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SCXI-1600 User Manual - National Instruments

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1. 3 4 Nn Launch LabWindows CVI Open a new or existing project From the menu bar select Tools Create Edit DAQmx Tasks Choose Create New Task In MAX or Create New Task In Project to load the DAQ Assistant Configure the NI DAQm x task The DAQ Assistant creates the code for the task based on the parameters you define in MAX and the device defaults To change a property of the channel programmatically use the DAQmxSetChanAt tribute function 3 Note Refer to the NI LabWindows CVI Help for more information about creating NI DAQmx tasks in LabWindows CVI and NI DAQm x property information SCX I 1600 User Manual 4 8 ni com Chapter 4 Using the SCXI 1600 Measurement Studio Visual Basic NET and C You cannot use the create a task capabilities of Visual Basic NET and C with the SCXI 1600 Refer to the user documentation for the hardware and software used in your system to create NET or C tasks for other modules in the system Programmable NI DAQmx Properties All of the different ADEs that configure the SCXI 1600 access an underlying set of NI DAQmx properties For a complete list of NI DAQmx properties refer to your ADE help file Other Application Documentation and Material Refer to the ADE documentation and the DAQ analog input examples for your application software for more detailed information about programming the SCXI modules for scanning in multiplexed mode Calibrating the SCXI 1600 System The
2. eee cece eeeeeseteeeeeeseeeseeneees 4 6 National Instruments Corporation vii SCXI 1600 User Manual About the SCXI 1600 This chapter introduces the SCXI 1600 USB digitizer module The SCXI 1600 module is a high performance plug and play USB device used for direct connection between USB compatible computers and SCXI systems The SCXI 1600 module is a USB data acquisition DAQ device that features a 16 bit ADC The SCXI 1600 receives analog signals from other SCXI modules and amplifies digitizes and sends data through a USB port The SCXI 1600 can also control digital input digital output and analog output SCXI modules The SCXI 1600 has no DIP switches jumpers or potentiometers It is easily configured and calibrated using software The SCXI 1600 connects to other SCXI modules to acquire up to 352 analog signals from thermocouples RTDs strain gauges voltage sources and current sources It is USB compatible which supports hot or powered insertion into the USB port You need not power down the computer to connect to an SCXI system UN Caution SCXI modules are not hot swappable Refer to the Installing the SCXI 1600 section for proper installation instructions The SCXI 1600 module is based on E Series DAQ devices and uses the National Instruments DAQ STC system timing controller for time related functions The DAQ STC makes possible such applications as equivalent time sampling and seamlessly changing the sampling rate
3. pulse after AI SAMP CLK generates a conversion Separate the AI SAMP CLK pulses by at least one scan period A counter on the SCXI 1600 module internally generates the AI SAMP CLK signal unless you select an external source This counter is started by the AI START TRIG signal and is stopped either by software or by the sample counter Scans generated by either an internal or external AI SAMP CLK signal are inhibited unless they occur within a data acquisition sequence Either the hardware AI GATE signal or software command register gate can gate scans occurring within a data acquisition sequence National Instruments Corporation B 7 SCXI 1600 User Manual Appendix B Timing Signal Information Al CONV CLK Signal SCX I 1600 User Manual Any PFI pin can externally input the AI CONV CLK signal Refer to Figure B 8 for the relationship of AI CONV CLK to the data acquisition sequence As an input the AI CONV CLK signal is configured in the edge detection mode You can select any PFI pin as the source for AI CONV CLK and configure the polarity selection for either rising or falling edge The selected edge of the AI CONV CLK signal initiates an A D conversion Figure B 8 shows the input timing requirements for the AI CONV CLK signal Al SAMP CLK tw 25 to 50 ns a Start of Scan Start Pulse i Al CONV CLK ot _ il Al SAMP CLK _ tof 10 ns minimum 1 te i b Scan in Progre
