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National Instruments SCXI-1141 User Manual

Eight-channel lowpass filter modules
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SCXI
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SCXI-1141/1142/1143
User Manual
Eight-Channel Lowpass Filter Modules
SCXI-1141/1142/1143 User Manual
October 2001 Edition
Part Number 320748C-01

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Summary of Contents for National Instruments SCXI-1141

  • Page 1 SCXI ™ SCXI-1141/1142/1143 User Manual Eight-Channel Lowpass Filter Modules SCXI-1141/1142/1143 User Manual October 2001 Edition Part Number 320748C-01...
  • Page 2 Sweden 08 587 895 00, Switzerland 056 200 51 51, Taiwan 02 2528 7227, United Kingdom 01635 523545 For further support information, see the Technical Support Resources appendix. To comment on the documentation, send e-mail to techpubs@ni.com. © 1994, 2001 National Instruments Corporation. All rights reserved.
  • Page 3 The reader should consult National Instruments if errors are suspected. In no event shall National Instruments be liable for any damages arising out of or related to this document or the information contained in it.
  • Page 4 Classification requirements are the same for the Federal Communications Commission (FCC) and the Canadian Department of Communications (DOC). Changes or modifications not expressly approved by National Instruments could void the user’s authority to operate the equipment under the FCC Rules.
  • Page 5 Canadian Department of Communications This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations. Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada. Compliance to EU Directives Readers in the European Union (EU) must refer to the Manufacturer’s Declaration of Conformity (DoC) for information** pertaining to the CE Mark compliance scheme.

  • Page 6: Table Of Contents

    Safety Information ......................2-2 Installing Your Software....................2-4 Installing the SCXI-1141/1142/1143 Module ...............2-4 Installing the SCXI-1141/1142/1143 Module in an SCXI Chassis....2-4 Connecting the SCXI-1141/1142/1143 Module to a DAQ Device for Multiplexed Scanning in an SCXI Chassis..........2-6 Connecting the SCXI-1141/1142/1143 Module to a DAQ Device for Multiplexed Scanning in a PXI Combination Chassis......2-7...
  • Page 7 Performance of the SCXI-1141/1142/1143 Module Filters......4-7 Magnitude Response................. 4-7 Phase Response................. 4-9 Setting the Cutoff Frequency............4-13 Using the SCXI-1141/1142/1143 Module as an Antialiasing Filter....4-14 Using the External Clock Input............... 4-15 DC-Correction Circuitry and Overload Recovery .......... 4-17 Filter Bypass Mode ..................4-17 Rear Connector Analog Outputs ...................
  • Page 8 Phase Error of the SCXI-1141/1142/1143 Module.......4-11 Figure 4-8. Group Delay of the SCXI-1141/1142/1143 Module......4-11 Figure 4-9. Unit Step Response of the SCXI-1141/1142/1143 Module ....4-12 Figure 4-10. Aliasing of an Input Signal with a Frequency 0.8 Times the Sample Rate..................4-14 Tables Table 3-1.

  • Page 9: About This Manual

    About This Manual This manual describes the electrical and mechanical aspects of the SCXI-1141/1142/1143 module and explains how to install and use it. The SCXI-1141/1142/1143 module is an National Instruments (NI) Signal Conditioning eXtensions for Instrumentation (SCXI) Series module. The SCXI-1141/1142/1143 module has eight configurable channels of differential amplification and filtering.

  • Page 10: Conventions

    This font is also used for the proper names of disk drives, paths, directories, programs, subprograms, subroutines, device names, functions, operations, variables, filenames and extensions, and code excerpts. SCXI-1141/1142/1143 SCXI-1141/1142/1143 refers to the SCXI-1141 module, the SCXI-1142 module, and the SCXI-1143 module. SCXI-1141/1142/1143 User Manual ni.com...

  • Page 11: Introduction

    The SCXI-1141 has elliptic filters; the SCXI-1142, Bessel filters; and the SCXI-1143, Butterworth filters. You can use the SCXI-1141/1142/1143 module for lowpass filtering and antialiasing applications as well as for general-purpose signal amplification and filtering. The SCXI-1141/1142/1143 module works with National Instruments E Series MIO DAQ devices and with the SCXI-1200 data acquisition and control module.

