurements with
the NI 4050

Thank you for buying a National Instruments 4050 digital multimeter card.
A system based on the NI 4050 offers the flexibility, performance, and
size that makes it ideal for service, repair, and manufacturing as well as
for use in industrial and laboratory environments. The NI 4050, used in
conjunction with your computer, is a versatile, cost-effective platform for
high-resolution measurements.

For the most current versions of manuals and example programs, visit

www.ni.com/instruments for free downloads.

Detailed specifications for the NI 4050 are in Appendix A, Specifications.

Note

Before using any measurement equipment, it is important that you thoroughly

understand the safety instructions for that product. The beginning of Chapter 2, NI 4050

Operation, covers the safety guidelines for your NI 4050.

1

Cable and Probes

The NI 4050 instrument kit contains the NI 4050 accessory cable that
connects the NI 4050 to a pair of test probes with shrouded banana plugs,
which are also included in the kit. Both the NI 4050 accessory cable and the
test probes meet international safety requirements including UL 3111 and
IEC 1010-1 for the full ranges of applications supported by the NI 4050 .
Before using any probes or accessories not supplied by National
Instruments, ensure that they meet applicable safety requirements for the
signal levels you may encounter.

To use the NI 4050 accessory cable and probes with the NI 4050, first
connect the cable to the card as shown in Figure 1-1. The accessory cable
connector is polarized so that it cannot be plugged in incorrectly.

© National Instruments Corporation 1-1 NI 4050 User Manual

Chapter 1 Taking Measurements with the NI 4050

Portable

Computer

PCMCIA Slot

NI 4050

Accessory Cable

Probes

Figure 1-1. Installing the NI 4050 and Cables

The test probes connect to the NI 4050 accessory cable via shrouded
banana jacks. The shrouds around the banana jacks prevent you from
contacting potentially hazardous voltages connected to the test probes.
Y ou can also connect the cable to standard, unshrouded banana jack probes
or accessories; however, use unshrouded probes or accessories only when
the voltages are less than 30 V

Caution To prevent possible safety hazards, the maximum voltage between either of the

inputs and the ground of the computer should never exceed ±250 VDC or 250 V

or 42 V

rms

pk-to-pk

.

.

rms

NI 4050 User Manual 1-2 www.ni.com

Chapter 1 Taking Measurements with the NI 4050

Introduction to the VirtualBench-DMM Soft Front Panel

The following sections explain how to make connections to your NI 4050
and take simple measurements using the VirtualBench-DMM, as shown in
Figure 1-2. To launch the soft front panel, select Start»Programs»
National Instruments DMM»Soft Front Panel.

Figure 1-2.

The following text describes the options available on the soft front panel.
Refer to Help»Online Reference located on the soft front panel for
information on front panel menus.

The range selector determines the range of measurements
V irtualBench-DMM makes. The range differs for each measurement mode.
If the measurement exceeds the range, +OVER or –OVER appears in the
measurement display. Auto selects the range that best matches the input
signal.

The value indicator displays the value measured by your NI 4060
(The value shown is an example only.).

The unit indicator displays the measurement units of the value you are
measuring. The units are expressed as VAC, VDC, mVAC, mVDC, Ω,
kΩ,MΩ, mA, AC, or mA DC. The indicator also displays the digits of
resolution. By clicking on the indicator, you can change the DMM’s
resolution.

NI-DMM Soft Front Panel

© National Instruments Corporation 1-3 NI 4050 User Manual

Chapter 1 Taking Measurements with the NI 4050

The Function selector allows you select a measurement mode. Select
Edit»Settings and click on the tabs for Current and Resistance or
Temperature to control the data type acquired by VirtualBench-DMM.

DC volts measures the DC component of a voltage signal.

AC volts measures the AC component of a voltage signal.

DC current measures the DC component of a current source.

AC current measures the AC component of a current source.

2-wire measures resistance using the 2-wire method.

4-wire measures resistance using the 4-wire method.

Diode measures the voltage drop across a diode. The maximum voltage
VirtualBench-DMM measures is 2 V.

Temperature measures temperature.

The run button starts and stops continuous DMM measurements.

The single button performs a single measurement.

The math buttons allow you to manipulate readings mathematically.

Null starts relative mode. VirtualBench-DMM makes all subsequent
measurements relative to the measurement it makes when you click
on Null.

Max/Min displays the maximum and minimum values that occur after you
start Relative mode.

mX+B enables the mX+B calculation on all readings.
dB compresses a large range of measurements into a much smaller range

by expressing DC or AC voltage in decibels.

dBm shows decibels above or below a 1 mW reference.

NI 4050 User Manual 1-4 www.ni.com

Chapter 1 Taking Measurements with the NI 4050

% selects the percentage calculation. VirtualBench-DMM expresses the
displayed reading as a percent deviation from the reference value entered
in the Math Settings. Refer to Help»Online Reference, Math Settings topic
for more information about dB, dBm, mX+B, and percentage calculations.

The log button enables data logging. To configure the datalog file and log
interval, select Edit»Settings. Refer to Help»Online Reference, Logging
Measurements to Disk topic for more details.

Digits of Precision—A pop-up ring control in the DMM front panel display
allows you to set measurement accuracy to 3 1/2, 4 1/2, or 5 1/2. A larger
value gives greater precision but slower measurement performance. Refer
to Figure 1-3.

Figure 1-3. Digits of Precision

Use the Soft Front Panel

The following sections describe procedures for measuring DC and AC
voltage, resistance, diode, and temperature, using the soft front panel.

Measure DC and AC Voltage

Use the following procedure to measure DC and AC voltage using the soft
front panel:

1. Connect the test probes to voltage signals as shown in Figure 1-4. For
DC voltages, the HI (red) terminal is the positive terminal, and the
LO (black) terminal is negative. For A C voltages, positive and ne gative
terms are irrelevant.

© National Instruments Corporation 1-5 NI 4050 User Manual

Chapter 1 Taking Measurements with the NI 4050

The NI 4050 is protected against damage from voltages within
±250 VDC or 250 V
above these levels to the inputs.

in all ranges. You should never apply voltages

rms

HI

250 V
MAX.

+
–

LO

2. Select the mode you will measure:

•DC Volts

•AC Volts

3. Select the range for your measurement or autoranging:

• DC Volts—± 20 mV, ± 200 mV, ± 2 V, ± 25 V, and ± 250 V

• AC Volts—20 mV

The value indicator displays the voltage measured.

Measure 2-Wire Resistance

Use the following procedure to measure 2-wire resistance using the soft
front panel:

1. Connect the test probes to a resistor as shown in Figure 1-5. To
accurately measure the value of a resistor, mak e sure the resistor is not
connected to any other circuits. Erroneous or misleading readings may
result if the resistor you are measuring is connected to external circuits
that supply voltages or currents or to external circuits that change the
effective resistance of that resistor.

HI

DC Voltage

Source

250 V
MAX.

LO

Figure 1-4. Connecting Probes for Voltage Measurement

, 200 mV

rms

rms

, 2 V

rms

, 25 V

, and 250 V

rms

AC Voltage

Source

rms

NI 4050 User Manual 1-6 www.ni.com