4. 3 2 shows that the AI CONV CLK signal is generated from sources including the external signals PFI lt 0 7 gt and the internal signal sample interval counter TC SCX I 1600 User Manual 3 4 ni com Chapter 3 Theory of Operation Programmable Function Inputs The two PFIs connect to the signal routing multiplexer for each timing signal and software can select one of the PFIs as the external source for a given timing signal You can use the two PFIs as an input by any of the timing signals and multiple timing signals can use the same PFI simultaneously This flexible routing scheme reduces the need to change physical connections to the I O connector for different applications You also can enable each of the PFI pins individually to output a specific internal timing signal For example if you need the AI SAMP CLK signal as an output on the I O connector software can power on the output driver for the PFI 7 AI SAMP CLK pin Multiplexed Operation The SCXI 1600 operates in multiplexed mode digitizing the conditioned signals from other SCXI modules and communicating with the host through the USB port In multiplexed mode all input channels of an SCXI module are multiplexed into a single analog input channel of the DAQ device Multiplexed mode operation is ideal for high channel count systems The power of SCXI multiplexed mode scanning is its ability to route many input channels to a single channel of the SCXI 1600 The mul
5. Channel Strings in NI DAQMX 0 0 0 ccc ecceeeeeeeeeseeee cee eneteeteees 4 8 Developing an Application Using Text Based ADE5S eee eeeeeeeeeeeeeees 4 8 Tab Wiindows CV Lorier seein Gib Baad aee e aaia 4 8 Measurement Studio Visual Basic NET and C eee 4 9 Programmable NI DAQmx Properties ssseseeesseeeseseeesrrererrsreerseese 4 9 Other Application Documentation and Material sssssssesessssesesesesststsesenereseseseserens 4 9 Calibrating the SCXI 1600 System sseessesesssrssesresrsresrsrrsrrstesrsrestsresrestsrenresrnrestrersrest 4 9 Internal Calibration Procedure 0 0 eee eececeeseceseeseceeesseeeseesesseceaeeseeeaseneeeaes 4 9 Internal Calibration Using MAX ooo ee eeeeeceeceeeeeesseeaecnseeaecneeeaeeneeaes 4 10 Internal Calibration Using LabVIEW 0 0 0 eeeeseeeeceeeseeeseeeeeesesseeesetsees 4 10 External Calibratiomcsc c ii tectcasiedess sods otesetadeea ss aE A A ANAR RAE 4 11 Calibrating the System sist erroa aroraa feaden is tadesschusdaved desde E a RR des Eao E opa SEER eaa 4 11 Appendix A Specifications Appendix B Timing Signal Information Appendix C Removing the SCXI 1600 Appendix D Common Questions Glossary Index SCXI 1600 User Manual vi ni com Contents Figures Figure 2 1 Cable between the SCXI 1600 and the Computer USB Port Of USB RUD 3 sess aeei ce Seong ne tense Ean aea ected wages DaN VEENAS 2 1 Figure 2 2 SCXI 1600 Module Front Panel Connectors 0 eee eeeeee
6. Chapter 4 Using the SCXI 1600 Configuring Channel Properties All ADEs used to configure the SCXI 1600 access an underlying set of NI DAQmx properties For a complete list of NI DAQmx properties refer to your ADE help file For LabVIEW specifically refer to Help VI Function amp How To Help and search for your specific module to find the DAQmx channel properties available for you module To learn how to use the channel properties refer to the Using a DAQmx Channel Property Node in LabVIEW section 3 Note You cannot adjust some properties while a task is running For these properties you must stop the task make the adjustment and restart the application Acquiring Analyzing and Presenting After configuring the task and channels you can start the acquisition read measurements analyze the data returned and display it according to the needs of your application Typical methods of analysis include digital filtering averaging data performing harmonic analysis applying a custom scale or adjusting measurements mathematically NI provides powerful analysis toolsets for each NI ADE to help you perform advanced analysis on the data without requiring you to have a programming background After you acquire the data and perform any required analysis it is useful to display the data in a graphical form or log it to a file NI ADEs provide easy to use tools for graphical display such as charts graphs slide controls and gauge indicator