  • Page 12: What You Need To Get Started

    Chapter 1 Introduction What You Need to Get Started To set up and use the SCXI-1141/1142/1143 module, you need the following: ❑ SCXI-1141/1142/1143 module ❑ SCXI-1141/1142/1143 User Manual ❑ NI-DAQ – Version 6.5.1 or later for the SCXI-1141 module –...

  • Page 13: Installing And Configuring The Scxi-1141/1142/1143 Module

    This chapter describes how to install the SCXI-1141/1142/1143 module into an SCXI chassis and how to configure the software. Unpacking the SCXI-1141/1142/1143 Module The SCXI-1141/1142/1143 module is shipped in an antistatic package to prevent electrostatic damage to the module. Electrostatic discharge can damage several components on the module.

  • Page 14: Safety Information

    Misuse of the product can result in a hazard. You can compromise the safety protection built into the product if the product is damaged in any way. If the product is damaged, return it to National Instruments for repair. Do not substitute parts or modify the product except as described in this document.
  • Page 15 Chapter 2 Installing and Configuring the SCXI-1141/1142/1143 Module Operate this product only at or below the installation category stated in Appendix A, Specifications. The following is a description of installation categories: • Installation category I is for measurements performed on circuits not directly connected to MAINS .

  • Page 16: Installing Your Software

    Note It is important to install the NI-DAQ driver software before installing the SCXI-1141/1142/1143 module to ensure that the module is properly detected. Installing the SCXI-1141/1142/1143 Module The following section describes how to install the SCXI-1141/1142/1143 module for use with an SCXI chassis and National Instruments DAQ devices.

  • Page 17: Figure 2-1. Installing The Scxi-1141/1142/1143 Module

    Turn off the SCXI chassis. Caution Do not insert the SCXI-1141/1142/1143 module into a chassis that is turned on. Insert the SCXI-1141/1142/1143 module into an open slot in the SCXI chassis. Gently guide the module into the slot guides and push it to the back of the slot until the front face of the module is flush with the front of the chassis.

  • Page 18: Connecting The Scxi-1141/1142/1143 Module To A Daq Device For Multiplexed Scanning In An Scxi Chassis

    To finish installing the SCXI-1141/1142/1143 module, complete the following section that is appropriate for your application. Connecting the SCXI-1141/1142/1143 Module to a DAQ Device for Multiplexed Scanning in an SCXI Chassis Use this configuration to multiplex all eight input channels and the cold-junction compensation (CJC) channel of the SCXI-1141/1142/1143 module into a single channel of the DAQ device.

  • Page 19: Connecting The Scxi-1141/1142/1143 Module To A Daq Device For Multiplexed Scanning In A Pxi Combination Chassis

    Multiplexed Scanning in a PXI Combination Chassis Use this configuration to multiplex all eight channels of the SCXI-1141/1142/1143 module into a single channel of the DAQ device in a combination PXI chassis. You need the following items for this installation: •...

  • Page 20: Connecting The Scxi-1141/1142/1143 Module To A Daq Device For Parallel Scanning

    Installing and Configuring the SCXI-1141/1142/1143 Module chassis according to their installation instructions. To connect the SCXI-1141/1142/1143 module with a DAQ device in a PXI combination chassis for multiplexed scanning, follow these steps: No cables are required for this connection if the National Instruments PXI DAQ device is installed in the right-most slot.
  • Page 21 Connect the cable to the back of the cable adapter and ensure that the cable fits securely. Connect the other end of the cable to the National Instruments DAQ device that you want to use to access the SCXI-1141/1142/1143 module in parallel mode.

