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Summary of content (127 pages)

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Artisan Technology Group is your source for quality new and certified-used/pre-owned equipment • FAST SHIPPING AND DELIVERY • TENS OF THOUSANDS OF IN-STOCK ITEMS • EQUIPMENT DEMOS • HUNDREDS OF MANUFACTURERS SUPPORTED • LEASING/MONTHLY RENTALS • ITAR CERTIFIED SECURE ASSET SOLUTIONS SERVICE CENTER REPAIRS Experienced engineers and technicians on staff at our full-service, in-house repair center WE BUY USED EQUIPMENT Sell your excess, underutilized, and idle used equipment We also offer credit for buy-back
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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 Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.
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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.
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TABLE OF CONTENTS 1.0 INTRODUCTION .................................................................................................................................................7 1.1 SAFETY CONSIDERATIONS ..........................................................................................................................7 1.2 MINIMUM REQUIREMENTS .........................................................................................................................8 1.3 FEATURE SET ...............
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4.1.3 AC Peak-to-Peak and Crest Factor Measurement (SMX2044) .............................................25 4.1.4 AC Median Value Measurement (SMX2044).........................................................................26 4.2 CURRENT MEASUREMENTS ......................................................................................................................26 4.2.1 Improving Current Measurements .........................................................................................26 4.2.
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DMMDelay .....................................................................................................................................57 DMMDisableTrimDAC...................................................................................................................57 DMMDisArmTrigger ......................................................................................................................58 DMMDutyCycleStr ..............................................................................
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DMMSetACCapsDelay ...................................................................................................................93 DMMSetACCapsLevel ....................................................................................................................93 DMMSetACVSource .......................................................................................................................94 DMMSetAutoRange .....................................................................................
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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.
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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.
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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 330 mV 3.3 V 33 V 330 V Full Scale 6 ½ Digits 330.0000 mV 3.300000 V 33.00000 V 330.0000 V Resolution 24 hours 23°C ± 1°C 0.003 + 4.5 µV 0.002 + 10 µV 0.003 + 250 µV 0.004 + 1 mV 100 ηV 1 µV 10 µV 100 µV 90 Days 23°C ± 5°C 0.004 + 5.5 µV 0.0025 + 12 µV 0.004 + 280 µV 0.005 + 1.
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Accuracy ± (% of reading + Volts) [1] Range Frequency 330 mV 10 Hz - 20 Hz 20 Hz - 47 Hz 47 Hz - 10 kHz 10 kHz - 50 kHz 50 kHz - 100 kHz 10 Hz - 20 Hz 20 Hz - 47 Hz 47 Hz - 10 kHz 10 kHz - 50 kHz 50 kHz - 100 kHz 10 Hz - 20 Hz 20 Hz - 47 Hz 47 Hz - 10 kHz 10 kHz - 50 kHz 50 kHz - 100 kHz 10 Hz - 20 Hz 20 Hz - 47 Hz 47 Hz - 10 kHz 10 kHz - 50 kHz 50 kHz - 100 kHz 3.3 V 33 V 250 V 24 hours 23°C ± 1°C 3.0 + 350 µV 0.92 + 150 µV 0.13 + 100 µV 0.55 + 160 µV 5.3 + 350 µV 3.0 + 2 mV 0.93 + 1.3 mV 0.
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2.3.4 AC Median Value Measurement (SMX2044) • • Measures the mid-point between the positive and negative peaks of a repetitive waveform Used to determine the Threshold DAC setting for optimal frequency and timing measurements ACV Range 330 mV 3.3 V 33 V 250 V Lowest specified input voltage (Vp-p) 0.08 V 0.80 V 8V 80 V Full Scale reading ±0.95 V ±9.5 V ±95.0 V ±350.0 V Resolution Typical Accuracy 23°C ± 5°C One Year [1] 1 mV 10 mV 100 mV 1V 2.0% ±17 mV 3% ±160 mV 3% ±1.
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2.5 Resistance Measurements 2.5.1 2-wire and 4-wire Accuracy ± (% of reading + Ω) [1] Range [2] 33 Ω [3] 330 Ω 3.3 kΩ 33 kΩ 330 kΩ 3.3 MΩ 33 MΩ 330 MΩ [3] Full Scale 6 ½ Digits 33.00000 Ω 330.0000 Ω 3.300000 kΩ 33.00000 kΩ 330.0000 kΩ 3.300000 MΩ 33.0000 MΩ 330.00 MΩ Resolution 10 µΩ 100 µΩ 1 mΩ 10 mΩ 100 mΩ 1Ω 100 Ω 10 kΩ Source current 10 mA 1 mA 1 mA 100 µA 10 µA 1 µA 100 nA 10 nA 24 hours 23°C ± 1°C 0.0038 + 1 mΩ 0.0037 + 4.5 mΩ 0.0023 + 28 mΩ 0.0025 + 300 mΩ 0.0055 + 3.2 Ω 0.018 + 40 Ω 0.
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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 11.999 ηF 119.99 ηF 1.
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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] Threshold range (DC level) 330 mV 3.3 V 33 V 250 V -1.0 V to +1.0 V -10.0 V to +10.0 V -100.0 V to 100.0 V -500 V to 500 V Threshold DAC resolution 0.5 mV 5.0 mV 50 mV 500 V Highest allowed input Vp-p Typical one year setting uncertainty 1.900 V 19.00 V 190.0 V 850.0 V 0.
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Polarity Frequency range Resolution Width range Positive or negative pulse widths 1 Hz to 100 kHz 2 µs 2 µs to 1 s Typical Uncertainty 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.
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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 Output Voltage range Typical Current source/sink at 5V output DAC resolution Accuracy 23°C ± 10°C One Year Typical settling time Typical source resistance Closed Loop [1] Open Loop -10.000 V to +10.000 V 5 mA 5 mA 18 bits 12 bits 1.0% ± 35 mV 0.
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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.
