Signametrics SMX2040, SMX2042, SMX2044 Operator's Manual

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Operator's Manual

Model SMX2040 6½ Digit Digital Multimeter Model SMX2042 6½ Digit Multi-Function Digital Multimeter Model SMX2044 6½ Digit LCR Sourcing Digital Multimeter

Signametrics Corporation

December, 2004

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CAUTION

In no event shall Signametrics or its Representatives be liable for any consequential damages whatsoever (including, without limitation, damages for loss of business profits, business interruption, loss of business information, or other loss) arising out of the use of or inability to use Signametric's products, even if Signametrics has been advised of the possibility of such damages. Because some states do not allow the exclusion or limitation of liability for consequential damages, the above limitations may not apply to you.

reproduced in any form without the permission of Signametrics Corporation.

Signametrics 2

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TABLE OF CONTENTS

1.0 INTRODUCTION.................................................................................................................................................7

1.1 S

AFETY CONSIDERATIONS

1.2 M

INIMUM REQUIREMENTS

1.3 F

EATURE SET

2.0 SPECIFICATIONS...............................................................................................................................................9

2.1 DC V

2.2 DC C

2.3 AC V

2.4 AC C

2.5 R

2.6 L

2.7 RTD T

2.8 A

2.9 T

2.10 T

2.11 S

2.12 A

2.13 O

OLTAGE MEASUREMENT URRENT MEASUREMENT OLTAGE MEASUREMENTS

2.3.1 AC Voltage True RMS Measurement.......................................................................................9

2.3.2 AC Peak-to-Peak Measurement (SMX2044)..........................................................................10

2.3.3 AC Crest Factor Measurement (SMX2044)...........................................................................10

2.3.4 AC Median Value Measurement (SMX2044).........................................................................11

URRENT MEASUREMENT, TRUE

ESISTANCE MEASUREMENTS

2.5.1 2-wire and 4-wire...................................................................................................................12

2.5.2 6-wire Guarded Resistance Measurement (SMX2044)..........................................................12

EAKAGE MEASUREMENT

DDITIONAL COMPONENT MEASUREMENTS

2.8.1 Diode Characterization .........................................................................................................13

2.8.2 Capacitance Measurement (SMX2042, 44)...........................................................................13

2.8.3 Inductance Measurement (SMX2044)....................................................................................13

2.8.4 In Circuit AC-Based Capacitance Measurements (SM2044) ................................................13

IMING MEASUREMENTS

2.9.1 Threshold DAC ......................................................................................................................14

2.9.2 Frequency and Period Measurement.....................................................................................14

2.9.3 Duty Cycle Measurement.......................................................................................................14

2.9.4 Pulse Width............................................................................................................................14

2.9.5 Totalizer.................................................................................................................................15

RIGGER FUNCTIONS

2.10.1 External Hardware Trigger (at DIN-7 connector) ..............................................................15

2.10.2 PXI Bus Hardware Trigger Inputs (at PXI J2)....................................................................15

2.10.3 PXI Bus Hardware Trigger Output (to PXI J2)...................................................................15

2.10.4 Analog Threshold Trigger....................................................................................................15

OURCE FUNCTIONS

2.11.1 DC Voltage Source ..............................................................................................................16

2.11.2 AC Voltage Source...............................................................................................................16

2.11.3 DC Current Source..............................................................................................................16

CCURACY NOTES THER SPECIFICATIONS

.............................................................................................................................................8

EMPERATURE MEASUREMENT

..........................................................................................................................7

.........................................................................................................................8

...................................................................................................................9

....................................................................................................................9

..................................................................................................................9

RMS..............................................................................................11

..................................................................................................................12

(SMX2044)....................................................................................................12

(SMX2044)...................................................................................12

............................................................................................13

(SMX2042, 44) ................................................................................................14

..............................................................................................................................15

(SMX2044)...........................................................................................................16

................................................................................................................................. 17

.........................................................................................................................18

3.0 GETTING STARTED.........................................................................................................................................19

3.1 S

ETTING THE

3.2 I

NSTALLING THE

3.3 I

NSTALLING THE

3.4 DMM I

3.5 S

TARTING THE CONTROL PANEL

3.6 U

SING THE CONTROL PANEL

4.0 DMM OPERATIONS AND MEASUREMENTS.............................................................................................24

4.1 V

OLTAGE MEASUREMENT

4.1.1 DC Voltage Measurements ....................................................................................................24

4.1.2 True RMS AC Voltage Measurements ...................................................................................25

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DMM..................................................................................................................................19

DMM M DMM

NPUT CONNECTORS

ODULE

.............................................................................................................19

SOFTWARE PACKAGE

......................................................................................................................19

..............................................................................................................21

....................................................................................................................22

........................................................................................................................24

...........................................................................................19

3 Signametrics

4.1.3 AC Peak-to-Peak and Crest Factor Measurement (SMX2044).............................................25

4.1.4 AC Median Value Measurement (SMX2044).........................................................................26

4.2 C

URRENT MEASUREMENTS

4.2.1 Improving Current Measurements.........................................................................................26

4.2.2 Low Level DC Current Measurements...................................................................................27

4.2.3 Extended DC Current Measurements (SM2044) ...................................................................27

4.3 R

ESISTANCE MEASUREMENTS

4.3.1 2-wire Ohm Measurements....................................................................................................27

4.3.2 4-wire Ohm Measurements....................................................................................................27

4.3.3 Using Offset Ohms function...................................................................................................28

4.3.4 6-wire Guarded Resistance Measurement (SMX2044)..........................................................28

4.3.5 Leakage Measurements (SMX2044) ......................................................................................29

4.3.6 Extended Resistance Measurements (SMX2044)...................................................................30

4.3.7 Effects of Thermo-Voltaic Offset ............................................................................................31

4.3.8 Guarding High Value Resistance Measurements (SMX2044)...............................................32

4.4 RTD T

4.5 I

4.6 D

4.7 C

4.8 IN-C

4.9 I

4.10 C

4.11 T

4.12 F

4.13 S

4.14 S

4.15 I

5.1 D

5.2 U

5.3 V

5.4 W

5.5 U

5.6 W

EMPERATURE MEASUREMENT

NTERNAL TEMPERATURE

IODE CHARACTERIZATION APACITANCE MEASUREMENT

IRCUIT CAPACITANCE MEASUREMENT

NDUCTANCE MEASUREMENT

HARACTERISTIC IMPEDANCE MEASUREMENT RIGGER OPERATION

4.11.1 External Hardware Trigger.................................................................................................34

4.11.2 Analog Threshold Trigger....................................................................................................35

4.11.3 Software Issued Triggered Operations................................................................................35

4.11.4 Using the PXI bus Trigger Facilities...................................................................................35

REQUENCY AND TIMING MEASUREMENTS

4.12.1 Threshold DAC ....................................................................................................................36

4.12.2 Frequency and Period Measurements .................................................................................37

4.12.3 Duty Cycle Measurement.....................................................................................................38

4.12.4 Pulse Width..........................................................................................................................38

4.12.5 Totalizer Event Counter.......................................................................................................38

OURCING FUNCTIONS

4.13.1 DC Voltage Source ..............................................................................................................39

4.13.2 AC Voltage Source...............................................................................................................40

4.13.3 DC Current Source..............................................................................................................40

4.13.4 Source Current - Measure Voltage......................................................................................40

YNTHESIZING RESISTANCE

NTERFACING TO THE

4.15.1 Triggering the SMX2040 DMMs .........................................................................................42

4.15.2 Multiplexing with the SMX2040 DMMs...............................................................................43

4.15.3 Interface Commands and Timing .........................................................................................43

ISTRIBUTION FILES

5.1.1 The SM40CAL.DAT file........................................................................................................46

SING THE

ISUAL BASIC FRONT PANEL APPLICATION

INDOWS

SING THE

INDOWS COMMAND LANGUAGE

SMX2040 D

Multiple Card Operations Under Windows....................................................................................47

5.3.1 Visual Basic Simple Application............................................................................................49

DLL D

EFAULT MODES AND PARAMETERS

SMX2040 DLL

DMMArmAnalogTrigger ................................................................................................................51

DMMArmTrigger............................................................................................................................52

DMMBurstBuffRead .......................................................................................................................53

DMMBurstRead..............................................................................................................................54

DMMCalibrate................................................................................................................................55

DMMCleanRelay ............................................................................................................................55

DMMClearMinMax ........................................................................................................................56

DMMClosePCI ...............................................................................................................................56

......................................................................................................................26

..................................................................................................................27

(SMX2044)...................................................................................32

(SMX2044) ....................................................................................................32

.....................................................................................................................33

(SMX2044).............................................................................................33

(SMX2044) ..............................................................................................34

.............................................................................................................................34

(SMX2044).......................................................................................................39

(SMX2044)...............................................................................................41

SMX4032

................................................................................................................................45

RIVER WITH

SERIES RELAY SCANNERS

C++

WITH LABWINDOWS

...........................................................................................................51

Signametrics 4

(SMX2044)..........................................................................34

(SMX2044)..................................................................34

(SMX2042, 44)..................................................................36

...................................................................42

OR SIMILAR SOFTWARE

.............................................................................................48

..............................................................................49

/CVI®.........................................................................50

..........................................................47

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DMMDelay .....................................................................................................................................57

DMMDisableTrimDAC...................................................................................................................57

DMMDisArmTrigger ......................................................................................................................58

DMMDutyCycleStr .........................................................................................................................58