  • Page 22: Configuring And Testing The Scxi-1141/1142/1143 Module

    Installing and Configuring the SCXI-1141/1142/1143 Module Configuring and Testing the SCXI-1141/1142/1143 Module Use MAX to configure and test the SCXI-1141/1142/1143 module. If you need help during the configuration process, open the MAX Help file by selecting from the menu Help»Help Topics»NI-DAQ. Follow these steps to configure the SCXI system: Double-click the Measurement &...

  • Page 23: Auto-Detecting Modules

    If the SCXI module is not connected to an NI device, select None. Select the appropriate scanning mode for the SCXI-1141/1142/1143 module by using the Operating Mode control. If parallel mode is selected, the checkbox labeled This device will control the chassis automatically becomes deselected.

  • Page 24: Manually Adding Modules

    If the SCXI module is not connected to an NI device, select None. Select the appropriate scanning mode for the SCXI-1141/1142/1143 module by using the Operating Mode control. If parallel mode is selected, the checkbox labeled This device will control the chassis automatically becomes deselected.

  • Page 25: Configuring The Scxi-1141/1142/1143 Module

    When you have completed configuration, click Finish. If you need to manually add more SCXI-1141/1142/1143 modules in the chassis, repeat steps 3 through 5 to configure each module. The SCXI chassis and SCXI module(s) should now be configured properly.

  • Page 26: Self-Test Verification

    Chapter 2 Installing and Configuring the SCXI-1141/1142/1143 Module Click the Channel tab. Select the appropriate gain and filter settings for each channel on the SCXI-1141/1142/1143 module. Click the Accessory tab. Select the terminal block you are using for this module.
  • Page 27 If the module is installed in the correct slot, power off the chassis, remove the module as specified in Removing the SCXI-1141/1142/1143 Module from an SCXI Chassis section, and verify that no connector pins are bent on the rear signal connector.

  • Page 28: Removing The Scxi-1141/1142/1143 Module

    Chapter 2 Installing and Configuring the SCXI-1141/1142/1143 Module Removing the SCXI-1141/1142/1143 Module This section describes how to remove the SCXI-1141/1142/1143 module from an SCXI chassis and from MAX. Removing the SCXI-1141/1142/1143 Module from an SCXI Chassis Only a qualified person who has read and understands all the safety information in this manual should remove an SCXI module.

  • Page 29: Removing The Scxi-1141/1142/1143 Module From Max

    Chapter 2 Installing and Configuring the SCXI-1141/1142/1143 Module ® 1 Cable 3 SCXI-1141/1142/1143 Module 5 SCXI Chassis Power Switch 2 SCXI Module Thumbscrews 4 Terminal Block 6 SCXI Chassis Figure 2-3. Removing the SCXI-1141/1142/1143 Module Removing the SCXI-1141/1142/1143 Module from MAX...

  • Page 30: Connecting The Signals

    Connections that exceed any of the maximum ratings of input or output signals Caution on the SCXI-1141/1142/1143 module can damage the SCXI-1141/1142/1143 module, the SCXIbus, any connected DAQ device, and the computer with which the DAQ device is used. NI is not liable for any damage resulting from such signal connections.
  • Page 31 Chapter 3 Connecting the Signals Table 3-1. SCXI-1141/1142/1143 Module Front Connector (Continued) Pin Number Column A Column B Column C IN4+ IN4– IN5+ IN5– AGND AGND IN6+ IN6– IN7+ IN7– RSVD RSVD RSVD RSVD RSVD EXTCLK DGND OUTCLK NC means not connected.

  • Page 32: Front Connector Signal Descriptions

    SCXI-1141/1142/1143 module instrumentation amplifiers is a function of the gain of the amplifiers, G, and is equal to 5 V/G. The common-mode input range of the SCXI-1141/1142/1143 module, however, is not a function of gain—the differential input amplifier rejects common-mode signals as long as the signal at both inputs is within ±5 V of the module...

  • Page 33: Figure 3-1. Ground-Referenced Signal Connection

    Exceeding the differential or common-mode input voltage limits distorts input signals. Exceeding the maximum common-mode input voltage rating can damage the SCXI-1141/1142/1143 module, the SCXIbus, and the DAQ device. NI is not liable for any damage resulting from such signal connections.