7. DIFF A channel configured in DIFF mode connects the positive analog input line to the positive input of the PGIA and the negative analog input line to the negative input of the PGIA Specifically all the analog input channels coming from the input SCXI modules are multiplexed to analog channel 0 on the SCXI backplane The signals are then accepted into the SCXI 1600 Input Polarity Input Range and Gain The SCXI 1600 module has a software programmable gain to obtain the highest level of precision It matches the input signal range to a range the ADC can accommodate using the gains available Specifically the SCXI 1600 has a bipolar input range of 10 V 5 V and gains of 0 5 1 10 and 100 With the proper gain which is set by the driver software the full resolution of the ADC is used to measure the input signal The gain on the signals are set using the gain on the SCXI analog input module multiplied with the gain on the SCXI 1600 Table 3 1 shows the overall input range and precision of the SCXI 1600 according to the input range configuration and gain used Table 3 1 Actual Range and Measurement Precision Range Configuration Gain Actual Input Range Precision 5 to 5 V 0 5 10 to 10 V 305 2 uV 1 0 5 to 5 V 152 6 uV 10 0 500 to 500 mV 15 26 uV 100 00 50 to 50 mV 1 53 uV ADC 16 bit count 1 The value of 1 LSB of the 16 bit ADC that is the voltage increment corresponding to a change of one count in th
8. INSTRUMENTS THE USER OR APPLICATION DESIGNER IS ULTIMATELY RESPONSIBLE FOR VERIFYING AND VALIDATING THE SUITABILITY OF NATIONAL INSTRUMENTS PRODUCTS WHENEVER NATIONAL INSTRUMENTS PRODUCTS ARE INCORPORATED IN A SYSTEM OR APPLICATION INCLUDING WITHOUT LIMITATION THE APPROPRIATE DESIGN PROCESS AND SAFETY LEVEL OF SUCH SYSTEM OR APPLICATION Conventions lt gt gt g bold italic monospace The following conventions are used in this manual Angle brackets contain values associated with a bit or signal name The symbol leads you through nested menu items and dialog box options to a final action The sequence File Page Setup Options directs you to pull down the File menu select the Page Setup item and select Options from the last dialog box This icon denotes a note which alerts you to important information This icon denotes a caution which advises you of precautions to take to avoid injury data loss or a system crash When this icon is marked on the product refer to the Read Me First Safety and Radio Frequency Interference document shipped with the product for precautions to take When symbol is marked on a product it denotes a warning advising you to take precautions to avoid electrical shock When symbol is marked on a product it denotes a component that may be hot Touching this component may result in bodily injury Bold text denotes items that you must select or click in the software such as me
9. SCXI 1600 ships with a calibration certificate and is calibrated at the factory to the specifications described in Appendix A Specifications Calibration constants are stored inside the calibration EEPROM and provide software correction values your application development software uses to correct the measurements for offset errors in the module To assure the highest level of accuracy you must periodically calibrate the SCXI 1600 Calibrating the module ensures its accuracy In the EEPROM there is a user modifiable calibration area in addition to the permanent factory calibration area The user modifiable calibration area allows you to load the CalDACs with values either from the original factory calibration or from a calibration that you subsequently performed Internal Calibration Procedure The SCXI 1600 incorporates internal calibration paths that allow routing channel inputs to ground and an onboard reference voltage NI software disconnects the channel inputs from the front signal connector and reconnects the inputs to ground and an onboard reference when performing an internal calibration You need not change any input connections for an internal calibration National Instruments Corporation 4 9 SCXI 1600 User Manual Chapter 4 Using the SCXI 1600 This internal calibration process which generally takes less than two minutes is the preferred method of assuring accuracy in your application Initiate an internal calibra