DMMErrString................................................................................................................................59

DMMFrequencyStr.........................................................................................................................59

DMMGetACCapsR .........................................................................................................................61

DMMGetBusInfo.............................................................................................................................61

DMMGetCalDate............................................................................................................................62

DMMGetdB.....................................................................................................................................62

DMMGetdBStr................................................................................................................................63

DMMGetCJTemp............................................................................................................................63

DMMGetDeviation .........................................................................................................................64

DMMGetDeviatStr..........................................................................................................................65

DMMGetFuncRange.......................................................................................................................65

DMMGetFunction...........................................................................................................................66

DMMGetGrdVer.............................................................................................................................66

DMMGetHwVer..............................................................................................................................67

DMMGetID.....................................................................................................................................67

DMMGetManDate..........................................................................................................................68

DMMGetMax..................................................................................................................................68

DMMGetMaxStr .............................................................................................................................69

DMMGetMin...................................................................................................................................69

DMMGetMinStr..............................................................................................................................70

DMMGetRange...............................................................................................................................70

DMMGetRate..................................................................................................................................71

DMMGetSourceFreq ......................................................................................................................71

DMMGetTCType.............................................................................................................................72

DMMGetType .................................................................................................................................72

DMMGetVer ...................................................................................................................................73

DMMInit .........................................................................................................................................73

DMMIsAutoRange ..........................................................................................................................74

DMMIsInitialized............................................................................................................................75

DMMIsRelative...............................................................................................................................75

DMMLoadCalFile...........................................................................................................................76

DMMOpenPCI................................................................................................................................77

DMMOpenCalACCaps...................................................................................................................77

DMMOpenTerminalCal..................................................................................................................78

DMMPeriodStr ...............................................................................................................................78

DMMPolledRead ............................................................................................................................80

DMMPolledReadCmd .....................................................................................................................80

DMMPolledReadStr........................................................................................................................81

DMMRead.......................................................................................................................................81

DMMReadBuffer.............................................................................................................................82

DMMReadBufferStr........................................................................................................................83

DMMReadCJTemp .........................................................................................................................83

DMMReadCrestFactor ...................................................................................................................84

DMMReadDutyCycle......................................................................................................................85

DMMReadFrequency......................................................................................................................85

DMMReadFrequencyStr.................................................................................................................86

DMMReadInductorQ......................................................................................................................87

DMMReadMeasurement.................................................................................................................87

DMMReadMedian........................................................................................................................... 88

DMMReadNorm..............................................................................................................................88

DMMReadPeakToPeak...................................................................................................................89

DMMReadPeriod............................................................................................................................89

DMMReadStr..................................................................................................................................90

DMMReadTotalizer ........................................................................................................................91

DMMReadWidth.............................................................................................................................92

DMMReady.....................................................................................................................................92

5 Signametrics

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DMMSetACCapsDelay ...................................................................................................................93

DMMSetACCapsLevel....................................................................................................................93

DMMSetACVSource .......................................................................................................................94

DMMSetAutoRange ........................................................................................................................95

DMMSetBuffTrigRead ....................................................................................................................95

DMMSetCapsAveSamp...................................................................................................................96

DMMSetCJTemp.............................................................................................................................97

DMMSetCompThreshold ................................................................................................................98

DMMSetCounterRng.......................................................................................................................98

DMMSetDCISource........................................................................................................................99

DMMSetDCVSource.......................................................................................................................99

DMMSetExternalShunt.................................................................................................................100

DMMSetFuncRange......................................................................................................................101

DMMSetFunction..........................................................................................................................101

DMMSetInductFreq......................................................................................................................102

DMMSetOffsetOhms.....................................................................................................................102

DMMSetRange..............................................................................................................................103

DMMSetRate.................................................................................................................................103

DMMSetRelative...........................................................................................................................104

DMMSetResistance.......................................................................................................................106

DMMSetRTD ................................................................................................................................106

DMMSetSensoreParams...............................................................................................................107

DMMSetSourceMode....................................................................................................................107

DMMSetSynchronized...................................................................................................................108

DMMSetTCType ...........................................................................................................................109

DMMSetTempUnits....................................................................................................................... 109

DMMSetTrigRead.........................................................................................................................110

DMMSetTrimDAC ........................................................................................................................111

DMMStartTotalizer.......................................................................................................................111

DMMStopTotalizer .......................................................................................................................113

DMMTerminate.............................................................................................................................113

DMMTrigger.................................................................................................................................114

DMMWidthStr...............................................................................................................................114

SetACCapsFreq.............................................................................................................................115

6.0 MAINTENANCE ..............................................................................................................................................116

6.1 P

ERFORMANCE TESTS

6.2 DC V

6.3 R

6.4 R

6.5 AC V

6.6 DC C

6.7 AC C

6.8 C

6.9 F

6.10 C

7.0 WARRANTY AND SERVICE.........................................................................................................................125

8.0 ACCESSORIES.................................................................................................................................................125

OLTAGE TEST ESISTANCE TEST, 2-WIRE ESISTANCE TEST, 4-WIRE

OLTAGE TEST

URRENT TEST

URRENT TEST APACITANCE TEST

REQUENCY COUNTER TEST

ALIBRATION

............................................................................................................................117

................................................................................................................................117

.....................................................................................................................118

................................................................................................................................120

................................................................................................................................121

(SMX2044

....................................................................................................................................... 124

ONLY

)..................................................................................................122

(SMX2044

ONLY

).....................................................................................123

Signametrics 6

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1.0 Introduction

Congratulations! You have purchased a PXI/CompactPCI Plug-in instrument with analog and systems performance that rivals the best, all-in-one box instruments. The SMX2040 series digital multimeters (DMMs) are easy to setup and use, have sophisticated analog and digital circuitry to provide very repeatable measurements, and are protected to handle any unexpected situations your measurement environment may encounter. To get years of reliable service from these DMMs, please take a few moments and review this manual before installing and using this precision instrument.

This manual describes the SMX2040 and SMX2044 DMMs. Each DMM delivers unmatched breakthrough performance in a PXI and CompactPCI plug-in instrument. With a rich repertoire of functions, the SMX2040 series out performs all other plug-in DMMs, including the trusted Signametrics SM-2020CT, and most brand named bench top units.

Note: In this manual, all references to the "SMX2040" and “DMM” apply to the SMX2040 and SMX2044. Features unique to the SMX2044 will be identified as such.

1.1 Safety Considerations

Safety Considerations

The SMX2040 series of DMMs is capable of measuring up to 300 VDC or 250 VAC across the Volt HI and LO terminals, and can also measure common mode signals that "float" the DMM above EARTH ground by up to 300 VDC or 250 VAC. When making common mode measurements, the majority of the circuits inside the DMM are at the common mode voltage. These voltages can be lethal and can KILL!

During and after installing your DMM, check to see that there are no wires or ribbon cables from your PXI/CompactPCI chassis trapped inside the DMM.

The DMM comes installed with two shields (bottom and top) that must not be removed for performance as well as safety reasons. Removal of these shields and/or improper assembly of the shields can result in

lethal voltages occurring within your chassis. Also make sure the ch assis is 3 U in size.

Warning

Check to see that no loose wires or ribbon cables infringe upon any of the internal circuits of the DMM, as this may apply measurement voltages to your computer, causing electrocution and/or damage to your PXI/CompactPCI chassis !

To avoid shock hazard, install the DMM only into a 3U PXI and CompactPCI chassis that has its power connector connected to a power receptacle with an earth safety ground.

When making any measurements above 50 VDC or 40 VAC, only use Safety Test Leads. Examples of

these are the Signametrics Basic Test Leads and Deluxe Test Leads, offered as an optional accessory with the Signametrics DMMs. Do not use these units in a 6U chassis as an electrocution hazard will be present.

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7 Signametrics

1.2 Minimum Requirements

The SMX2040 series of system DMMs are precision plug-in modules that are compatible with 3U PXI or CompactPCI chassis. The processor type must be a Pentium or equivalent processor running MS Windows. The DMM requires a single PXI or CompactPCI slot. A mouse must be installed when controlling the DMM from the Windows Control Panel. The SMX2040 comes with a Windows' DLL, for operation with Windows' Version 95/98/Me/2000/XP and NT4.0.

1.3 Feature Set

The base unit, the SMX2040, has 6-1/2 digit performance and can be used as a general purpose DMM, giving very accurate and stable readings. The SMX2044 adds to the SMX2040 additional measurement functions not found in other DMMs such as inductance measurement and sourcing capabilities.

SMX2040, 42, 44 6½ Digit DMMs feature table:

Function SMX2040

DMM

DCV 4 ranges, >10 GΩ & 10 MΩ input resistance.