  • Page 34: Figure 3-2. Floating Signal Connection

    DC offset voltage proportional to the product of the input bias current and the resistor value used. The inputs of the SCXI-1141/1142/1143 module have a typical bias current of about ±200 pA. This bias current is highly dependent on the operating temperature of the module.

  • Page 35: Figure 3-3. Ground-Referenced Ac-Coupled Signal Connection

    IN– SCXI-1141/1142/1143 Figure 3-3. Ground-Referenced AC-Coupled Signal Connection µF Ω µF IN– Ω SCXI-1141/1142/1143 AGND Figure 3-4. Ground-Offset AC-Coupled Signal Connection 1 µF 1 MΩ IN– 100 kΩ SCXI-1141/1142/1143 AGND Figure 3-5. Floating AC-Coupled Signal Connection SCXI-1141/1142/1143 User Manual ni.com...

  • Page 36: Digital Input And Output

    Digital Input and Output You can use the EXTCLK input pin on the front connector of the SCXI-1141/1142/1143 module to control filter cutoff frequency for special purposes. The clock should be a TTL-logic-level or CMOS-logic-level square wave, with a frequency of less than 2.5 MHz that is 100 times the desired cutoff frequency.

  • Page 37: Rear Signal Connector

    Chapter 3 Connecting the Signals Rear Signal Connector If you use the SCXI-1141/1142/1143 module with a National Instruments DAQ Note device and SCXI cable assembly, you do not need to read the remainder of this chapter. If you also use the SCXI-1180 feedthrough panel, the SCXI-1343 rear screw-terminal adapter, or the SCXI-1351 one-slot cable extender with the SCXI-1141/1142/1143 module, you should read this section.

  • Page 38: Rear Signal Connection Descriptions

    6, 8, 10, 12, AGND Analog ground—these pins connect to the module analog 14, 16, 18 ground. They are used as the reference points for AOUT1 through AOUT7. © National Instruments Corporation SCXI-1141/1142/1143 User Manual...

  • Page 39: Analog Output Signal Connections

    The SCXI-1141/1142/1143 module analog outputs are not overvoltage protected, Caution although they are short-circuit protected. Applying external voltage to these outputs can result in damage to the SCXI-1141/1142/1143 module. NI is not liable for any damage resulting from such signal connections. Digital I/O Signal Connections Pins 24 through 27, 29, 33, 36, 37, and 43 constitute the digital I/O lines of the rear signal connector.

  • Page 40: Table 3-2. Scxibus To Scxi-1141/1142/1143 Module Rear Signal Connector To Daq Device Pin Equivalencies

    The digital output signal is pin 26. Pin 26 is SERDATOUT and is equivalent to the SCXIbus MISO serial data output line. The digital I/O signals of the SCXI-1141/1142/1143 module correspond to the digital I/O lines of an E Series MIO DAQ device. Table 3-2 lists the equivalencies.
  • Page 41 The digital timing signals are pins 36 and 43: • Pin 36 is SCANCLK, the signal used as a clock for the SCXI-1141/1142/1143 module multiplexer counter. The DAQ device pulses this signal at the end of each conversion if the module is in multiplexed mode.

  • Page 42: Theory Of Operation

    The usage and theory of operation of each of these components are explained in the remainder of this chapter. Power-Up State When the SCXI-1141/1142/1143 module is powered up or reset through software or the SCXI chassis reset button, the following states are defined: •...
  • Page 43 Chapter 4 Theory of Operation The cutoff frequency of the filters and the output clock frequency are not defined at power-up. The block diagram in Figure 4-1 illustrates the key functional components of the SCXI-1141/1142/1143 module. SCXI-1141/1142/1143 User Manual ni.com...
  • Page 44 Chapter 4 Theory of Operation Rear Signal Connector Analog Bus • • • • • • • • • • Calibration Calibration Selection Selection • • • Input Input Protection Protection Front Signal Connector © National Instruments Corporation SCXI-1141/1142/1143 User Manual...