10. codes 16 bits Offset error Pregain error after calibration 1 0 uV max Pregain error before calibration 28 8 mV max Postgain error after calibration 157 uV max Postgain error before calibration t40 mV max Gain error relative to calibration reference After calibration gain 1 74 ppm of reading max Before calibration cceeeeseeeeee 18 900 ppm reading max Gain 1 with gain error adjusted to 0 at gain Low 200 ppm of reading max A 2 ni com Appendix A Specifications Amplifier Characteristics Input impedance normal ee 100 GQ parallel with 100 pF External calibration BNC input impedance Normal powered on sses 100 GQ parallel with 100 pF Powered Off ccccccsscseseseteteteeee 820 Q Overload iscsiscucsscsssasseesdaietitieediieg 820 Q Input bias current eecececeseeseeeteeeees 200 pA Common mode rejection ratio CMRR DC to 60 Hz Gain Bipolar 0 5 1 85 dB 10 100 96 dB Dynamic Characteristics Bandwidth Signal Bandwidth Small 3 dB 413 kHz Large 1 THD 490 kHz Settling time for full scale step Gain LOO ict eae aes 4 LSB 5 us typ Gain 10 1 O 5 vc ccccececeseseeeee 2 LSB 5 us max The resistance value is taken from the AD829 op amp specification sheet and is a value much smaller than the mux or other op amps The 100 pF is taken from the mux specification sheet and is
11. input voltage ratings which are listed in Table 2 2 T O Signal Summary can damage the SCXI 1600 module and the computer NI is not liable for any damages resulting from such signal connections Timing connections are grouped into the following categories e PFI connections e DAQ timing connections e General purpose timing signal connections PFIs are bidirectional pins As outputs they are not programmable and reflect the state of many DAQ and general purpose timing signals As inputs the PFI signals are programmable and can control any DAQ and general purpose timing signals All external control over the timing of the SCXI 1600 module is routed through these two PFIs that are labeled PFI 0 and PFI 7 All digital timing connections are referenced to digital ground This reference is shown in Figure B 1 which shows an example of how to connect an external AI START TRIG source and an external AI CONV CLK source to two of the SCXI 1600 module PFI pins National Instruments Corporation B 1 SCXI 1600 User Manual Appendix B Timing Signal Information PFI O Al START TRIG PFI 7 Al CONV CLK Al START TRIG Source Al CONV CLK Source i D GND a 1 O Connector SCXI 1600 Module Figure B 1 Timing I O Connections Programmable Function Input Connections SCX I 1600 User Manual There are a total of 13 internal
12. much larger than the op amps 2 This value is the input protection resistor in front of the analog input mux 3 The input bias current is taken from the AD829 op amp specification sheet This value is much larger than the other op amps Since the AD829 is used as a single ended op amp the input bias current is the same as the input offset current Therefore offset current is not listed National Instruments Corporation A 3 SCXI 1600 User Manual Appendix A Specifications System noise LSB s including quantization Gain LSByms 0 5 1 0 1 0 10 0 1 3 100 6 6 Stability Recommended warm up time 15 min Offset temperature coefficient PLE SAIN eax sstsesssessiscisckosseessecermeatanee 20 uV C Postal ar E EEE 175 uV C Gain temperature coefficient 20 ppm C Triggers Al triggers Tin ptesin 228 SiS hes Bea ee beset AI START TRIG AI REF TRIG AI SAMP CLK AI CONV CLK AI GATE SI SOURCE OQUUPULE rssmi AI Start Trigger AI Sample Clock External SOULCES ccccccsssccccesesseeeeeees PFI lt 0 7 gt Compatibility 2 ereeeeereeee 5 V TTL RESPONSE ivise cece cevizsexecavecesestessncasedesses cosets Rising or falling edge SCXI 1600 User Manual A 4 ni com Appendix A Specifications Pulseswidthts 206 vince a sevieee 10 ns min in edge detect mode Direction Level Min Max Input Low voltage 0 0 V 0 8 V High voltage 2 0 V 5 0 V Output Low