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2.13 Other Specifications Temperature Coefficient, All Functions Less than 0.1 x accuracy specification per °C at 23C ± 5°C Reading Rate (user selectable) • 0.5 to 1,000 readings per second (rps) • 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 & LO).
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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.
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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. Figure 3-1. The DMM input connectors.
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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.
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3.6 Using the Control Panel Figure 3-2. The Control Panel for the SMX2044. The three main groups include Measure, Source and Range buttons. The 8 Range buttons are context sensitive such that only “330m, 3.3, 33 and 250 appear 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.
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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 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 range, 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.
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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 Windows 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.
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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.
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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 of the waveform.
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practical, higher current measurements be limited to short time. The lower two ranges of DC current may be effected by relay contamination. If the measurements seem unstable or high, while in IDC measurement, apply 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. 4.2.2 Low Level DC Current Measurements For low level current measurements use the V, Ω+ and V, Ω- terminals.
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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 measurements. 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.
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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 flow through the shunting path. With this “guarding”, the SMX2044 accurately measures the 30 kΩ resistor. 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.
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Figure 4-5. Leakage Test Configuration. Measurement of reverse diode leakage at 3.3V. 4.3.6 Extended Resistance Measurements (SMX2044) The Extended Resistance measurement function operates as complement of the standard resistance measurement. Where the last forces a predefined current, this function forces specified voltage. Where the normal resistance measurement is limited to pre defined current sources, this function has a variable voltage, and it limits current flow by an external sense resistor.
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Figure 4-6. Extended Ohms range. 4.3.7 Effects of Thermo-Voltaic Offset Resistance measurements are sensitive to Thermo-Voltaic (Thermal EMF) errors, which can be caused by poor test leads, relay contacts and other elements in the measurement path. These errors effect all measurement methods, including 2-Wire, 4-Wire, 6-Wire and 3-Wire (guarded 2-Wire ohms). To quantify this error, consider a system in which signals are routed to the DMM via a relay multiplexing system.
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4.3.8 Guarding High Value Resistance Measurements (SMX2044) Measuring high value resistors using the 2-Wire function require special attention. Due to the high impedances involved during such measurements, noise pickup and leakage could be very significant. To improve this type of measurement it is important to use good quality shielded cables with a low leakage dielectric. Even with a good dielectric, if a significant length is involved, an error would result due to leakage. Figure 4.
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A special on board temperature sensor allows monitoring of the DMM’s internal temperature. This provides the means to determine when to run the self-calibration function (S-Cal) for the DMM, as well as predicting the performance of the DMM under different operating conditions. When used properly, this measurement can enhance the accuracy and stability of the DMM. It also allows monitoring of the chassis internal temperature, which is important for checking other instruments. 4.
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4.8 In-Circuit Capacitance Measurement (SMX2044) A second method provided for measuring capacitors is the AC based method. Though not as accurate as the above function, the advantage of this method is that the default stimulus is set at 0.45V peak, which is lower than a semiconductor junction on voltage. It may also be set over a wide range of voltages.
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positive edge, DMMSetBuffTrigRead, and DMMSetTrigRead have a selectable edge parameter. Read about these functions in the Windows Command Language section (5.6) for details. Warning! The DIN connector pins are only protected to a maximum of 30 V with respect to the chassis or any other DMM terminal. Do not apply any voltages greater than 30 V to the DIN connector pins. Violating this limit may result in personal injury and/or permanent damage to the DMM. 4.11.
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Switch Settings S6 S5 S4 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 Trigger Output Routing Disables trigger output PXI_TRIG1 PXI_TRIG2 PXI_TRIG3 PXI_TRIG4 PXI_TRIG5 PXI_TRIG6 PXI_STAR 4.11.4.2 PXI Trigger Inputs The trigger input to the DMM is the wired-ored signal of the trigger input from the DIN-7 connector and the PXI bus trigger. Make sure that no signal is connected to the DIN-7 trigger input while the PXI trigger is in use.
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Figure 4-11. AC coupled timing measurements with Threshold DAC. With the 3.3 ACV range selected, a 10% duty-cycle square wave with 5 V peak-to-peak value, presents a peak-to-peak signal at the internal measuring circuits of –0.5 V to + 4.5 V. The AC Median Value is +2.0 V. By setting the Threshold DAC to the Median value, the internal measuring circuits are properly biased for best performance. Figure 4-12. Comparator and Threshold DAC Settings 4.12.2 Frequency and Period Measurements Both Freq.
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4.12.3 Duty Cycle Measurement Duty Cycle of signals from 1 Hz to 100 kHz can be measured. The minimum positive or negative pulse width of the signal must be at least greater than 2 µs. When measuring duty cycle precisely, the voltage at which the measurement is made is important, due to finite slew rates of the signal. The Threshold voltage can be set for precise control of the level at which duty cycle is measured. For best measurement results, set the Threshold DAC to the Median value.
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4.13 Sourcing Functions (SMX2044) The SMX2044 adds a number of sourcing functions, giving greater versatility for a variety of applications. All of the available sources, VDC, VAC, IDC, are isolated (floating with respect to the chassis). This allows sourcing with a significant common mode voltage as well as the ability to connect several SMX2044 units in parallel for increased DC current, or in series for increased DC voltage.
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4.13.2 AC Voltage Source The AC voltage source is fully isolated. It has two modes of operation: fast settling or closed loop. In the Closedloop mode, the source voltage is monitored, and corrections are made to the composite 16 bit DAC at a rate proportional to the set measurement rate. A 10 rps or lower reading rate is recommended for the Closedloop mode. The Closedloop mode offers the best accuracy.
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Figure 4-16. Sourcing DC current and measuring voltage in the two wire configuration. This function can be used for semiconductor parametric tests. 4.14 Synthesizing Resistance (SMX2044) The SM2044 synthesizes resistance using an iterative method, which requires repeated reading of the DMM to make corrections to the synthesized value. While in synthesizing resistance, the readings return the measured value.