  • Page 45: Digital Control Circuitry

    EEPROM for storing gain-calibration constants. The Module ID register contains 20 (hex) for the SCXI-1141 module, 35 (hex) for the SCXI-1142 module, and 34 (hex) for the SCXI-1143 module. You can read this module ID over the SCXIbus to determine the type of module that is in a particular slot.

  • Page 46: Correcting Gain And Offset Errors

    Offset errors also drift with changes in temperature, so you should update the offset correction periodically. Measurements made during the warm-up period of the module (approximately 20 minutes) and chassis are most susceptible to drifting offset errors. © National Instruments Corporation SCXI-1141/1142/1143 User Manual...

  • Page 47: Lowpass Filters

    (the passband) of signals that the filter is intended to pass from the input to the output without attenuation. Because the SCXI-1141/1142/1143 modules use a lowpass filter, this discussion is limited to lowpass filters. The ideal lowpass filter does not attenuate any input signal frequency components in the passband, which is defined as all frequencies below the cutoff frequency.

  • Page 48: Performance Of The Scxi-1141/1142/1143 Module Filters

    1. As Figure 4-4 shows, the SCXI-1141/1142/1143 module provides 80 dB attenuation above 1.5 times the cutoff frequency for the SCXI-1141 module, six times for the SCXI-1142 module, and 3.2 times for the ©...

  • Page 49: Figure 4-4. Typical Magnitude Response Of The Scxi-1141/1142/1143 Module Filters

    1 x 10 0.01 Frequency (normalized) Figure 4-4. Typical Magnitude Response of the SCXI-1141/1142/1143 Module Filters Figure 4-5 compares the magnitude response of the SCXI-1141/1142/1143 modules within the passband. The passband magnitude response begins to drop off immediately for the SCXI-1142 module. The SCXI-1141 performs much better than the SCXI-1142 in the passband, but it still exhibits about 0.1 dB of ripple in magnitude in the passband.

  • Page 50: Phase Response

    Group delay is defined as the negative derivative of the phase shift with respect to the frequency. In the ideal filter, group delay is a constant. The group delay of the SCXI-1141/1142/1143 module filters is shown in Figure 4-8.

  • Page 51: Figure 4-6. Phase Response Characteristics Of The Scxi-1141/1142/1143 Module Filters

    Butterworth (1143) –600 –800 Frequency (normalized) Figure 4-6. Phase Response Characteristics of the SCXI-1141/1142/1143 Module Filters Figures 4-7 and 4-8 show the advantages of the SCXI-1142 Bessel filter. The Bessel filter is designed for constant group delay at the expense of passband gain and stopband rolloff.

  • Page 52: Figure 4-7. Phase Error Of The Scxi-1141/1142/1143 Module

    Theory of Operation Elliptic (1141) Bessel (1142) Butterworth (1143) –100 Frequency (normalized) Figure 4-7. Phase Error of the SCXI-1141/1142/1143 Module Elliptic (1141) Bessel (1142) Butterworth (1143) Frequency (normalized) Figure 4-8. Group Delay of the SCXI-1141/1142/1143 Module © National Instruments Corporation...

  • Page 53: Figure 4-9. Unit Step Response Of The Scxi-1141/1142/1143 Module

    Theory of Operation The most common effect of phase nonlinearity is ringing in response to a step input. As Figure 4-9 shows, the SCXI-1141 elliptic filter exhibits the most overshoot and ringing and the SCXI-1142 Bessel filter has no overshoot or ringing. The SCXI-1143 module Butterworth filter has a step response that is a compromise between the SCXI-1141 module and the SCXI-1142 module.

  • Page 54: Setting The Cutoff Frequency

    If you use the filter to prevent aliasing, you must set the cutoff frequency no higher than one-third of the frequency at which that channel is being sampled for the SCXI-1141 module, one-twelfth of the frequency for the SCXI-1142 module, or one-sixth of the frequency for the SCXI-1143 module.