13. running them through special metal conduits For more information refer to the Field Wiring and Noise Consideration for Analog Signals application note available at ni com National Instruments Corporation 2 5 SCXI 1600 User Manual Theory of Operation This chapter discusses the theory of operational measurement concepts Figure 3 1 shows the block diagram for the SCXI 1600 module EXT CAL Analog Analog ADC USB Interface DAQ APE DAQ STC PFI Trigger PFI Lines Figure 3 1 SCXI 1600 Module Block Diagram A D Converter Configuration Memory SCXIBus Digital I O Timing Analog Input When setting up an SCXI system using the SCXI 1600 module follow the analog input setup instructions of the input SCXI modules The input mode on the SCXI 1600 does not affect the input used on the analog input National Instruments Corporation 3 1 SCXI 1600 User Manual Chapter 3 Theory of Operation Input Mode modules The detailed analog input descriptions of the digitizer provide information regarding the functionality of the SCXI 1600 The analog input portion of the board acquires analog signals from the SCXI chassis backplane and prepares the signal for digital conversion The type of input the input range and the software configurable gain of the SCXI 1600 are described in detail in the following sections The SCXI 1600 module input mode is differential
14. timing signals that you can externally control from the PFI pins The source for each of these signals is software selectable from any of the PFIs when you want external control This flexible routing scheme reduces the need to change the physical wiring to the device I O connector for different applications requiring alternative wiring You can individually enable the PFI pins to output a specific internal timing signal For example if you need the AI CONV CLK signal as an output on the I O connector software powers on the output driver for the PFI 7 AI CONV CLK pin Do not drive a PFI signal externally when it is configured as an output When used as an input you can individually configure each PFI for edge or level detection and for polarity selection You can use the polarity selection for any of the 13 timing signals but the edge or level detection depends B 2 ni com Appendix B Timing Signal Information upon the particular timing signal being controlled The detection requirements for each timing signal are listed within the section that discusses that individual signal In edge detection mode the minimum pulse width required is 10 ns This applies for both rising edge and falling edge polarity settings There is no maximum pulse width requirement in edge detect mode In level detection mode there are no minimum or maximum pulse width requirements imposed by the PFIs themselves but limits can be imposed by the particular tim
15. voltage Igy 5 mA 0 4 V High voltage Isu 3 5 mA 4 35 V Calibration Recommended warm up time Interval External calibration reference Onboard calibration reference j EE E P REEE ET Temperature coefficient Long term stability eee Power Requirement 22 V supply 22 V supply Physical Dimensions D x Hx W I O connector National Instruments Corporation A 5 5 000 V 3 5 mV over full operating temperature actual value stored in EEPROM 5 ppm C max 15 ppm 1 000 h 115 mA max 135 mA max 18 3 cm x 17 3 cm x 3 1 cm 7 2 in X 6 8 in x 1 2 in 3 BNC connectors 1 USB front connector SCXI 1600 User Manual Appendix A Specifications Maximum Working Voltage Environmental Safety Maximum working voltage refers to the signal voltage plus the common mode voltage Channel to earth 0 00 eee eeeeeeeeee 11 V Installation Category I Channel to channel eee eee 11 V Installation Category I Operating temperature 0 0 ee 0 to 50 C Storage temperature ee eee 20 to 70 C H midity ssepe 10 to 90 RH noncondensing Maximum altitude 2 000 m Pollution Degree indoor use only 2 The SCXI 1600 is designed to meet the requirements of the following standards of safety for electrical equipment for measurement control and laboratory use e IEC 61010 1 EN 61010 1 e UL61010 1 e CAN CSA C22 2 No 6