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Selecting the appropriate external resistor is very important. It sets the accuracy and range of the synthesized value. Functions associated with the synthesis of resistance include DMMSetExternalShunt(), which sets the value of the external shunt, and DMMSetResistance(), which control the value to be synthesized. The external resistor should be 100Ω to 10MΩ. Set the measurement to 10 or higher. 20rps is optimal. The Closed loop flag does not have an effect on this function.
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from the computer, whereby the Scanner selects channels from its Scan List table, and the DMM is triggered to take measurements following each channel selection. Figure 4-19. Trigger interfacing to an SMX2040 class of DMMs. 4.15.2 Multiplexing with the SMX2040 DMMs For two wire measurements, the SMX2040 DMM must be connected to the A-Bus or the scanner, or to both, the ABus and C-Bus for 4-Wire measurements (assuming an SM4040 or SM4042 scanner).
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DMMSetBuffTrigRead(nDmm, 4, nReadings, NegEdge) SCANAutoScan(nScan, nSteps) While DMMReady(nDmm) = NO Wend For I = 0 to nReadings -1 while(DMMReadBuffer(nDmm, reading(I)) Next SCANOpenAllChannels(nScan) While SCANReady(nScan) = NO DoEvents Wend ‘ Use 4 settling readings each ‘ Set off AutoScan ‘ wait for the DMM to indicate completion ‘ read values stored in the buffer ‘ Store each reading ‘ Good idea to open all channels when done ‘ Since AutoScan is a polled operation, ' Make sure Scanner is ready There
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5.0 SMX2040 DMM Windows Interface 5.1 Distribution Files The main directory of the distribution diskette contains the Microsoft® Windows™ SMX2040 DMM software. Before installing the DMM or software, read the “Quick Install” page carefully. To install this software, enter the command "A:SETUP" in the "Run Program" menu of the Windows File Manager; or double-click on the SETUP.EXE file name from the File Explorer Tool Manager window.
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SM2044.exe Visual Basic DMM control panel executable Msvcrt.dll System file. Installs in your C:\WINDOWS\SYSTEM directory. Windrvr.vxd Win98/95 Virtual Device Driver. Installs by ‘setup’ in your C:\WINDOWS\SYSTEM\VMM32 directory. Windrvr.sys Win NT Virtual Device Driver. Installs by ‘setup’ in your C:\WINNT\SYSTEM32\DRIVERS directory. Install.doc Installation instructions in MS Word 5.1.1 The SM40CAL.DAT file The SM40CAL.
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the DMM hardware. DMMInit accepts the name and location of the calibration file. A qualified technician may modify individual entries in the calibration file, then reload them using the DMMLoadCalFile command. 5.2 Using the SMX2040 Driver With C++ or Similar Software Install the SM204032.H and UserDMM.H header file in a directory that will be searched by your C/C++ compiler for header files. This header file is known to work with Microsoft Visual C++™.
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* * A simple Windows .EXE example for demonstrating the SMX2040,44 * DMMs using "C" * Sets Function to VDC, Range to 33V, rate to 10rps. * Display five measurements using a Message box. *********************************************************************** * Make sure SM204032.lib is included in the libraries. For Microsoft * Version 4.0 C++ and above, place under 'Source Files' in the * Workspace, along side with Exmp2040.
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The source code file GLOBAL.BAS (in the V_BASIC directory of the distribution diskette) contains the function declarations and the various ranges, rates and other parameters, which are required. These definitions are the duplicates of the “C” header files required to write Visual Basic applications which interact with the driver DLL, along with some global variables required for this particular front-panel application. 5.3.
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After initialization, the Windows DLL default modes and parameters on your DMM are set up as follows: • • • • • • • • • Autoranging: Off Function: DC Volts Range: 330V Relative: Off Synchronized Mode: Off Measurement rate: 10 rps Temperature units are set to °C Offset Ohms: Off AC Caps level: 0.45V Peak. 5.5 Using the SMX2040 DLL with LabWindows/CVI® When using the SMX2040 DLL with LabWindows/CVI, you should read the LabWin.txt file included with the software diskette.
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5.6 Windows Command Language The following section contains detailed descriptions of each function of the Windows command language. Those commands that pertain to only the SM2040 are indicated. Most functions return an error code. The code can either be retrieved as a string using DMMErrString function, or looked up in the SM204032.H header file. The UserDMM.H file contains all the pertinent definitions for the DMM ranges functions etc.
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Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. iSamples int The number of samples the DMM takes following a trigger pulse. This number must be between 1 and 64, inclusive. dThresh double FAR Analog level trigger threshold value Return Value The return value is one of the following constants. Value Meaning DMM_OKAY Operation successfully terminated Negative value Error code. Example double Buffer[64]; DMMArmAnalogTrigger(0,64,1.
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Value Meaning DMM_OKAY Operation successfully terminated Negative Value Error code. Example double Buffer[64]; DMMArmTrigger(0,64); while( ! DMMReady(0)); for(i=0; i < 64 ; i++) Buffer[i] = DMMReadBuffer(0); DMMBurstBuffRead SMX2040 ; SMX2042 ; SMX2044 ; Description Setup the DMM for Triggered operation. #include "sm204032.h" #include "UserDMM.
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DMMBurstBuffRead(0, 4, 50); // 4 settling readings for each // measurement, and take 50 readings // wait for completion while( ! DMMReady(0) ); for(i=0; i < 50 ; i++) // read 64 readings from DMM’s // on-board buffer Buffer[i] = DMMReadBuffer(0); DMMBurstRead SMX2040 ; SMX2042 ; SMX2044 ; Description Setup the DMM for multiple readings operation, sending back measurements as they come. #include "sm204032.h" #include "UserDMM.
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while( ! DMMReadMeasurement(0 , Reading[i]) ); DMMCalibrate SMX2040 ; SMX2042 ; SMX2044 ; Description Internally calibrates the DMM. #include "sm204032.h" int DMMCalibrate(int nDmm) Remarks This function re-calibrates the DMM, and returns it to the current operating mode. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. Return Value The return value is one of the following constants. Value Meaning DMM_OKAY DMM is OK.