  • Page 55: Using The Scxi-1141/1142/1143 Module As An Antialiasing Filter

    SCXI-1141/1142/1143 module removes these high-frequency signals before they reach a DAQ device and cause aliasing. Because the SCXI-1141 module stopband begins at 1.5 times the cutoff frequency, the Nyquist frequency should be at least 1.5 times the cutoff frequency. Thus, the rate at which the DAQ device samples a channel should be at least three times the filter cutoff frequency to acquire meaningful data.

  • Page 56: Using The External Clock Input

    6.4 times the cutoff frequency to acquire meaningful data. For example, if a DAQ device is scanning all eight channels of the SCXI-1141 at a rate of 120,000 channels/s, the sample rate for each of the eight channels is: 120,000...
  • Page 57 The SCXI-1141/1142/1143 module prevents these errors by using sets of prefilters and postfilters that do not sample the signal. A different set of prefilters and postfilters is used for each of 12 ranges of input frequencies.

  • Page 58: Dc-Correction Circuitry And Overload Recovery

    Using this mode, you can examine an input signal without the added effects of passband ripple and phase nonlinearities. At power-up and at reset, all the channels of the SCXI-1141/1142/1143 module default to the filter bypass mode. © National Instruments Corporation...

  • Page 59: Rear Connector Analog Outputs

    The connector signals AOUT<1..7> and AGND are the outputs of channels 1 through 7. You can configure the OUTPUT and OUTPUT REF signals as any channel (0 through 7) of the SCXI-1141/1142/1143 module or as the output of a channel passed along the SCXIbus from any other module in the chassis.

  • Page 60: Parallel Mode

    In this mode, you can use an SCXI-1180 feedthrough panel to make each of the outputs available at the front of the chassis. A DAQ device cabled to an SCXI-1141/1142/1143 module in parallel mode reads a separate output signal from the module on each of its analog inputs.

  • Page 61: Calibrating The Scxi-1141/1142/1143 Module

    Calibrating the SCXI-1141/1142/1143 Module The onboard calibration hardware that calibrates the SCXI-1141/1142/1143 module consists of an EEPROM to store the gain calibration constants, calibration circuitry on the amplifier inputs, and a potentiometer to adjust the AC gain of the filter.

  • Page 62: Appendix A Specifications

    Specifications This appendix lists the specifications for the SCXI-1141/1142/1143 module. These specifications are typical at 25 °C and 50% humidity unless otherwise stated. Amplifier Characteristics Number of channels ....... 8 differential Output signal range ........ ±5 V Channel gains (software-selectable) ..1, 2, 5, 10, 20, 50, 100 Input overvoltage protection Powered on ........
  • Page 63 (for example, 25 kHz, 20 kHz, 16.7 kHz, 14.3 kHz, or from external) Passband ripple (SCXI-1141 module only) ......0.2 dB, DC to f Phase matching (SCXI-1142 only) ........3° max error at f Stopband attenuation SCXI-1141module......80 dB at 1.5 × f SCXI-1142 module......80 dB at 6 ×...