ACV 4 ranges, 1 MΩ input √ √ √ 2-Wire Ohms, six ranges 330 Ω to 33 MΩ √ plus 33 Ω,

4-Wire Ohms, four ranges 330 Ω to 330 kΩ √ plus 33 Ω plus 33 Ω range Offset Ohms DC current, four ranges 3.3 mA to 2.5 A AC current, four ranges 3.3 mA to 2.5 A

Diode V/I characteristics at 100 ηA to 1mA √ Auto range, Relative Min/Max, dB and percent deviation functions On board measurement buffer Measurement rate: 0.2 to 1,000/sec External and threshold trigger Thermocouples

High Dynamic range; +3,300,000 counts

PXI Trigger In/Out Capacitance, seven ranges, 10 nF to 10 mF Temperature (five basic RTD types) Frequency / Period measurement Pulse width, pos./neg., & duty cycle Totalizer/event counter Variable threshold DAC; all timing measure. Peak to Peak, Crest factor, Median Internal DMM temperature sensor Six wire Ohms (with force/sense) Inductance, six ranges 33 µH to 3.3 H DCV source 0 to +/-10.0 V ACV source 0 to 20 V pk-pk, 2 Hz to 75 KHz DC current source, 1 nA to 12.5 mA Leakage measurement Synthesized resistance source Extended Resistance measurements In Circuit Capacitance

√ √ √

√ √ √ √ √ √ √ √ √

√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √

SMX2042

Multi-Function

DMM

330 MΩ

plus 10 mA plus 10 mA

√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √

SMX2044 LCR Sourcing DMM

plus 33 Ω,

330 MΩ

√ √ √ √ √ √ √ √ √

Signametrics 8

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2.0 Specifications

2.1 DC Voltage Measurement

Input Characteristics

• Input Resistance 330 mV & 3.3 V Ranges: >10 GΩ ,

• Input Resistance 33 V & 330 V Ranges: 10.0 MΩ

Accuracy ± (% of reading + Volts) [1]

Range Full Scale

6 ½ Digits

330 mV 330.0000 mV

3.3 V 3.300000 V 33 V 33.00000 V 330 V 330.0000 V

Resolution 24 hours

23°C ± 1°C 100 ηV 0.003 + 4.5 µV 0.004 + 5.5 µV 0.007 + 8 µV 1 µV 0.002 + 10 µV 0.0025 + 12 µV 0.0045 + 17 µV 10 µV 0.003 + 250 µV 0.004 + 280 µV 0.007 + 330 µV 100 µV

0.004 + 1 mV 0.005 + 1.2 mV 0.008 + 1.5 mV

90 Days 23°C ± 5°C

One Year 23°C ± 5°C

[1] With reading rate set to 10 readings per second (rps) or slower, and within one hour of DCV zero, using Relative control.

DCV Noise Rejection Normal Mode Rejection, at 50, 60, or 400 Hz ± 0.5%, is better than 95 dB for reading rates of 10 rps or lower. Common Mode Rejection (with 1 kΩ lead imbalance) is better than 120 dB for these conditions.

2.2 DC Current Measurement

Input Characteristics

• Burden Voltage < 350 mV for all ranges

• Protected with 2.5A fuse ( 5x20mm, 250 V Fast)

Accuracy ± (% of reading + Amps) [1]

Range Full Scale

5 ½ Digits

3.3 mA 3.30000 mA 33 mA 33.0000 mA 330 mA 330.000 mA

2.5 A 2.50000 A

Resolution 24 hours

23°C ± 5°C

10 ηA 0.052 + 200 ηA 0.07 + 350 ηA 0.1 + 400 ηA

100 ηA 0.04 + 1 µA 0.06 + 2 µA 0.1 + 3 µA

1 µA 0.05 + 30 µA 0.055 + 40 µA 0.075 + 60 µA 10 µA 0.55 + 50 µA 0.6 + 200 µA 0.65 + 350 µA

90 Days 23°C ± 5°C

One Year 23°C ± 5°C

[1] With reading rate set to 10 rps or slower, and within one hour of DCI zero, using Relative control.

2.3 AC Voltage Measurements

Input Characteristics

• Input Resistance 1.0 MΩ, shunted by < 100 pF, all ranges

• Crest Factor 3 at Full Scale, increasing to 7 at Lowest Specified Voltage

• AC coupled Specified range: 10 Hz to 100 kHz

• Typical Settling time < 0.5 sec to within 0.1% of final value

2.3.1 AC Voltage True RMS Measurement

Range Full Scale 6 ½ Digits Lowest specified Voltage Resolution

330 mV 330.0000 mV 5 mV [1]

3.3 V 3.300000 V 10 mV 33 V 33.00000 V 100 mV 250 V [2] 250.0000 V 1 V

[1] Between 5 mV and 10 mV, add 100 µV additional error to the accuracy table below. In many computer installations, if the DMM is not near a noisy board, usable voltage measurements of 1 mV can be obtained.

[2] Signal is limited to 8x10 32 kHz, or 8x10

Volt x Hz.

Volt Hz Product. For example, the largest frequency input at 250 V is

9 Signametrics

100 ηV 1 µV 10 µV 100 µV

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Accuracy ± (% of reading + Volts) [1]

Range Frequency 24 hours

23°C ± 1°C

330 mV

3.3 V

33 V

250 V

10 Hz - 20 Hz 20 Hz - 47 Hz 47 Hz - 10 kHz 10 kHz - 50 kHz 50 kHz - 100 kHz 10 Hz - 20 Hz 3.0 + 2 mV 3.1 + 2.2 mV 3.2 + 2.5 mV 20 Hz - 47 Hz 0.93 + 1.3 mV 0.96 + 1.5 mV 1.0 + 1.7 mV 47 Hz - 10 kHz 0.05 + 1 mV 0.055 + 1.1 mV 0.065 + 1.2 mV 10 kHz - 50 kHz 0.62 + 1.2 mV 0.65 + 1.3 mV 0.70 + 1.5 mV 50 kHz - 100 kHz 5.1 + 1.5 mV 5.2 + 1.7 mV 5.3 + 2 mV 10 Hz - 20 Hz 3.0 + 14 mV 3.1 + 16 mV 3.3 + 20 mV 20 Hz - 47 Hz 0.93 + 12 mV 0.96 + 14 mV 1.0 + 16 mV 47 Hz - 10 kHz 0.06 + 10 mV 0.065 + 11 mV 0.073 + 13 mV 10 kHz - 50 kHz 0.31 + 18 mV 0.33 + 21 mV 0.35 + 25 mV 50 kHz - 100 kHz 2.0 + 30 mV 2.2 + 35 mV 2.4 + 40 mV 10 Hz - 20 Hz 3.0 + 140 mV 3.1 + 160 mV 3.3 + 200 mV 20 Hz - 47 Hz 0.93 + 120 mV 0.96 + 130 mV 1.0 + 150 mV 47 Hz - 10 kHz 0.04 + 100 mV 0.045 + 110 mV 0.06 + 130 mV 10 kHz - 50 kHz 0.32 + 150 mV 0.4 + 170 mV 0.45 + 200 mV 50 kHz - 100 kHz 2.5 + 200 mV 2.8 + 240 mV 3.2 + 300 mV

3.0 + 350 µV 3.1 + 380 µV 3.2 + 430 µV

0.92 + 150 µV 0.93 + 170 µV 0.95 + 200 µV

0.13 + 100 µV 0.14 + 110 µV 0.15 + 120 µV

0.55 + 160 µV 0.6 + 200 µV 0.63 + 230 µV

5.3 + 350 µV 5.4 + 370 µV 5.6 + 400 µV

90 Days 23°C ± 5°C

One Year 23°C ± 5°C

ACV Noise Rejection Common Mode rejection, for 50 Hz or 60 Hz with 1 kΩ imbalance in either lead, is better than 60 dB.

2.3.2 AC Peak-to-Peak Measurement (SMX2044)

• Measures the peak-to-peak value of a repetitive waveform

ACV Range

330 mV 0.1 V 1.85 V 1 mV

3.3 V 1.0 V 18.5 V 10 mV 1.4 ±70 mV 33 V 10 V 185.0 V 100 mV 1.0 ±700 mV 250 V 100 V 850.0 V 1 V 1.0 ± 6 V

[1] Specified from 30Hz to 10 kHz. Input signal frequency of 30 Hz to 30 kHz.

Lowest specified

input voltage

(Vp-p)

Full Scale

reading (Vp-p)

Resolution

Typical Accuracy 23°C ± 5°C

One Year [1]

1.5 ±10 mV

2.3.3 AC Crest Factor Measurement (SMX2044)

•

Measures the crest factor (peak / RMS) of a repetitive waveform

ACV Range

330 mV 0.1 V 1.8 V 0.01

3.3 V 1.0 V 18 V 0.01 2.1 ±0.1 33 V 10 V 180 V 0.01 2.0 ±0.1 250 V 100 V 700 V 0.01 2.0 ±0.1

[1] Crest factor measurement requires signal frequency of 30 Hz to 30 kHz.

Lowest specified

input voltage

(Vp-p)

Highest specified input

voltages (Vp-p)

Resolution

Typical Accuracy 23°C ± 5°C

One Year [1]

2.2 ±0.3

Signametrics 10

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2.3.4 AC Median Value Measurement (SMX2044)

• Measures the mid-point between the positive and negativ e peaks of a repetitive waveform

• Used to determine the Threshold DAC setting for optimal frequency and timing measurements

ACV Range

330 mV 0.08 V

3.3 V 0.80 V 33 V 8 V 250 V 80 V

[1] Median measurements require a repetitive signal with frequency range of 30 Hz to 30 KHz.