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DMM_OKAY Operation successfully completed. Negative Value Error code Example int status = DMMCleanRelay(0, 2, 100); // Shake K2 1000 DMMClearMinMax SMX2040 ; SMX2042 ; SMX2044 ; Description Clears the Min/Max storage. #include "sm204032.h" int DMMGetMin(int nDmm) Remarks This function clears the Min/Max values, and initiates a new Min/Max accumulation. See DMMGetMin for more details. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero.
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Negative Value Example Error code int status = DMMClosePCI(0); DMMDelay SMX2040 ; SMX2042 ; SMX2044 ; Description Wait for a given time. #include "sm204032.h" int DMMDelay(double dTime) Remarks Delay of dTime seconds. dTime must be a positive double number between 0.0 and 100.0 seconds. Parameter Type/Description dTime double Delay time in seconds. Return Value The return value is one of the following constants.
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Negative Value Example Error code DMMDisableTrimDAC(0); // Remove Trim DAC from operation DMMDisArmTrigger SMX2040 ; SMX2042 ; SMX2044 ; Description Abort trigger operation. int DMMDisArmTrigger(int nDmm) Remarks This function sends the DMM a trigger termination command. If the DMM is waiting for a trigger, it will exit the wait mode, and be ready for a new operation. It can be used following an external hardware or analog level trigger arm command (DMMArmAnalogTrigger, DMMArmTrigger, or DMMTrigger ).
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Negative Value Example Error code char cBuf[17]; int status = DMMDutyCycleStr(0, cBuf); DMMErrString SMX2040 ; SMX2042 ; SMX2044 ; Description Return the string describing the error code. #include "sm204032.h" int DMMErrString(int iErrorCode, LPSTR lpszError, int iBuffLength) Remarks This function returns a string containing the error description which corresponds to the iErrorCode. The error string is placed at lpszError. Parameter Type/Description iErrorCode int Error code.
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Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpszReading LPSTR Points to a buffer (at least 16 characters long) to hold the converted result. Return Value Example The return value is one of the following constants. Value Meaning DMM_OKAY Operation successfully completed. DMM_CNT_RNG Frequency counter is over or under range.
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DMMGetACCapsR SMX2040 SMX2042 SMX2044 ; Description Return the resistance component of the last AC Caps measurement. #include "sm204032.h" int DMMGetACCapsRint nDmm, double *lpdResult) Remarks This function retrieves the resistance value from last reading of AC based Capacitance measurement. It performs all scaling and conversion required, and returns the result as a 64-bit double-precision floating-point number in the location pointed to by lpdResult. Returned result is a value in ohms.
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Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. bus int * a pointer to integer at which the bus number is stored (0 to 255) slot int * A pointer to an integer where the slot number is stored (0 to 15) Return Value The return value is one of the following constants. Value Meaning DMM_OKAY Operation was successful.
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int DMMGetdB(int nDmm, double FAR *lpdDev) Remarks This function returns a double floating value that is the dB deviation relative to the reading made just before the relative function was activated. This function is useful in determining measurement errors in dB. It can be used for bandwidth measurements or DC evaluation. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpdDev double FAR * Pointer where the dB value is to be saved.
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Description Retrieve the currently set cold junction temperature. #include "sm204032.h" int DMMGetCJTemp(int nDmm, double *lpdTemp) Remarks Get the currenly set cold juncion temperature. For more details see DMMSetCJTemp() function. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpdTemp double * Points to the location to hold the temperature. Return Value The return value is one of the following constants.
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DMMGetDeviatStr SMX2040 ; SMX2042 ; SMX2044 ; Description Get percent deviation from the reading at the time relative was activated. #include "sm204032.h" int DMMGetDeviatStr(int nDmm, LPCSTR lpszDev) Remarks This function is the same as the DMMGetDeviation(), with the exception that it returns a string. See DMMGetDeviation() for more details. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero.
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Positive value See UserDMM.h for function/range codes. Negative Value Error code Example if(DMMGetFnRange == VDC_300mV) printf("Lowest VDC range selected"); DMMGetFunction SMX2040 ; SMX2042 ; SMX2044 ; Description Get DMM function code. #include "sm204032.h" #include "UserDMM.h" int DMMGetFunction(int nDmm) Remarks This function returns the DMM function code. Parameter Type/Description nDmm int Identifies the DMM nuber. Zero being the first.
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Positive Value Version Negative Value Error code Example firmwarever = DMMGetGrdVer(0); DMMGetHwVer SMX2040 ; SMX2042 ; SMX2044 ; Description Get the hardware version of the DMM. #include "sm204032.h" int DMMGetHwVer(int nDmm) Remarks This function returns the DMM hardware version. A returned value of 0 corresponds to Rev_, 1 corresponds to Rev_A, 2 to Rev_B etc. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero.
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DMM_E_DMM Example Invalid DMM number. int id = DMMGetID(0); DMMGetManDate SMX2040 ; SMX2042 ; SMX2044 ; Description Get Manufacturing date stamp from the DMM hardware #include "sm204032.h" int DMMGetManDate(int nDmm, int *month, int *day, int *year) Remarks This function returns the DMM manufacturing date which is read from the hardware. The month, day and year are returned as integers. This is used to track the DMM to a specific manufacturing date.
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nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpdMax double FAR * Pointer where the Max value is to be saved. Return Value Integer error code.. Value Meaning DMM_OKAY Operation successfully completed. Negative Value Error code Example double FAR Mx; int status = DMMGetMax(0, &Mx); DMMGetMaxStr SMX2040 ; SMX2042 ; SMX2044 ; Description Returns the maximum as a formatted string. #include "sm204032.