  • Page 64: Table A-1. Settling Time With Respect To Cutoff Frequency

    1 kHz..........–70 dB 0–25 kHz ........–60 dB × Input noise..........30 nV Output noise ........... 230 µV Stability Gain temperature coefficient....20 ppm/°C Input offset drift ........10 µV/°C Output offset drift........0.1 mV/°C © National Instruments Corporation SCXI-1141/1142/1143 User Manual...
  • Page 65 Rear connector.........50-pin male ribbon-cable Front connector........96-pin DIN C male (screw-terminal adapters available) Maximum Working Voltage Maximum working voltage refers to the signal voltage plus the common-mode voltage. Channel-to-earth ........±5 V, Installation Category I Channel-to-channel.........±10 V, Installation Category I SCXI-1141/1142/1143 User Manual ni.com...
  • Page 66 Humidity ..........5 to 90% noncondensing Maximum altitude ........2000 m Pollution degree (indoor use only)..2 Safety The SCXI-1141/1142/1143 meets the requirements of the following standards for safety and electrical equipment for measurement, control, and laboratory use: • EN 61010-1:1993/A2:1995, IEC 61010-1:1990/A2:1995 •...
  • Page 67 Technical Support Resources Web Support National Instruments Web support is your first stop for help in solving installation, configuration, and application problems and questions. Online problem-solving and diagnostic resources include frequently asked questions, knowledge bases, product-specific troubleshooting wizards, manuals, drivers, software updates, and more. Web support is available through the Technical Support section of ni.com...
  • Page 68 Appendix B Technical Support Resources Worldwide Support National Instruments has offices located around the world to help address your support needs. You can access our branch office Web sites from the Worldwide Offices section of . Branch office Web sites provide ni.com...
  • Page 69 ≥ greater than or equal to < less than ≤ less than or equal to – negative of, or minus Ω ohms percent ± plus or minus positive of, or plus © National Instruments Corporation SCXI-1141/1142/1143 User Manual...
  • Page 70 CMOS complementary metal-oxide semiconductor CMRR common-mode rejection ratio common-mode noise noise that appears on both inputs of a differential amplifier cutoff frequency the frequency that defines the upper end of the passband of a lowpass filter SCXI-1141/1142/1143 User Manual ni.com...
  • Page 71 EEPROM electrically erasable programmable read-only memory EXTCLK external clock signal cutoff frequency external frequency gain gain error the difference between the actual and intended gain of a system hexadecimal (base 16) hertz © National Instruments Corporation SCXI-1141/1142/1143 User Manual...
  • Page 72 NRSE nonreferenced single-ended Nyquist frequency the frequency that a sampling system can accurately reproduce, which is half the sampling frequency SCXI-1141/1142/1143 User Manual ni.com...
  • Page 73 © National Instruments Corporation SCXI-1141/1142/1143 User Manual...
  • Page 74 (a LabVIEW program) volts, root mean square working voltage the highest voltage that should be applied to a product during normal use, normally well under the breakdown voltage for safety margin SCXI-1141/1142/1143 User Manual ni.com...
  • Page 75 Index antialiasing filter, using SCXI-1141/1142/1143 as, 4-14 AC-coupled signal connections AOUT signal (table), 3-9 floating (figure), 3-6 auto-detecting modules, 2-11 ground-offset (figure), 3-6 ground-referenced (figure), 3-6 AGND signal front connector (table), 3-3 bypassing filters, 4-17 rear connector (table), 3-9 aliasing...
  • Page 76 (table), 3-1 emulation of SCXIbus signal descriptions (table), 3-3 communication signals, 3-10 functional overview of SCXI-1141. See theory SCXIbus to SCXI-1141/1142/1143 of operation pin equivalencies (table), 3-11 digital I/O specifications, A-4 gain and offset correction, 4-5...
  • Page 77 4-17 Alliance Program, B-1 filter theory, 4-6 customer education, B-1 overload recovery, 4-17 Developer Zone, B-1 performance of SCXI-1141 filters system integration services, B-1 magnitude response, 4-7 technical support, B-1 phase response, 4-9 Web support, B-1 response to step input (figure), 4-7...
  • Page 78 DAQ device connections SCXI-1141/1142/1143 from SCXI for, 2-8 chassis, 2-16 passband, lowpass filters, 4-6 removing modules from MAX, 2-17 performance of SCXI-1141/1142/1143 filters requirements for getting started, 1-2 magnitude response, 4-7 ripple, real filters, 4-7 phase response, 4-9 phase response, SCXI-1141/1142/1143 filters...
  • Page 79 4-13 digital I/O connections, 3-11 transfer function characteristics specifications (figure), 4-6 amplifier characteristics, A-1 major components of SCXI-1141, 4-1 digital I/O, A-4 power-up state, 4-1 electromagnetic compatibility, A-5 training, customer, B-1 environmental characteristics, A-5 transfer functions of lowpass filters...
  • Page 80 Index unpacking the SCXI-1141/1142/1143, 2-1 Web support from National Instruments, B-1 worldwide technical support, B-2 SCXI-1141/1142/1143 User Manual ni.com...

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