Lowest specified input

voltage (Vp-p)

Full Scale

reading

±0.95 V

±9.5 V

±95.0 V

±350.0 V

Resolution

1 mV

10 mV 3% ±160 mV

100 mV 3% ±1.4 V

1 V 3% ±12 V

Typical Accuracy 23°C ± 5°C One Year [1]

2.0% ±17 mV

2.4 AC Current Measurement, True RMS

Input Characteristics

• Burden Voltage < 350 mV RMS all Ranges

• Crest Factor 3 at Full Scale, increasing to 7 at Lowest Specified Current

•

Protected with 2.5 A fuse ( 5x20 mm, 250 V Fast)

Range Full Scale 6 1/2 Digits Lowest Specified Current Resolution

3.3 mA 3.300000 mA 33 mA 33.00000 mA 330 mA 330.0000 mA 5 mA 100 nA

2.5 A 2.500000 A 50 mA 1 uA

Accuracy ± (% of reading + Amps)

Range Frequency 24 hours

3.3 mA

33 mA

330 mA

2.5 A

10 Hz - 20 Hz 20 Hz - 47 Hz 47 Hz - 1 kHz 1 kHz - 10 kHz 10 Hz - 20 Hz 20 Hz - 47 Hz 47 Hz - 1 kHz 1 kHz - 10 kHz 10 Hz - 20 Hz 20 Hz - 47 Hz 47 Hz - 1 kHz 1 kHz - 10 kHz 10 Hz - 20 Hz 1.8 + 4 mA 2.5 + 4.5 mA 2.7 + 5 mA 20 Hz - 47 Hz 0.66 + 4 mA 0.8 + 6 mA 0.9 + 6 mA 47 Hz - 1 kHz 0.6 + 3.8mA 0.63 + 3.8 mA 0.65 + 4 mA 1 kHz - 10 kHz 0.6 + 4mA 0.62 + 4.5 mA 0.7 + 5 mA

Note: All AC Current ranges have typical measurement capability to 20 kHz.

50 µA 500 µA

23°C ± 1°C

3.8 + 4 µA 2.7 + 4 µA 2.9 + 4 µA

0.9 + 4 µA 0.9 + 4 µA 1.0 + 4 µA

0.04 + 1.5 µA 0.08 + 3 µA 0.12 + 4 µA

0.12 + 4 µA 0.14 + 4 µA 0.22 + 4 µA

1.8 + 30 µA 2.6 + 30 µA 2.8 + 30 µA

0.6 + 30 µA 0.9 + 30 µA 1.0 + 30 µA

0.07 + 10 µA 0.15 + 20 µA 0.16 + 30 µA

0.21 + 30 µA 0.3 + 40 µA 0.4 + 40 µA

1.8 + 400 µA 2.7 + 400 µA 2.8 + 400 µA

0.6 + 400 µA 0.9 + 400 µA 1.0 + 400 µA

0.1 + 100 µA 0.17 + 180 µA 0.22 + 220 µA

0.3 + 300 µA 0.4 + 350 µA 0.6 + 400 µA

90 Days 23°C ± 10°C

1 nA 10 nA

One Year 23°C ± 10°C

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11 Signametrics

2.5 Resistance Measurements

2.5.1 2-wire and 4-wire

Accuracy ± (% of reading + Ω) [1]

Range [2] Full Scale

6 ½ Digits 33 Ω [3] 33.00000 Ω 10 µΩ 330 Ω 330.0000 Ω 100 µΩ

3.3 kΩ 3.300000 kΩ 1 mΩ 33 kΩ 33.00000 kΩ 10 mΩ 100 µA 0.0025 + 300 mΩ 0.0033 + 330 mΩ 0.006 + 350 mΩ 330 kΩ 330.0000 kΩ 100 mΩ 10 µA 0.0055 + 3.2 Ω 0.007 + 4 Ω 0.009 + 5 Ω

3.3 MΩ 3.300000 MΩ 1 Ω 1 µA 0.018 + 40 Ω 0.03 + 50 Ω 0.04 + 70 Ω 33 MΩ 33.0000 MΩ 100 Ω 330 MΩ [3] 330.00 MΩ 10 kΩ

Resolution Source

current 10 mA 1 mA 1 mA

100 nA 10 nA

24 hours 23°C ± 1°C

0.0038 + 1 mΩ 0.005 + 1.5 mΩ 0.008 + 2 mΩ

0.0037 + 4.5 mΩ 0.0046 + 5 mΩ 0.007 + 6 mΩ

0.0023 + 28 mΩ 0.003 + 32 mΩ 0.005 + 33 mΩ

0.12 + 400 Ω 0.13 + 500 Ω 0.2 + 600 Ω 1 + 50 kΩ 1.4 + 60 kΩ 2.0 + 80 kΩ

90 Days 23°C ± 10°C

One Year 23°C ± 10°C

[1] With reading rate set to 2 rps or slower, and within one hour of Ohms zero, using Relative control. [2] 4-wire ohms is available up to the 330 kΩ range. [3] 33 Ω and 330 MΩ ranges are only available with the SMX2042,44.

2.5.2 6-wire Guarded Resistance Measurement (SMX2044)

Typical additional error contributed by guarding

Range Source current 33 Ω 330 Ω

3.3 kΩ 33 kΩ 100 µA 0.03 + 1 Ω 330 kΩ 10 µA 0.35 + 10 Ω

10 mA 1 mA 1 mA

Accuracy ± (% of reading + Ω)

One Year 23°C ± 5°C [1]

0.3 + 4 mΩ

0.003 + 20 mΩ

0.005 + 100 mΩ

[1] This table should be used in conjunction with the 2-wire and 4-wire table above.

2.6 Leakage Measurement (SMX2044)

Accuracy ± (% of reading + Ω) [1]

Leakage Reading Voltage range

1.00 ηA to 100.00 ηA

100.00 ηA to 1000.00ηA

1000.00 ηA to 3.3 µA

-10 V to +10 V 2 + 350 pA

-9 V to + 9 V

-7 V to + 7 V

One Year 23°C ± 5°C [1]

1.2 + 2 ηA

1.5 + 20 ηA

[1] Error does not include external shunt resistor’s tolerance.

2.7 RTD Temperature Measurement (SMX2044)

RTD Type

pt385, pt3911, pt3916, pt3926 pt385, pt3911, pt3916, pt3926 Cu (Copper)

Cu (Copper)

Ro (Ω)

100, 200 Ω 0.01°C -150 to 650°C ±0.06°C

500, 1 kΩ 0.01°C -150 to 650°C ±0.03°C

Less than 12 Ω 0.01°C -100 to 200°C ±0.18°C for temperatures ≤ 20°C, ±0.05°C

Higher than 90 Ω 0.01°C -100 to 200°C ±0.10°C for temperatures ≤ 20°C, ±0.05°C

[1] With reading rate set to 2 rps or slower, using a 4-wire RTD. Measurement accuracy does not include RTD probe error.

Resolution Temperature

range

Temperature Accuracy 23°C ± 5°C [1]

One Year

otherwise

Signametrics 12

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2.8 Additional Component Measurements

2.8.1 Diode Characterization

• Available DC current values 100 ηA, 1 µA, 10 µA, 100 µA and 1 mA. SMX2042 and SMX2044 add 10

mA. SMX2044 has a variable current from 10 ηA to 12.5 mA using the DCI source.

• Typical Current Value Uncertainty 1%

• Typical Voltage Value Uncertainty 0.02%

•

Maximum diode voltage compliance 4 V

2.8.2 Capacitance Measurement (SMX2042, 44)

Accuracy ± (% of reading + Farads) [1]

Range Full Scale

4 ½ Digits 10 ηF 11.999 ηF 100 ηF 119.99 ηF

1 µF 1.1999 µF

10 µF 11.999 µF 1 ηF

100 µF 119.99 µF 10 ηF

1 mF 1.1999 mF

10 mF 11.999 mF

Resolution One Year

23°C ± 5°C 1 pF 2.1 ± 5 pF 10 pF 1.0

100 pF 1.0

100 ηF

1 µF

1.0

1.2 2

[1] Within one hour of zero, using Relative control. Accuracy is specified for values higher than 5% of the selected

range with the exception of the 10 ηF range, which measures down to 0 pF.

2.8.3 Inductance Measurement (SMX2044)

± (% of reading + inductance) [1]

Range Default

frequency

33 µH

330 µH

3.3 mH 4 kHz 3.3000 mH 33 mH 1.5 kHz 33.000 mH

330 mH 1 kHz 330.00 mH

3.3 H 100 Hz 3.3000 H

75 kHz 50 kHz

Full Scale 4 ½ Digits

33.000 µH 1 ηH 3.0% + 500 ηH

330.00 µH 10 ηH 2.0% + 3 µH

Resolution

100 ηH 1.5% + 25 µH

1 µH 1.5% + 200 µH

10 µH

100 µH

Accuracy 23°C ± 5°C

One Year [2]

2.5 + 3 mH 3 + 35 mH

[1] Within one hour of zero, and Open Terminal Calibration. [2] Accuracy is specified for values greater than 5% of the selected range.

2.8.4 In Circuit AC-Based Capacitance Measurements (SM2044)

Accuracy ± (% of reading + Farads) [1]

Range Full Scale

4 ½ Digits 33 ηF 32.99 ηF 330 ηF 329.9 ηF

3.3 µF 3.299 µF 33 µF 32.99 µF 10 ηF 5% ± 20 ηF

330 µF 329.9 µF 100 ηF 5% ± 1 µF

3.3 mF 3.299 mF

[1] Specified to 2/3 of range (ie. 22ηF on 33nF range). Within one hour from last AC-Caps Open calibration. Add

an error of 50e-6*R*C (%) due to paralled resistance.

Resolution One Year

23°C ± 5°C 10 pF 12% ± 250 pF 100 pF 5% ± 500 pF

1000 pF

1 µF 7% ± 50 µF

4% ± 1 ηF

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13 Signametrics

2.9 Timing Measurements (SMX2042, 44)

2.9.1 Threshold DAC

• The Threshold DAC is used for selecting a detection threshold to give optimal frequency and

timing measurements.