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Remarks This function returns a double floating value that is the minimum (of the Min/Max function) value since either a function change, range change or a call to the DMMClearMinMax() function was made. This is only applicable to Primary read functions (those that are read using DMMRead, DMMReadStr or DMMReadNorm). This value is updated every time one of those functions is used. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero.
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Description Get DMM range code. #include "sm204032.h" #include "UserDMM.h" int DMMGetRange(int nDmm) Remarks This function returns the DMM range code. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. Return Value Integer value corresponding to the currently set DMM range, or an error code.
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int DMMGetSourceFreq(int nDmm, double FAR *lpdFreq) Remarks This function returns a double floating value that is the currently set ACV source frequency of the SMX2044. It can be used to display or verify the default frequency of the stimulus for the various Inductance measurement ranges. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpdFreq double FAR * Pointer where the frequency value is to be saved. Return Value Integer error code..
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Remarks This function returns the DMM type. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. Return Value DMM type Integer or an error code. Value Meaning 2040 SMX2040 is at nDmm slot 2042 SMX2042 is at nDmm slot 2044 SMX2044 is at nDmm slot Negative Value Error code Example int type = DMMGetType(0); DMMGetVer SMX2040 ; SMX2044 ; Description Get DMM software driver version. #include "sm204032.
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Description Initialize a DMM. #include "sm204032.h" int DMMInit(int nDmm, LPCSTR lpszCal) Remarks This function must be the first function to be executed. It opens the driver for the specified DMM. The first DMM being 0, the second 1, etc... It also initializes the DMM hardware and does extensive self test to the DMM hardware. It then initializes the software and reads the appropriate calibration record for the respective DMM from the file specified by lpszCal.
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Return Value TRUE, FALSE or an error code. Value Meaning TRUE Autoranging mode is selected. FALSE Autoranging mode is not selected. DMM_E_DMM Invalid DMM number. Example int autorange = DMMIsAutoRange(0); DMMIsInitialized SMX2040 ; SMX2042 ; SMX2044 ; Description Get the status of the DMM. #include "sm204032.h" int DMMIsInitialized(int nDmm) Remarks This function returns the status of the DMM. If TRUE, the DMM has been initialized and is active.
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Return Value Integer TRUE, FALSE or an error code. Value Meaning TRUE Relative mode is selected. FALSE Relative mode is not selected. Negative Value Error code Example int rel = DMMIsRelative(0); DMMLoadCalFile SMX2040 ; SMX2042 ; SMX2044 ; Description Reload calibration record from file. #include "sm204032.h" int DMMLoadCalFile(int nDmm, LPCSTR lpszCal) Remarks This function is provides the capability to reload the calibration record.
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DMMOpenPCI SMX2040 ; SMX2042 ; SMX2044 ; Description Open the PCI bus for the specified DMM. Not for user application. #include "sm204032.h" int DMMOpenPCI(int nDmm) Remarks This function is limited for servicing the DMM. It has no use in normal DMM operation.. See also DMMClosePCI() function. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. Return Value Integer error code. Value Meaning DMM_OKAY Operation successfully completed.
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Return Value Integer error code. Value Meaning DMM_OKAY Operation successfully completed. Negative Value Error code Example int status = DMMOpenCalACCaps(0); DMMOpenTerminalCal SMX2040 SMX2042 SMX2044 ; Description Calibrate the Inductance measurement function with open terminals. #include "sm204032.h" int DMMOpenTerminalCal(int nDmm) Remarks This function characterizes the Inductance measurement path and source, which is required prior to making inductance measurements.
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Remarks This function makes a period measurement and returns the result as a string formatted for printing. The print format is fixed to five digits plus units, e.g., 150.01 ms. See DMMFrequencyStr() for more details. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpszReading LPSTR Points to a buffer (at least 16 characters long) to hold the converted result.
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DMMPolledRead SMX2040 ; SMX2042 ; SMX2044 ; Description Tests the DMM for ready status, and returns the next floating-point reading. #include "sm204032.h" int DMMPolledRead(int nDmm, double FAR *lpdResult) Remarks DMMPolledRead polls the DMM for readiness. If the DMM is not ready it will return FALSE. If the DMM is ready with a new reading it will return TRUE, and the reading will be placed at the location pointed to by lpdResult. See DMMPolledReadCmd for more details.
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Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. Return Value DMM_OKAY if command accepted, else FALSE or an error code. Value Meaning FALSE DMM is busy and can’t execute a polled read command. DMM_OKAY Operation successful.
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Description Return the next floating-point reading from the DMM. #include "sm204032.h" int DMMRead(int nDmm, double FAR *lpdResult) Remarks DMMRead reads the next result from the DMM, performs all scaling and conversion required, and returns the result as a 64-bit double-precision floating-point number in the location pointed to by lpdResult.
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Example double Buffer[10]; int status; DMMArmTrigger(0,10); // Set up for 10 triggered samples while( ! DMMReady(0)); for(i=0; i < 10 ; i++) status = DMMReadBuffer(0, &Buffer[i]); DMMReadBufferStr SMX2040 ; SMX2042 ; SMX2044 ; Description Return the next reading, formatted for printing. #include "sm204032.h" int DMMReadBufferStr(int nDmm, , LPSTR lpszReading) Remarks The same as DMMReadBuffer() except the reading is formatted as a string with units.
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Remarks Read the cold juncion temperature sensor for subsequent thrermocouple measurements. When measuring temperature using thermocouples it is necessary to establish a reference or cold junction temperaturem. This is the temperature at which the themocouple wires are connected to the DMM or to the switching card’s cooper wires. One way to do this is by measuring the cold junction sensor using this function. DMMReadCJTemp() function reads the sensor output voltage (0 to +/-3.
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Return Value Example The return value is one of the following constants. Value Meaning DMM_OKAY Operation successfully completed. Negative Value Error code double CF; int status = DMMReadCrestFactor(0, &CF); DMMReadDutyCycle SMX2040 SMX2042 ; SMX2044 ; Description Return percent duty cycle of ACV signal. #include "sm204032.h" int DMMReadDutyCycle(int nDmm, double FAR *lpdDcy) Remarks This is a Secondary function and the DMM must be in AC measurement function, and a valid range must be set.