16. 1010 1 3 Note For UL and other safety certifications refer to the product label or visit ni com certification search by model number or product line and click the appropriate link in the Certification column SCXI 1600 User Manual A 6 ni com Appendix A Specifications Electromagnetic Compatibility EMISSIONS cccccccceececeseeseseessensesteeeeees EN 55011 Class A at 10 m FCC Part 15A above 1 GHz IMMUN c aieencene EN 61326 1997 A2 2001 Table 1 EMC EML 0 cecccccccccccccccececeeeeeeseeeseeeeas CE C Tick and FCC Part 15 Class A Compliant 3 Note For EMC compliance operate this device with shielded cabling CE Compliance The SCXI 1600 meets the essential requirements of applicable European Directives as amended for CE marking as follows Low Voltage Directive safety 73 23 EEC Electromagnetic Compatibility Directive EMC rretsi ninis 89 336 EEC ay Note Refer to the Declaration of Conformity DoC for this product for any additional regulatory compliance information To obtain the DoC for this product visit ni com certification search by model number or product line and click the appropriate link in the Certification column National Instruments Corporation A 7 SCXI 1600 User Manual Timing Signal Information This appendix contains information about the timing signals discussed in Chapter 3 Theory of Operation Connecting Timing Signals Caution Exceeding the maximum
17. 4 2 differential mode 3 2 displaying data 4 5 4 6 documentation conventions used in the manual iv National Instruments documentation 1 3 dynamic characteristics specifications A 3 E edge detection mode B 3 electromagnetic compatibility specifications A 7 end to end calibration See system calibration SCX I 1600 User Manual l 2 environmental specifications A 6 error specifications A 2 example finder 4 3 examples LabVIEW 4 3 LabWindows CVI 4 3 EXT CAL signal 2 3 external calibration 4 11 F FAQ See common questions FIFO memory 3 6 finding examples See example finder first in first out memory 3 6 flexible scanning 3 5 frequently asked questions See common questions front panel connectors 2 2 G gain 3 2 getting started items needed documentation 1 2 hardware 1 2 software 1 2 green LED 1 5 2 2 H hot swapping caution 1 1 input gain 3 2 mode See differential mode polarity 3 2 range 3 2 ni com selecting ranges 3 3 input characteristics specifications A 1 installation software 1 4 internal calibration 4 9 See also calibration using LabVIEW 4 10 using MAX 4 10 L LabVIEW developing your application 4 5 Example Finder 4 3 programming a task table 4 6 using a DAQmx Channel Property Node in LabVIEW 4 7 using a while loop for continuous sampling 4 6 LabWindows CVI 4 8 developing your application 4 8 Example Finder 4 3 LEDs green R
18. AI START TRIG pin to a logic high when the output is in a high impedance state D 2 ni com Glossary Symbol Prefix Value p pico 10 1 n nano 10 u micro 10 6 m milli 10 3 k kilo 103 M mega 106 G giga 10 T tera 10 Numbers Symbols percent plus or minus 2 degrees per positive of or plus negative of or minus lt less than gt greater than lt less than or equal to gt greater than or equal to Q ohms 5V 5 VDC source signal National Instruments Corporation G 1 SCXI 1600 User Manual Glossary A A AID AC ADC ADC resolution AI CONV CLK AI GATE AI SAMP CLK amplification ASIC bipolar BNC buffer bus SCXI 1600 User Manual amperes analog to digital alternating current analog to digital converter an electronic device often an integrated circuit that converts an analog voltage to a digital number the resolution of the ADC which is measured in bits A 16 bit ADC has a higher resolution and thus a higher degree of accuracy than a 12 bit ADC convert signal analog input gate signal start scan signal a type of signal conditioning that improves accuracy in the resulting digitized signal and reduces noise application specific integrated circuit bit one binary digit either 0 or 1 byte eight related bits of data an 8 bit binary number Also used to denote the amount of memory required to store one b