± (% of setting + volts)

Selected VAC

range [1]

330 mV -1.0 V to +1.0 V 0.5 mV 1.900 V 0.2% + 4 mV

3.3 V -10.0 V to +10.0 V 5.0 mV 19.00 V 0.2% + 40 mV 33 V -100.0 V to 100.0 V 50 mV 190.0 V 0.2% + 0.4 V 250 V -500 V to 500 V 500 V 850.0 V 0.2% + 4 V

Threshold range (DC

level)

Threshold

DAC

resolution

Highest allowed input

Vp-p

Typical one year setting

uncertainty

[1] This table should be used in conjunction with the AC volts section above.

2.9.2 Frequency and Period Measurement

ACV Mode

•

Input Impedance 1 MΩ with < 300 pF

Frequency Range 1 Hz - 100 Hz 100 Hz-1 kHz 1 kHz-10 kHz 10 kHz-100 kHz 100 kHz-300 kHz Resolution 1 mHz 10 mHz 100 mHz 1 Hz 1 Hz Uncertainty is ±0.002% of

reading ± adder shown Input Signal Range [1] 10% - 200%

4 mHz 20 mHz 200 mHz 2 Hz 5 Hz

of range

10% - 200%

of range

10% -200%

of range

10% - 200%

of range

45% -200%

of range

[

1] Input RMS voltage required for a valid reading. Do not exceed 250 V RMS input. For example, 10% -200%

of range indicates that in the 330 mVAC range, the input voltage should be 33 mV to 660 mV RMS.

ACI Mode

•

Input Impedance 10 Ω in the 3 mA and 30 mA ranges, 0.1 Ω in the 330 mA and 2.5 A ranges.

Frequency Range 1 Hz - 100 Hz 100 Hz-1 kHz 1 kHz-10 kHz 10 kHz-500 kHz Resolution 1 mHz 10 mHz 100 mHz 1 Hz Uncertainty 0.01% ±4 mHz 0.01% ±20 mHz 0.01% ±200 mHz 0.01% ±2 Hz

Input Signal Range,

3.3 mA, 330mA Ranges [1] Input Signal Range, 33 mA, 2.5A ranges

[1] Input current required to give a valid reading. For example, 10% -500% of range indicates that in the 3.3 mA range, the input current should be 0.33 mA to 16.5 mA.

10% -500%

of range

50% -100%

of range

10% - 500%

of range

50% - 100%

of range

10% -500%

of range

50% - 100%

of range

10% - 500%

50% - 100%

of range

2.9.3 Duty Cycle Measurement

Frequency Range 1 Hz to 100 Hz 100 Hz to 1 kHz 1 kHz to 10 kHz 10 kHz to 100 kHz

Resolution 0.02% 0.2% 2% 20%

Typical Uncertainty is ±0.03% of reading ± adder shown Full scale reading 100.00 % 100.00 % 100.00 % 100.00 %

0.03% 0.3% 3% 20%

2.9.4 Pulse Width

Signametrics 14

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± (% of reading + sec)

Polarity Frequency range Resolution Width range Typical

Uncertainty Positive or negative pulse widths

1 Hz to 100 kHz

2 µs 2 µs to 1 s 0.01 +/- 4 µs

2.9.5 Totalizer

• Active edge polarity: Positive or negative transition

• Maximum count: 10^9

•

Allowed rate: 1 to 30,000 events per second Uses Threshold DAC

•

2.10 Trigger Functions

2.10.1 External Hardware Trigger (at DIN-7 connector)

Trigger Input voltage level range High: +3V to +15V, Low: -15V to +0.8V Ttrigger High current drive Min. 1mA, Max 10mA (TTL or CMOS logic level) Timing Characteristics Trigger occurs within 2/Reading rate Trigger Activation Positive or Negative edge depending on trigger

command.

Internal Reading Buffer Up to 1,000 readings/sec into 64 locations reading buffer

Isolation of trigger input ±50 V from analog DMM inputs, and from computer

chassis earth ground.

2.10.2 PXI Bus Hardware Trigger Inputs (at PXI J2)

Trigger Input TTL or CMOS positive pulse Trigger Pulse Width Internal Reading Buffer up to 1,000 readings/sec into 64 readings buffer Selectable lines PXI_TRIG1,2,3,4,5,6,7 and PXI_STAR Isolation from DMM inputs ±330 V from any of the DMM 4 main inputs terminals

Minimum 250µS

2.10.3 PXI Bus Hardware Trigger Output (to PXI J2)

Trigger Output TTL or CMOS negative pulse. Positive edge = ready Trigger Pulse Width Activity A single pulse is issued for each A/D conversion (at 10

Selectable lines PXI_TRIG1,2,3,4,5,6 and PXI_STAR Isolation from DMM inputs ±330 V from any of the DMM 4 main inputs terminals

Approximately 140µS

or higher measurement rate)

2.10.4 Analog Threshold Trigger

• Captures up to 64 readings

•

Reading rate: 10 rps or higher

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15 Signametrics

2.11 Source Functions (SMX2044)

• Isolated to 300 V DC from the Chassis

• Current can be paralleled with multiple SMX2044s

•

Voltage can be put in series with multiple SMX2044s

2.11.1 DC Voltage Source

Parameter Closed Loop [1] Open Loop Output Voltage range -10.000 V to +10.000 V Typical Current source/sink at 5V output 5 mA 5 mA DAC resolution 18 bits 12 bits Accuracy 23°C ± 10°C One Year 0.015% ± 350 µV Typical settling time 3 S (rate set to 2/s) 1 mS Typical source resistance

250 Ω

1.0% ± 35 mV

[1] 10 rps or lower measurement rate is required for the closed loop mode.

2.11.2 AC Voltage Source

Parameter Closed Loop [1] Open Loop Output Voltage, sine wave 50mV to 7.1 V RMS (0.14 to 20.0V peak-to-peak) DAC resolution 16 bits 12 bits Typical Current Drive at 3.5V RMS 3.5 mA RMS Accuracy 18°C to 28°C One Year Typical settling time (f-out > 40 Hz) 10 s (rate set to 2 rps) 1.5 s Typical source resistance Frequency range / resolution 2 Hz to 75 kHz / 2 Hz Frequency stability 100 ppm ± 1 Hz

[1] 5 rps or lower measurement rate is required for the closed loop mode.

ACV spec ± 2 mV ACV spec + 0.8% ± 20 mV

250 Ω

2.11.3 DC Current Source

Range Compliance Voltage Resolution [1] Minimum level

1.25 µA

12.5 µA 125 µA

1.25 mA 4.2 V

12.5 mA 1.5 V

4.2 V 500 pA

4.2 V

5 ηA 10 ηA 1% + 100 ηA 50 ηA 100 ηA 1% + 500 ηA 500 ηA 1 µA 1% + 5 µA 5 µA 10 µA 1% + 50 µA

1 ηA 1% + 10 ηA

[1] Resolution without Trim DAC. The use of the Trim DAC can improve the resolution by a factor of 10, but it has to be set separately since it is not calibrated.

Accuracy 23°C ± 10°C One Year

Signametrics 16

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2.12 Accuracy Notes

Important All accuracy specifications for DCV, Resistance, DCI, ACV, and ACI apply for the time periods shown in the respective specification tables. To meet these specifications, the System Calibration function must be performed once a day. System Calibration is a simple software operation that takes a few seconds. Do it by executing the DMMCalibrate() command, or selecting S-Cal in the control panel.

All three products are capable of continuous measurement as well as data transfer rates of up to 1,000 readings per second (rps). To achieve the 6-1/2 digit resolution, the DMM should be operated at 5 rps or slower. The maximum reading rate for 5-1/2 digits is 30 rps.

Accuracy vs. Reading Rates All of the above specifications apply to reading rates of 2 rps or lower. For higher reading rates, increase the noise floor for DCV, Resistance, and DCI by the square root of the increase in reading rate from 2 rps. For example, the noise floor for the 3.3 VDC range is 8 µV at 5 rps. At 20 readings per second, or 10x the reading rate, the noise increases by the square root of 10, or 3.16 times. The noise, then, at 20 readings per second is ± 25 µV.

The noise characteristics for the AC functions increases by the same number as the DC functions. For example, the noise floor for the 3.3 VAC, 20 rps, will have digit rattle of 8.7 mV vs. 2.75 mV at 2 rps.

Reading Rates vs. Noise Rejection The best AC (50 Hz, 60 Hz or 400 Hz) power line rejection is obtained at reading rates that are whole number divisions greater than 1 of the line frequency, as shown in the following table. For best AC line rejection you should use the reading rates checked. It is important to follow this table. Always use the lowest checked rate that is practical for the application.

Reading Rate (rps) Power Line frequency 50 Hz 60 Hz 400 Hz

0.1

0.2

0.5 1 2 5 10 15 √ 20 25 30 √ 40 50 60 √ 80 100 200 400

√ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √ √

√ √

√

√ √

√ √ √ √

Reading Rates vs. Digits of Resolution For reading rates of 10 readings per second (rps) and slower, the DMM has 6 ½ digits of resolution. For reading rates from 10 rps to 30 rps, the DMM has 5 ½ digits of resolution.