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Remarks If frequency counter is not engaged, select it. Make a single frequency measurement, and store the result as a 64-bit double-precision floating-point number in the location pointed to by lpdResult. See DMMFrequencyStr() for more details. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpdResult double FAR * Points to the location to hold the frequency. Return Value The return value is one of the following constants.
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DMMReadInductorQ SMX2040 SMX2042 SMX2044 ; Description Return inductor’s Q value. #include "sm204032.h" int DMMReadInductorQ(int nDmm, double FAR *lpdResult) Remarks This is a Secondary function and the DMM must be in the Inductance measurement function, and a valid inductance value must have been read prior to using this function. Resulting Q is stored as double-precision floating-point number in the location pointed to by lpdResult. Parameter Type/Description nDmm int Identifies the DMM.
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Value Meaning TRUE Measurement was read into *lpdRead FALSE No measurement is available TIMEOUT Communication timeout. No reading available within 9s. OVERRUN Communication overrun. CPU did not keep up with DMM transmission. Other Negative Value Error code. Example double Reading[150]; DMMBurstRead(0, 4, 150); // 4 settel., 150 samples // read 150 measurements for(i=0; i < 150 ; i++) while( DMMReadMeasurement(0 , Reading[i]) == FALSE ); // wait for all measurements to be ready, and read them.
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double floating-point reading. The returned value is corrected for base units. That is, it returns 0.3 for a 300 mV input and 1e6 for 1.0 MOhm. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpdRead double FAR * Pointer to a location where the reading is saved. Return Value Integer value version code or an error code. Value Meaning DMM_E_RANGE Over/Under range error. DMM_E_DMM Invalid DMM number. DMM_OKAY Valid return.
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Description Return the next double floating-point period reading from the DMM. #include "sm204032.h" int DMMReadPeriod(int nDmm, double FAR *lpdResult) Remarks This is a Secondary function and the DMM must be in ACV measurement function, and a valid range must be set It makes a single period measurement, and stores the result as a double-precision floating-point number in the location pointed to by lpdResult. See DMMFrequencyStr() for more details.
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DMM_OKAY Valid return. Negative Value Error code DMM_E_RANGE DMM over range error occurred. Example char cBuf[17]; int status = DMMReadingStr(0, cBuf); DMMReadTotalizer SMX2040 SMX2042 ; SMX2044 ; Description Read the totalized value accumulated by the Totalizer function. #include "sm204032.h" long DMMReadTotalizer(int nDmm) Remarks This function reads the total value accumulated by the Totalizer function. For details see DMMStartTotalize.
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DMMReadWidth SMX2040 SMX2042 ; SMX2044 ; Description Return the positive and negative pulse widths. #include "sm204032.h" int DMMReadWidth(int nDmm, double FAR *lpdPwid, double FAR *lpdNwid) Remarks This is a Secondary function and the DMM must be in ACV measurement function, and a valid range must be set. It returns two parameters: positive and negative pulse widths. These parameters are stored as double-precision floating-point numbers in the location pointed to by lpdPwid and lpdNwid.
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Return Value The return value is one of the following constants. Value Meaning TRUE DMM is done and buffer is ready to be read. FALSE DMM is not ready. Negative Value Error code Example double Buffer[10]; DMMTrigger(0,10); while( ! DMMReady(0) ); for(i=0; i < 10 ; i++) DMMReadBuffer(0, &Buffer[i]); DMMSetACCapsDelay SMX2040 SMX2042 SMX2044 ; Description Set the measurement delay of AC based Capacitance. #include "sm204032.h" #include "UserDMM.
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Remarks This Secondary function sets the AC peak voltage level for the AC based Capacitance measurement function. It actually sets an internal register to ldVols rather than setting the output level itself. This value is used on any of the AC Caps calibration and measurement. Following setting of this function, it is necessary to perform open calibration of the AC Capacitance ranges to be used.
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Value Meaning DMM_OKAY Operation successfully completed. Negative Value Error code Example double reading; int I; DMMSetACVSource(0, 7.0, 1000.0); // source 7V and 1kHz DMMSetSourceMode(0, CLOSED_LOOP); // Closed loop mode for(I=0;I<100;I++) DMMRead(0,&reading); // update 100 times DMMSetAutoRange SMX2040 ; SMX2042 ; SMX2044 ; Description Enable/Disable autorange operation of DMM #include "sm204032.
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Remarks Setup the SMX2040 for external hardware trigger operation. Following reception of this command the DMM enters a wait state. After reception of an external trigger edge of iEdge polarity, the DMM takes iSettle + 1 readings at the set measurement function, range, and reading rate; and stores the last reading in the in an internal buffer. This process is repeated for iSamples. This function is particularly useful in conjunction with a triggering instruments such as the SM4042 relay scanner.
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improve measurement speed. When using this function keep in mind that the accuracy specification provided for capacitance is not guaranteed. Also, modifying these values could have profound efect on the operation of the function. Any time a capacitance range is change, these values are set to the default values. For instance, values of 1 and 3 for iAverage, and iSamples will reduce measurement time on the 12nF range from 0.8s to about 50ms. Parameter Type/Description nDmm int Identifies the DMM.
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DMMSetCompThreshold SMX2040 SMX2044 ; Description Set the Threshold DAC level. #include "sm204032.h" #include "UserDMM.h" int DMMSetCompThreshold(int nDmm, double FAR ldThreshold) Remarks This Secondary function sets the output of the Threshold DAC. To use this function, the DMM must be in AC volts. This function sets the detection threshold of the AC comparator. It is compared by the comparator to the AC coupled input voltage.