19. EADY 1 5 2 2 pattern descriptions 1 4 patterns for SCXI 1600 USB states table 1 5 power 2 2 yellow ACTIVE 1 5 2 2 level detection mode B 3 linearity specifications A 2 MAX Test Panels 2 4 maximum scan rate calculating 3 3 maximum working voltage A 6 Measurement Studio 4 9 developing your application 4 9 examples 4 4 measurements calibrating SCXI 1600 4 9 National Instruments Corporation l 3 Index multiplexed mode multiplexers 3 5 note regarding SCXI 1600 operation 2 4 theory of operation 3 5 multiplexed operation See multiplexed mode N NI DAQ required version 1 4 specifying channel strings in NI DAQmx 4 8 NI DAQmx properties configuring channel properties 4 5 programmable NI DAQm x properties 4 9 noise 2 5 P PFI See programmable function input physical specifications A 5 plug and play 1 1 polarity 3 2 selection B 2 posttrigger acquisition sequences 2 3 posttriggered data acquisition B 3 typical acquisition figure B 3 power LEDs 2 2 power requirement specifications A 5 precision range and measurement table 3 2 pretrigger acquisition sequences 2 3 pretriggered data acquisition B 3 typical acquisition figure B 4 program flowchart discussion of typical program flowchart 4 3 typical flowchart 4 1 figure 4 2 SCXI 1600 User Manual Index programmable function input 3 5 PFI 0 2 3 PFI 7 2 3 timing signal connections B 2 programming See de
20. I DAQ before you install the SCXI module The SCXI Quick Start Guide This document describes how to set up an SCXI chassis install SCXI modules and terminal blocks and configure the SCXI system in Measurement amp Automation Explorer MAX Getting Started with SCXI Read this manual first It gives an overview of the SCXI system and contains the most commonly needed information for the modules chassis and software SCXI chassis manual This manual contains installation instructions and maintenance information about the chassis The SCXI hardware user manuals Read these manuals next for detailed information about signal connections and module configuration They also explain in greater detail how the module works and contain application hints Accessory installation guides or manuals If you are using accessory products read the terminal block and cable assembly installation guides They explain how to physically connect the relevant pieces of the system Consult these guides when you are making the connections Software documentation You may have both application software and NI DAQ software documentation NI application software includes LabVIEW LabWindows CVI and Measurement Studio After you set up the hardware system use either your application software documentation or the NI DAQ documentation to help you write your application If you have a large complex system it is worthwhile to look through the software
21. LK As an output the AI SAMP CLK signal reflects the actual start pulse that initiates a scan This is true even if the starts are externally triggered by another PFI You have two output options The first is an active high pulse with a pulse width of 50 to 100 ns which indicates the start of the scan The second action is an active high pulse that terminates at the start of the last conversion in the scan which indicates a scan in progress AI SAMP CLK deasserts to off after the last conversion in the scan is initiated This output is set to high impedance at startup Figure B 6 and Figure B 7 show the input and output timing requirements for the AI SAMP CLK signal rf gt Rising Edge Polarity Falling Edge Polarity ty 10 ns minimum Figure B 6 Al SAMP CLK Input Signal Timing B 6 ni com Appendix B Timing Signal Information lt al Al SAMP CLK _ ty 50 to 100 ns a Start of Scan Start Pulse a a a D Al CONV CLK AISAMP CLK i lt gt totp 10 ns minimum tae b Scan in Progress Two Conversions per Scan Figure B 7 Al SAMP CLK Output Signal Timing The AI CONV CLK pulses are masked off until the device generates the AI SAMP CLK signal If you are using internally generated conversions the first AI CONV CLK appears when the onboard sample interval counter reaches zero If you select an external AI CONV CLK the first external