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17 Signametrics

2.13 Other Specifications

Temperature Coefficient, All Functions Less than 0.1 x accuracy specification per °C at

Reading Rate

• Up to 10 rps, 6 ½ digits

• Up to 30 rps, 5 ½ digits

Hardware Interface Single 3U PXI or CompactPCI slot

Overload Protection (voltage inputs) 330 VDC, 250 VAC

Isolation 330 VDC, 250 VAC from Earth Ground

Maximum Input (Volt x Hertz) 8x106 Volt x Hz normal mode input (across Voltage HI &

1x106 Volt x Hz Common Mode input (from Voltage HI or

Safety Designed to IEC 1010-1, Installation Category II.

Calibration Calibrations are performed by Signametrics in a computer

Temperature Range -10°C to 70°C, operating

-65°C to +85°C, storage

Size

DMM Internal Temperature ±2°C Measurement (SMX2042, 44)

Power +5 volts, 300 mA maximum

Note: Signametrics reserves the right to make changes in materials, specifications, product functionality, or accessories without notice.

(user selectable)

• 0.5 to 1,000 readings per second (rps)

23C ± 5°C

LO).

LO relative to Earth Ground).

with a 3°C internal temperature rise. All calibration constants are stored in a text file.

7” X 3.5” (Standard PXI/CompactPCI 3U format)

Accessories

Several accessories are available for the SMX2040 DMMs, which can be purchased directly from Signametrics, or one of its approved distributors or representatives. These are some of the accessrories avaialble:

• DMM probes SM-PRB ($15.70)

• DMM probe kit SM-PRK ($38.50)

• Delux probe kit SM-PRD ($95.00).

• Shielded SMT Tweezer Probes SM-PRSMT ($24.90).

• Multi Stacking Double Banana shielded cable 36” SM-CBL36 ($39.00).

• Multi Stacking Double Banana shielded cable 48” SM-CBL48 ($43.00).

• Mini DIN Trigger, 6-Wire Ohms connector SM2040-CON7 ($14.00).

• LabView VI’s library SM204x.llb ($99.00).

Signametrics 18

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3.0 Getting Started

After unpacking the DMM, please inspect for any shipping damage that may have occurred, and report any claims to your transportation carrier.

The DMM is shipped with the Digital Multimeter module; three floppy disks containing the various software panels and drivers plus the calibration data specific for the unit, and this Operator's manual.

3.1 Setting the DMM

The SMX2040 series DMMs are PXI/CompactPCI Plug&Play devices and do not require any switch settings, or any other adjustments to the DMM prior to installation. The on ly sw itches are the PXI trigger input and output selection switches, capable of selecting one of the PXI triggers and PXI Start Trigger.

The SM40CAL.DAT file supplied with your DMM has a unique calibration record for that DMM (See "Calibration" at the end of this manual.) When using multiple DMMs in the same chassis, the SM40CAL.DAT file must have a calibration record for each DMM. Append the unique calibration records of each DMM into one SM40CAL.DAT file using a text editor such as Notepad. The defalut location for the SM40CAL.DAT file is at the root directory C:\.

3.2 Installing the DMM Module

Warning

To avoid shock hazard, install the DMM only into a chassis that has its power line connector connected to an AC receptacle with an Earth Safety ground.

After installation, check to see that no loose wires or ribbon cables infringe upon any of the internal circuits of the DMM, as this may apply measurement voltages to your chassis, causing personal injury and/or damage to your equipment!

This module is designed for 3U PXI and CompactPCI chassis. To prevent shock hazard do not plug it into other format chassis such as 6U without making shure that all sides of the DMM are covered.

Caution: Only install the DMM module with the power to the chassis turned OFF!

Use extreme care when plugging the DMM module(s) into a PXI or CompactPCI chassis. If possible, choose an empty slot away from any high-speed boards (e.g. CPU or other noisy modules) or the power supply. Please be patient during the installation process! Due to it’s shielding it is a tight fit. Watch for any interference b etween the module and the chassis. Gently push the DMM into the chassis, making shure the handle is correctly located. Once in, lock it in with the handle and tighten th e top and bottom screws to secure it into the chassis. Be patient!

3.3 Installing the DMM software package

To install the DMM, turn off the PXI/CompactPCI chassis, plug in the DMM into the PXI/CompcatPCI chassis, preferably away from the CPU or any other noisy card, than turn on the power. The first time you power up your computer with the DMM installed, your Windows system will detect the new DMM and will open the “New Hardware found” wizard. It will prompt you for a driver. Insert Disk1 which contains the necessary driver.

To complete the installation, run the ‘SETUP’ program provided on the Diks1. This takes care of all installation and registration requirements of the software. If you are installing the DMM on a computer that had an SMX2040 series install in it, you should first uninstall the old software. For a clean reintallation remove all INF files containing reference to the Signametrics DMM. Dependig on operatin g system, these files will be located at Windows\inf, Windows\inf\other or WINNT\inf. The files will be named Oemx.INF where x is 0,1,2,… and/or SIGNAMETRICSSMX2040.INF. If present, these files will prevent “Found New Hardware” wizard from detecting the new DMM. Also, make sure you backup and remove the old calibration record (C:\SM40CAL.DAT).

3.4 DMM Input Connectors

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19 Signametrics

Before using the DMM, please take a few moments and review this section to understand where the voltage, current, or resistance and other inputs and outputs should be applied. This section contains important information

concerning voltage and current limits. Do not exceed these limits, as personal injury or damage to the instrument, your chassis or application may result.

F input con

igure 3-1. The DMM nectors.

V + This is the positive termin ode and inductance measurements, and for

, Ω al for all Volts, 2WΩ, capacitance, di sourcing of VDC, VAC and IDC. ents. The maximum input across V, Ω + and V, Ω - is 300 VDC or 250 V ode. When in the sourcing mode, the maximum

ed before damage occ

urs is 100 volts. input allow

WΩ measuremIt is also the Source HI for 4

mAC when in the measuring

V, Ω - This is the negative terminal for all Volts, 2WΩ, capacitance diode and inductance measurements, and or sourcing of VDC, VAC and IDC. It is also the Source LO for 4WΩ. Do not float this terminal or any other

DMM terminal more than 300 VDC or 250 VAC above Earth Ground. (Also, see Trig, 6W Guard below.)

I + This is the positive terminal for all Current measurements. It is also the Sense HI for 4WΩ measurements and

6WΩ guarded measurements. The maximum input across I, 4WΩ + and I, 4WΩ - is 2.5 A. Do not apply more than 5 V peak across these two terminals!

I – This is the negative terminal for all Current measurements. In the Current modes, it is protected with a 2.5 A, 250 V Fast Blow fuse (5 x 20 mm). It is also the Sense LO for 4WΩ measurements and 6WΩ guarded measurements. V, Ω - and I, 4WΩ - should never have more than 5 V peak across them.

TRIG GUARD Both the Trigger and Guard functions use the DIN-7 connector. This group of pins include the

positive and negative hardware trigger input lines and the two SMX2044 Guarded Measurement Force and Sense signals. The external trigger initiates reading(s) into the onboard buffer, and the 6W guard signals facilitate in-

Signametrics 20

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circuit resistor measurements by means of isolating a loading node. The DIN-7 plug can be ordered from Signametrics and is available at many electronic hardware distributors. The connector is generically referred to as a mini DIN-7 male. The trigger signal should be in the range of 3 V to 12 V peak. The two 6W guard signals should never have more than 5 V peak across them.

Warning! The DIN connector pins are protected to a maximum of 35 V with respect to the chassis and any other DMM terminal. Do not apply any voltages greater than 35 V to the DIN connector pins. Violating this limit may result in personal injury and/or permanent damage to the DMM.

DIN-7, Pin number Function 7 External Trigger, Positive terminal 4 External Trigger, Negative terminal 1 Guard Source (SMX2044) 6 Guard Sense (SMX2044)

DIN-7 Connector Pin Description, view from bracket side.

.5 Starting the Control Panel 3

You can verify the installation and gain familiarity with the DMM by exercising its measurement functions using the Windows based Control Panel. To run the control panel, double click the “SMX2044.EXE”. If you do not hear the relays click, it is most likely due to an installation error. Another possible sour ce for an error is that the SM40CAL.DAT file does not correspond to the installed DMM.

The Control Panel is operated with a mouse. All functions are accessed using the left mouse button. When the DMM is operated at very slow reading rates, you may have to hold down the left mouse button longer than usual for the program to acknowledge the mouse click.

Note: The SMX2040 front panel powers up in DCV, 2 readings per second, 330 V range. If the DMM is operated in Autorange, with an open input, you may hear the SMX2040 relays clicking every few seconds, as a range change occurs. This is perfectly normal with ultra high impedance DMMs such as the SMX2040. This phenomenon is caused by the virtually infinite input impedance of the 330 mV and 3.3 V DCV ranges. On these ranges, an open input will read whatever charge is associated with the signal conditioning of the DMM. As this electrical charge changes, the SMX2040 will change ranges, causing the relay clicking. This is normal.

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21 Signametrics

3.6 Using the Control Panel

Figure 3-2. The Control Panel for the SMX2044. The three main groups include Measure, Source and

ange buttons. The 8 Range buttons are context sensitive such that only “330m, 3.3, 33 and 250 appear R when in AC Voltage Functions, “3.3m 33m 330m 2.5” appear when in Current Functions, etc.

Note: All of the controls described below correspond to their respective software function, which can be invoked within your control software or as objects in a visual programming environment. Using the software command language of the SMX2040 provides powerful capabilities. Some composite functions are not included in the control panel above.