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Return Value Integer error code. Value Meaning DMM_OKAY Operation successfully completed. Negative Value Error code Example DMMSetCounterRng(0, COUNTR_320HZ); // Set counter to measure a frequency between 65Hz to 320Hz DMMSetDCISource SMX2040 SMX2042 SMX2044 ; Description Set the DCI source output level. #include "sm204032.h" #include "UserDMM.h" int DMMSetDCISource(int nDmm, double FAR ldAmps) Remarks This Secondary function sets the DC current source to ldAmps.
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Remarks This Secondary function sets the DC voltage source to ldVolts. The DMM must be in VDC_SRC for this function to execute properly. When the DMM is in VDC_SRC operation, and the DMMSetDCVSource is applied, reading the DMM (DMMRead or DMMReadStr) will return the measurement of the output voltage. This function acts on the main 12 bit source DAC. If better accuracy is needed it can be accomplished by selecting the ClosedLoop mode (DMMSetSourceMode).
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Negative Value Example Error code DMMSetExternalShunt(0, 100000.0); // Set shunt to 100kΩ DMMSetFuncRange SMX2040 ; SMX2042 ; SMX2044 ; Description Set the DMM function and range. #include "sm204032.h" #include "UserDMM.h" int DMMSetFuncRange(int nDmm, int nFuncRnge) Remarks This function sets both, the function and range used by the DMM. The table of values is defined as VDC_330mV, VAC_3.3V, IDC_330mA, OHM_4W_330K etc. definitions in the header files.
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Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. nFunc int A pre-defined constant corresponding to the desired function. Return Value The return value is one of the following constants. Value Meaning DMM_OKAY DMM initialized successfully. Negative Value Error code DMM_E_FUNC Invalid DMM function. Example status = DMMSetFunction(0, INDUCTANCE); DMMSetInductFreq SMX2040 SMX2042 SMX2044 ; Description Set the frequency of the Inductance Source.
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Remarks This function enables or disables the Offset Ohms compensation function. The default value is FALSE, or no Offset Ohms compensation. When TRUE the measurement rate is about 1/10th the set value. When enabling this function with the SM2042, a relay is used to perform it and therefore it will click while measuring. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. bState BOOL Determines whether or not Offset Ohms is enabled.
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Set the DMM reading rate. Description #include "sm204032.h" int DMMSetRate(int nDmm, int nRate) This function sets the reading rate used by the DMM. The table of values is defined by the RATE_ values in the header file. It is important to note that the actual range may be effected by the speed of the CPU as well as other processes running in the background, consuming CPU resources. In order to improve the DMM’s measurement rate you may need to do one of the following.
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Description Set the DMM relative reading mode for the present function. #include "sm204032.h" int DMMSetRelative(int nDmm, BOOL bRelative) Remarks This function selects relative or absolute reading mode for the DMM. If the bRelative parameter value is TRUE, the DMM will change to relative reading mode. If FALSE, the DMM will change to absolute reading mode. Caution: Do not select DMMSetRelative when in the autorange mode. Parameter Type/Description nDmm int Identifies the DMM.
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DMMSetResistance SMX2040 SMX2042 SMX2044 ; Description Set the resistance value to be synthesized #include "sm204032.h" int DMMSetResistance(int nDmm, double ldResistance) Remarks This function sets the value of the resistance to be synthesized. The DMM must be in Synthesized Resistance function for this function to be usable. The currently set external shunt resistor value effects the Synthesized Resistance operation. The ldResistance value must be between 10.0 to 0e6 (10MΩ).
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Value Meaning DMM_OKAY Operation successfully completed. Negative Value Error code Example DMMSetFunction(0, RTD); // RTD measurement function DMMSetRange(0, 1 _pt385); // Select RTD DMMSetRTD(0, RTD_4_W, 1000.0); // Set Ro = 1k Ohms DMMSetSensoreParams SMX2040 ; SMX2042 ; SMX2044 ; Description Set the cold junction temperature sensor equation parameters. #include "sm204032.
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Remarks This Secondary function sets the DC and AC voltage sources to either OPEN_LOOP or CLOSED_LOOP. In CLOSED_LOOP the sources use the main 12 bit source DAC. In CLOSED_LOOP the Trim DAC is also used, which augments the 12 bit DAC to produce 16 effective bits. Open loop updates are very quick. In ClosedLoop mode the source level is adjusted every time the DMM is read, making small corrections until the reading is equal to the set voltage.
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Example int status = DMMSetSynchronized(0, FALSE); // Cancell sync. DMMSetTCType SMX2040 ; SMX2042 ; SMX2044 ; Description Set Thermocouple type. #include "sm204032.h" #include "UserDMM.h" int DMMSetTCType(int nDmm, int iType) Remarks This function selects the thermocouple type to be measured and linearized. It must be one of the following: B, E, J, K, N, R, S or T. Parameter Type/Description NDmm int Identifies the DMM. DMMs are numbered starting with zero.
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Return Value The return value is one of the following constants. Value Meaning DMM_OKAY Function succeeded. Negative Value Error code int status = DMMSetTempUnits(0, DEG_F) // set units to °F Example DMMSetTrigRead SMX2040 ; SMX2042 ; SMX2044 ; Description Setup the DMM for mutiple Triggered readings operation. #include "sm204032.h" #include "UserDMM.h" int DMMSetTrigRead(int nDmm, int iSettle, int iSamples, int iEdge) Remarks Setup the SMX2040 for external hardware trigger operation.
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Error code. Negative Value Example double Reading[150]; DMMSetTrigRead(0, 4, 150, 0); // Negative edge, 4 //setteling readings, and 150 samples/triggers for(i=0; i < 150 ; i++) // read buffer while( ! DMMReadMeasurement(0 , Reading[i]) ); DMMSetTrimDAC SMX2040 SMX2042 SMX2044 ; Description Set the Trim DAC level. #include "sm204032.h" #include "UserDMM.h" int DMMSetTrimDAC(int nDmm, int iValue) Remarks This Secondary function sets the Trim DAC to a value between 0 and 100.