DC/AC This function switches between DC and AC. This is applicable for the following DMM functions: Voltage, Current, and Voltage-Source. If Voltage-Source is the function presently in use, the Source control under the Tools menu can be used to set frequency and amplitude in ACV, and amplitude only in DCV and DCI.

Relative This is the Relative function. When activated, the last reading is stored and subtracted from all subsequent readings. This is a very important function when making low level DCV measurements, or in 2WΩ. For example, when using 2WΩ, you can null out lead resistance by shorting the leads together and clicking on Relative. When making low level DC voltage measurements (e.g., in the µV region), first apply a copper short to the V,Ω + & - input terminals, allow the reading to stabilize for a few seconds, and click on Relative. This will correct for any offsets internal to the SMX2040. The Relative button can also be used in the Percent and dB deviation displays

hown below), which are activated using the

The Min/Max box can be used to analyze variations in terms of Min, Max, Percent and dBV. This display can be activated by selecting the menue. For instance, testing a circuit bandwidth with an input of 1V RMS, activate t Relative function with the frequency set to 100Hz, than sweep gradually the frequency and monitor the percent deviation as well as the dBV error and capture any response anomalies with the Min/Max display. The left display indicates peaking of 2.468% (0.21 dBV) and maximum

10.79mV from the reference at 100Hz.

Tools in the top menu.

Min/Max/Deviation from the Tools

peaking in the response of +56.24mV and a notch of –

Rate Box Controls the SMX2040 reading rate. 0.1 rps to 1,000 rps can be set. As measurement rate increases, so does the measurement noise. For best accuracy set to the lowest rate acceptable for the application. Also consider the line frequency (50/60 Hz) of operation when setting reading rates, as certain reading rates have more noise rejection at either 50 or 60 Hz. (See “Specifications” for details.) Generally, set the measurement rate to as low a rate as practical for the application. When measuring RMS values, th ere is no point setting the measurement rate to a value higher than 5 rps since the RMS circuitry has a settling time that is over a second. The capacitance and inductance functions are not affected by rate setting.

Note on Measurement Rate: All three products are capable of continuous measurement as well as data transfer rates of up to 1,000 rps. To achieve the 6-1/2 digit resolution and accuracy, the DMM should be operated at 10 rps or slower. The maximum reading rate for 5-1/2 digits is 30 rps.

Signametrics 22

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Range Can be set to AutoRange or manual by clicking on the appropriate range in the lower part of the Windows

pprop

panel. Autoranging is best used for bench top application and is not recommended for an automated test application due to the uncertainty of the DMM ran ge, as well as the extra time for range changes. Locking a range is highly recommended when operating in an automated test system, especially to speed up measurements. Another reason to lock a range is to control the input impedance in DCV. The 330 mV and 3.3 V ranges have virtually infinite input impedance, while the 33 V and 330 V ranges have 10 MΩ input impedance.

S_Cal This function is the System Calibration that corrects for internal gain, scale factor and zero errors. The DMM does this by alternatively selecting its local DC reference and a zero input. It is required at least once every day to meet the SMX2040 accuracy specifications. We recommend that you also perform this function whenever the external environment changes (e.g. the temperature in your work environment changes by more than 5°C, or the SMX2044 on board temperature sensor indicates more than a 5°C change). This function takes less than a few seconds to perform. Disconnect all leads to the DMM before doing this operation. Keep in mind that this is not a substitute for periodic calibration, which must be performed with external standards.

ClosedLoop This check box selection is used in conjunction with the AC and DC Voltage-Source functions of the SMX2044. When checked, the DMM monitors the output level and continuously applies corrections to the output level. When not checked, the DMM is a 12 bit source vs. 16 bits in the ClosedLoop mode.

OpenCal This check box selection is used in conjunction with inductance measurement. It is necessary to perform Open Terminal Calibration using this control, prior to measuring inductance. This function characterizes both the internal DMM circuitry as well as the probe cables. To perform OpenCal, attach the probe cables to the DMM, leaving the other end of the probe cables open circuited. Then, activate the OpenCal button.

Sync With this check box selection is active, the DMM measurements are internally synchronized, which reduces the measurement rate, but allows full scale input swings to be settled in single measurement.

Sources Panel There are three function buttons in the Source group (SMX2044 only). The V, I, LEAK buttons

select one of three source functions, Voltage (DC and AC), IDC and Leakage. The Sources Panel is automatically enabled when one of the source functions is enabled. It can also be invoked using the Sources Panel selection under the

Tools menu. This panel allows the entry of values for all of the source functions, including Leakage.

The V-OUT Scroll bar and Text box are used to set the Voltage for DC and AC Volts as well as for Leakage. When sourcing ACV, the voltage is in RMS and the FREQ. Scroll bar and Text box control the frequency of the source. It is also used to control inductance frequency. When sourcing DC current, use the I-OUT set of controls. When measuring timing or freqeuncy the THRESH set of controls is used for comperator threshold. All of the source controls are context sensitive and will be enabled when

riate.

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23 Signametrics

4.0 DMM Operations and Measurements

Most of the SMX2040 measurement functions are accessible from the Windows Control Panel (Figure above). All of the functions are included in the Wind ows DLL driver library. To gain familiarity with the SMX2040 series DMMs, run the Windows ‘SETUP.EXE’ to install the software, then run the DMM, as described in the previous section. This section describes in detail the DMM’s operation and measurement practices for best performance.

4.1 Voltage Measurement

Measures from 0.1 µV to 300 VDC or 250 VAC. Use the V, Ω + and V, Ω - terminals, being certain to always leave the I+, I- and DIN-7 terminals disconnected. Use the AC/DC button on the Control Panel to switch between AC and DC.

Making Voltage Measurements is straightforward. The following tips will allow you to make the most accurate voltage measurements.

4.1.1 DC Voltage Measurements

When making very low level DCV measurements (<100 µV), you should first short the DMM with a copper wire shorting plug across the V, Ω + and V, Ω - terminals and perform the Relative function to eliminate zero errors before making your measurements. A common source of error can come from your test leads, which can introduce several µVolts of error due to thermal voltages. To minimize thermal voltaic effects after handling the test leads, you should wait a few seconds before making measurements. Signametrics offers several high quality probes that are optimal for low level measurements.

Signametrics 24

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4.1.2 True RMS AC Voltage Measurements

ACV is specified for signals greater than 1mV, from 10 Hz to 100 kHz. The ACV function is AC coupled, and measures the true RMS value of the waveform. As with virtually all true-RMS measuring meters, the SMX2040 may not read a perfect zero with a shorted input. This is normal.

ACV measurements, if possible, should have the NEUTRAL or GROUND attached to the SMX2040 V,Ω - terminal. See Figure 4-1, below. This prevents any “Common Mode” problems from occurring (Common Mode refers to floating the SMX2040 V,Ω LO above Earth Ground.) Common Mode problems can result in noisy readings, or even cause the computer to hang-up under high V x Hz input conditions. In many systems, grounding the source to be measured at Earth Ground (being certain to avoid any ground loops) can give better results.

Figure 4-1. Make Voltage measurements with the source ground attached to the SMX2040 V,Ω - to minimize “Common Mode” measurement problems.

4.1.3 AC Peak-to-Peak and Crest Factor Measurement (SMX2044)

Measurement of Peak-to-Peak, Crest Factor and AC Median values requires a repetitive waveform between 30 Hz and 100 kHz. The DMM must be in AC voltage measurement mode, with the appropriate range selected. Knowing the Peak-to-Peak value of the waveform is useful for setting the Threshold DA C (d escrib ed below). This latter function is a composite function, and may take over 10 seconds to perform.

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25 Signametrics

4.1.4 AC Median Value Measurement (SMX2044)

To better understand the usage of this function, you should note that the DMM makes all AC voltage measurements through an internal DC blocking capacitor. The voltage is thus “AC coupled” to the DMM. The measurement of the Median value of the AC voltage is a DC measurement performed on the AC coupled input signal. This measurement returns the mid-point between the positive and negative peak o f the waveform. The Median value is used for setting the comparator threshold level for best counter sensitivity and noise immunity. (It is difficult to measure the frequency of a low duty cycle, low amplitude AC signal since there is DC shift at the comparator input due to the internal AC coupling. The SMX2044 overcome this problem by allowing you to set the comparator threshold level). For further information on the usage of AC Median value and Peak-to-Peak measurements, and the Threshold DAC, see the “Frequency and Timing Measurements” section below.

This function requires a repetitive signal. The DMM must be in AC voltage measurement mode, with the appropriate range selected.

4.2 Current Measurements

The SMX2040, 42, 44 measure from 10 ηA to 2.5 A. Use the I, 4WΩ terminals, being certain to always leave the V,Ω + & - terminals disconnected. Use the AC/DC button to switch between AC and DC.

The Current functions are protected with a 2.5 A, 250 V fuse.

Warning! Applying voltages > 35 V to the I+, I- inputs can cause personal injury and/or damage to your DMM and computer! Think before applying any inputs to these terminals!

When making sensitive DC current measurements, be sure to use the Relative function to zero out any residual errors of the SMX2040. This is easily accomplished by opening all inputs to the SMX2040 and performing Relative in the appropriate DCI range.

Figure 4-2. AC and DC Current measurement connection.

4.2.1 Improving Current Measurements

hen making sensitive DC current measurements, be sure to use the Relative function to zero out any residual

erro M and performing

rs of the SMX2040. This is easily accomplished by disconnecting all terminals to the DM

Relative in the appropriate DCI range. Using the S-Cal (DMMCalibrate()) prior to activating Relative will improve accuracy further. Although the SMX2040 family is designed to withstand up-to 2.5A indefinitely, be awa that excessive heat may be generated when measuring higher AC or DC currents. If allowed to rise this heat may adversely effect subsequent measurements. In consideration with this effect, it is reco

Signametrics 26

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mmended that whenever

ractical, higher current measurements be limited to short time. The lower two ranges of DC current may be

p effected by relay contamination. If the measurements between 20mA and 50mA DC to the current terminals and clean the K2 relay using the DMMCleanRelay(0, 2,

200). Repeat this until the measurements are stable.

seem unstable or high, while in IDC measurement, apply

4.2.2 Low Level DC Curr

or low level current measurements use the

SMX urement function is facilitated by the DMM’s low

2040 can measure very low currents. This hidden meas

leakage front-end and a virtual 1

this VDC range, it is practical to measure down to 20pA. The maximum current

easured has more to do with the user’s acceptable burden voltage (the voltage drop across the

0.0MΩ input resistance. With a typical offset error of less than 100µV in

ent Measurements

V, Ω+ and V, Ω- terminals. Using the 33V DCV range, the

value that can be

0.0MΩ shunt) then the DMM limitations. Assuming a maximum burden voltage of 3.3V the maximum current level is 330ηA. This range is well within leakage measurements required in most semiconductor testing. It is also a very quite and stable. Since the DMM does not have an explicit low current function, it i

0.0M

necessary to calculate the current, which is equal to the measured voltage divided by

Ω.

4.2.3 Extended DC Current Measurements (SM2044)

The leakage measurement function can also be used to measure low-level currents. Using a relatively high value shunt resistor and setting the leakage test voltage to 0V allows measurements of super low level currents, without any burden voltage. Read the leakage current section of the manual for more details.

4.3 Resistance Measurements

esistance is measured with one of eight (six in the SMX2040) precision current sources, with the DMM displaying

R the resistance value. Most measurements can be made in the 2-wire mode. 4-wire ohms is used to make precision low resistance measurements. All resistan errors. See section section 4.3.5 for details.

ce measurement modes are susceptible to Thermo-Voltaic (Thermal EMF)

4.3.1 2-wire Ohm Measurements

The DMM measure using 330Ω to 33 MΩ ranges. The SMX2042 and SMX2044 add 33 Ω and 330 MΩ ranges. Use the V,Ω+, V,Ω- terminals, being certain to always disconnect the I+, I- terminals.

Most resistance measurements can be made using the simple 2-wire e

nd of the resistor, and the V,Ω- to the other end. If the resistor to be measured is less than 30 kΩ, you should null out any lead resistance errors by first touching the V,Ω+ and V,Ω- test leads together and then performing a Relative function. If making measurements above 300 kΩ, you should use shielded or twisted leads to minimize noise pickup. This is especially true for measurements above 1 MΩ.

You may also want to control the Ohms current used in making resistance measurements. (See the Specifications section, "Resistance, 2-wire and 4-wire", for a table of resistance range vs. current level.) All of the Ohms ranges of the SMX2040 have enough current and voltage compliance to turn on diode junctions. For characterizing semiconductor part types, use the Diode measurement function. To avoid turning on a semiconductor junction, you may need to select a higher range (lower current). When checking semiconductor junctions, the DMM displays a resistance value linearly related to the voltage across the junction .

For applications requiring resistance measurements higher than 330 MΩ, the Extended Resistance Measurement method is available with the SMX2044.

Ohms method. Simply connect V,Ω+ to one

4.3.2 4-wire Ohm Measurements

4-wire Ohms measurements are advantageous for making measurements below 330 kΩ, eliminating lead resistance errors. The Voltage (V,Ω) Input terminals serve as the current “Source” (i.e. they provide the current stimulus in the ohms measurement), and the I, 4WΩ Input terminals are the “Sense” inputs. The Source + and Sense + leads are connected to one side of the resistor, and the Source - and Sense - leads are connected to the other side. Both Sense leads should be closest to the body of the resistor. See Figure 4-3.

4-wire Ohm makes very repeatable low ohms measurements, from 100 µΩ (10 µΩ for SMX2042, 44) to 330 kΩ. It is not not recommended to us 4WΩ when making measurements above 100 kΩ, although 4-wire ohms is allowed

27 Signametrics

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up to 330 kΩ. 4-wire measurements are disabled above 330 kΩ since the extra set of leads can actually degrade the accuracy, due to additional leakage and noise paths.

Figure 4-3. The I- and I+ sense leads should be closest to the body of the resistor when making 4WΩ mea

surements.

4.3.3 Using Offset Ohms function

Inadvertent parasitic leakage currents, Thermo voltaic voltages and other voltages in series can effect resistance measurements with the measured resistance. This is common particularly when doing in-circuit measurements, and it could manifest as having a significantly different readings when changing Ohms ranges. In addition to eliminating such error, this function can also be used to measure internal resistance of low value voltage sources such as variou batteries and supplies. Use the normal 2-Wire or 4-Awire Ohms connection, and set the Offset Ohms to the enabled or disabled state using the DMMSetOffsetOhms() function. When set TRUE, the measurement rate will be about

of the set DMM rate. Both negative and positive polarity voltages can be handled as long as the total voltage

1/10 including the Ohms source current times the measured resistance plus the parasitic voltage are less than 3.7V. To calculate this voltage consult the specification part of this manual for the specific current for each Ohms range. Th default value of this function is FAL

ue to it’s different hardware, the SMX2042 is different in that one of the DMM relays is being used to perform

D this

operation, which can be heard.

SE. This function is implemented for the SMX2040, SMX2042 and SMX2044.

4.3.4 6-wire Guarded Resistance Measurement (SMX2044)

The SMX2044 provides a guarded 6-wire resistance measurement method. It is used to make resistance measurements when the resistor-under-test has other shunting paths that can cause inaccurate readings. This method isolates the resistor-under-test by maintaining a guard voltage at a user-defined node. The gu

e shunting of the DMM Ohms source current from the resistor-under-test to other components. The Guard Source

th and Guard Sense terminals are provided at pins 1 and 6 of the DIN connector respectively.

Warning! The DIN connector pins are only protected to a maximum of 35 V with

ny other DMM terminal. Do not apply any voltages greater than 35 V to the DIN connector pins. Violating

a this limit may result in personal injury and/or permanent damage to the DMM.

Example: Assume a 30 kΩ resistor is in parallel with two resistors, a 510 Ω and a 220 Ω, connected in series. In normal resistance measurement, the 510 Ω and 220 Ω would shunt most of the DMM Ohms source current, causing

Signametrics 28

ard voltage prevents

respect to the chassis or

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an inaccurate reading. By sensing the voltage at the top of the 30 kΩ, and then applying this same voltage to the junction of the 510 Ω and 220 Ω, there is no current

MX2044 accurately measures the 30 kΩ resistor.

flow through the shunting path. With this “guarding”, the

Figure 4-4. 6-wire guarded in-circuit ohms measurement configuration.

The current compliance of the Guard Force is limited to a maximum of 20 mA and is short-circuit protected. The resistor connected between the low of the 4-wire terminals and the guard point is the burden resistor, or R

: R

the limited guard source current, this resistor can not be lower than R ohms source current for the selected range, and R Ω range and measuring a 300 Ω resistor imposes a limit on R resistor, R

, does not have this limit imposed on it, selecting the measurement polarity, Ra can become R

is the resistance being measured. For exa

bmin

of at least 15 Ω or greater. Since the top burden

versa. For cases where this limit is a problem, simply set the measurement polarity such that R

= Io * Rx / 0.02, where Io is the

bmin

mple, selecting the 330

is the higher of the

. Due to

and vise

two burden resistors.

To measure values greater than 330 kΩ using the 6-wire guarded method, it is necessary to select the 2-wire ohms function, and maintain the 6-wire connection as in Figure 4-4 above.

4.3.5 Leakage Measurements (SMX2044)

The SMX2044 measures leakage currents by applying a DC voltage across the load and measuring the current through it. An external shunt resistor, R voltage at which leakage is measured is set using DMMSetDCVSource(), and the value of R

DMMSetExternalShunt() (the default is 1 MΩ). Leakage current is read using DMMRead(), DMMReadStr() or DMMReadNorm() functions. Depending on the value of R

between –10V and +10 V. Specifically; the maximum voltage is limited to 10.2V – (R

) measurement range and accuracy depends on the shunt resistor being used. The range is set as 3.3V/RS, with

resolution of 10uV/R

. For instance, with RS equal to 1MΩ, the maximum leakage current is 3.3uA with resolution

of 10pA, and at full scale the maximum test voltage is 6.7V. The test voltage is adjusted whenever a measurement is made. Therefore, if the leakage current being measured varies significantly over time, it is best to repeatedly read the DMM allowing the DMM to make corrections to the internal source voltage, compensating for drop across the shunt. Performing open terminal calibration will imrove the accuracy of this function (use

DMMOpenTerminalCal()

with all terminals open). Refer to Figures 4-5. See section 2.6 for specifics. Setting

the source to closed loop mode, DMMSetSourceMode(), will improve the accuracy of the test voltage.

is used to sense the current. See Figures 4-5 for connection. The DC

is entered using

and the leakage current, the test voltage may be set

* IL). The leakage current

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29 Signametrics

+ 97 hidden pages

Signametrics SMX2040, SMX2042, SMX2044 Operator's Manual

Specifications and Main Features

Frequently Asked Questions

User Manual