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int DMMStartTotalizer(int nDmm, int Edge) Remarks This is a Secondary function and the DMM must be in ACV measurement function, and a valid range must be selected. This function clears the Totalized count, sets the edge sense, and starts the Totalizer. The totalized value can be read during the accumulation period. However, it could affect the count by the interruption. If no reads are performed during accumulation, the input rate can be as high as 45 kHz.
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DMMStopTotalizer SMX2040 SMX2042 ; SMX2044 ; Description Terminate the accumulation process of the Totalizer. #include "sm204032.h" int DMMStopTotalizer(int nDmm) Remarks This function stops the accumulation process. Following this function, the totalized value can be read. For details see DMMStartTotalizer. Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. Return Value Example The return value is one of the following constants.
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DMMTrigger SMX2040 ; SMX2042 ; SMX2044 ; Description Software Trigger the DMM. Take iSamples. #include "sm204032.h" int DMMTrigger(int nDmm, int iSamples) Remarks Following reception of this command, the SMX2040 DMM makes iSamples readings at the currently set function, range and rate, and stores them in an internal buffer. Rate can be set between 10 to 1000 readings per second. No autoranging is allowed for this trigger operation.
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Parameter Type/Description nDmm int Identifies the DMM. DMMs are numbered starting with zero. lpszPos LPSTR Points to a buffer (at least 16 characters long) to hold the positive width result. lpszNeg LPSTR Points to a buffer (at least 16 characters long) to hold the negative width result. Return Value The return value is one of the following constants. Value Meaning DMM_OKAY Valid return.
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6.0 Maintenance Warning These service instructions are for use by qualified personnel only. To avoid electric shock, do not perform any procedures in this section unless you are qualified to do so. This section presents maintenance information for the DMM. Test equipment recommended for calibration is listed below. If the recommended equipment is not available, equipment that meets the indicated minimum specifications may be substituted.
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6.1 Performance Tests This test compares the performance of the SMX2040/44 with the specifications given in Section 2. The test is recommended as an acceptance test when the instrument is first received, and as a verification after performing the calibration procedure. To ensure proper performance, the test must be performed with the SMX2040 installed, with the covers on. The ambient temperature must be between 18°C to 28°C.
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6.3 Resistance Test, 2-wire The following procedure may be used to verify the accuracy of the 2-wire function. 1. If you have not done so, install the SMX2040 and place the covers back on to the computer. Ensure that the computer has been on for at least one-half hour, with the covers on, before conducting this test. 2. Connect the SMX2040 V,Ω + & - terminals to the calibrator HI & LO Outputs. Output 0 Ω from the calibrator. Allow the SMX2040 to settle for a few seconds, and perform the Relative function.
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Table 9-4 Resistance Test, 4-wire Step Range Input Minimum Reading Maximum Reading 1 33 Ω [1] 0Ω -2 mΩ 2 mΩ 1 33 Ω [1] 10 Ω 9.9972 Ω 10.0028 Ω 1 330 Ω 0Ω -6 mΩ 6 mΩ 2 330 Ω 100 Ω 99.987 Ω 100.013 Ω 3 3.3 kΩ 0Ω -33 mΩ 33 mΩ 4 3.3 kΩ 1 kΩ 0.999917 kΩ 1.000083 kΩ 5 33 kΩ 0Ω -350 mΩ 350 mΩ 5 33 kΩ 10 kΩ 9.99905 kΩ 10.00095 kΩ 5 330 kΩ 0Ω -5 Ω 5Ω 6 330 kΩ 100 kΩ 99.986 kΩ 100.014 kΩ [1] SMX2044 only. Note: The use of 4-wire Ohms for resistance values above 300 kΩ is not recommended.
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6.5 AC Voltage Test The following procedure may be used to verify the accuracy of the ACV function: 1. If you have not done so, install the SMX2040 and place the covers back on to the chassis. Ensure that the computer has been on for at least one-half hour, with the covers on, before conducting this test. 2. Apply the following AC voltages to the V, Ω + & - terminals. Check to see that the displayed reading on the SMX2040 is within the indicated readings range. Table 9-5.
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6.6 DC Current Test The following procedure may be used to verify the accuracy of the DCI function: 1. If you have not done so, install the SMX2040 and place the covers back on to the computer. Ensure that the computer has been on for at least one-half hour, with the covers on, before conducting this test. 2. Remove all connections from the SMX2040 inputs. Select the DCI function, Autorange. Allow the SMX2040 to settle for a few seconds, and perform the Relative function. 3.
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6.8 Capacitance Test (SMX2044 only) The following procedure may be used to verify the accuracy of the Capacitance function. 1. If you have not done so, install the DMM and place the covers back on to the computer. Ensure that the computer has been on for at least one-half hour, with the covers on, before conducting this test. 2. Connect the DMM V,Ω + & - terminals to the calibrator HI & LO Outputs. Attach the test leads to the DMM, leaving the other end open circuited.
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6.9 Frequency Counter Test (SMX2044 only) The following procedure may be used to verify the accuracy of the Frequency Counter: 1. If you have not done so, install the DMM and place the covers back on to the computer. Ensure that the computer has been on for at least one-half hour, with the covers on, before conducting this test. 2. Select the ACV function, autorange. Turn freq on. 3. Apply the following AC voltages to the V, Ω + & - terminals.
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6.10 Calibration Each SMX2040 DMM uses its own SM40CAL.DAT calibration file to ensure the accuracy of its functions and ranges. The SM40CAL.DAT file is a text file that contains the DMM identification number, calibration date, and calibration constants for all DMM ranges.
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7.0 Warranty and Service The SMX2040 is warranted for a period of one year from date of purchase. If your unit requires repair or calibration, contact your Signametrics representative. There are no user serviceable parts within the SMX2040. Removal of any of the three external shields will invalidate your warranty. For inwarranty repairs, you must obtain a return authorization from Signametrics prior to returning your unit. 8.
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