22. SCXT SCXI 1600 User Manual USB 16 Bit Digitizer Module Qr NATIONAL September 2004 Edition p INSTRUMENTS Part Number 373364C 01 Worldwide Technical Support and Product Information ni com National Instruments Corporate Headquarters 11500 North Mopac Expressway Austin Texas 78759 3504 USA Tel 512 683 0100 Worldwide Offices Australia 1800 300 800 Austria 43 0 662 45 79 90 0 Belgium 32 0 2 757 00 20 Brazil 55 11 3262 3599 Canada Calgary 403 274 9391 Canada Ottawa 613 233 5949 Canada Qu bec 450 510 3055 Canada Toronto 905 785 0085 Canada Vancouver 604 685 7530 China 86 21 6555 7838 Czech Republic 420 224 235 774 Denmark 45 45 76 26 00 Finland 385 0 9 725 725 11 France 33 0 1 48 14 24 24 Germany 49 0 89 741 31 30 India 91 80 51190000 Israel 972 0 3 6393737 Italy 39 02 413091 Japan 81 3 5472 2970 Korea 82 02 3451 3400 Malaysia 603 9131 0918 Mexico 01 800 010 0793 Netherlands 31 0 348 433 466 New Zealand 0800 553 322 Norway 47 0 66 90 76 60 Poland 48 22 3390150 Portugal 351 210 311 210 Russia 7 095 783 68 51 Singapore 65 6226 5886 Slovenia 386 3 425 4200 South Africa 27 0 11 805 8197 Spain 34 91 640 0085 Sweden 46 0 8 587 895 00 Switzerland 41 56 200 51 51 Taiwan 886 2 2528 7227 Thailand 662 992 7519 United Kingdom 44 0 1635 523545 For further support information refer to the Signal Conditioning Technical Support Information document To comment on National Instruments documentation refer
23. SE SIGNIFICANT INJURY TO A HUMAN 2 IN ANY APPLICATION INCLUDING THE ABOVE RELIABILITY OF OPERATION OF THE SOFTWARE PRODUCTS CAN BE IMPAIRED BY ADVERSE FACTORS INCLUDING BUT NOT LIMITED TO FLUCTUATIONS IN ELECTRICAL POWER SUPPLY COMPUTER HARDWARE MALFUNCTIONS COMPUTER OPERATING SYSTEM SOFTWARE FITNESS FITNESS OF COMPILERS AND DEVELOPMENT SOFTWARE USED TO DEVELOP AN APPLICATION INSTALLATION ERRORS SOFTWARE AND HARDWARE COMPATIBILITY PROBLEMS MALFUNCTIONS OR FAILURES OF ELECTRONIC MONITORING OR CONTROL DEVICES TRANSIENT FAILURES OF ELECTRONIC SYSTEMS HARDWARE AND OR SOFTWARE UNANTICIPATED USES OR MISUSES OR ERRORS ON THE PART OF THE USER OR APPLICATIONS DESIGNER ADVERSE FACTORS SUCH AS THESE ARE HEREAFTER COLLECTIVELY TERMED SYSTEM FAILURES ANY APPLICATION WHERE A SYSTEM FAILURE WOULD CREATE A RISK OF HARM TO PROPERTY OR PERSONS INCLUDING THE RISK OF BODILY INJURY AND DEATH SHOULD NOT BE RELIANT SOLELY UPON ONE FORM OF ELECTRONIC SYSTEM DUE TO THE RISK OF SYSTEM FAILURE TO AVOID DAMAGE INJURY OR DEATH THE USER OR APPLICATION DESIGNER MUST TAKE REASONABLY PRUDENT STEPS TO PROTECT AGAINST SYSTEM FAILURES INCLUDING BUT NOT LIMITED TO BACK UP OR SHUT DOWN MECHANISMS BECAUSE EACH END USER SYSTEM IS CUSTOMIZED AND DIFFERS FROM NATIONAL INSTRUMENTS TESTING PLATFORMS AND BECAUSE A USER OR APPLICATION DESIGNER MAY USE NATIONAL INSTRUMENTS PRODUCTS IN COMBINATION WITH OTHER PRODUCTS IN A MANNER NOT EVALUATED OR CONTEMPLATED BY NATIONAL
24. The DAQ STC consists of three timing groups that control analog input Detailed specifications of the SCXI 1600 module are in Appendix A Specifications National Instruments Corporation 1 1 SCXI 1600 User Manual Chapter 1 About the SCXI 1600 What You Need to Get Started To set up and use the SCXI 1600 module you need the following m 3 m SCXI 1600 User Manual Hardware SCXI 1600 module supplied with a USB cable Analog input analog output or digital I O SCXI module SCXI chassis Personal computer or a PXI controller with a USB port Cabling cable adapter and sensors as required for your application Note The SCXI 1600 is not compatible with the PXI SCXI combination chassis Software NI DAQ 7 3 or later One of the following e LabVIEW LabWindows CVI Documentation SCXI 1600 User Manual DAQ Quick Start Guide SCXI Quick Start Guide Read Me First Safety and Radio Frequency Interference Documentation for your software 1 2 ni com Chapter 1 About the SCXI 1600 National Instruments Documentation The SCXI 1600 User Manual is one piece of the documentation set for DAQ systems You could have any of several types of documents depending on the hardware and software in the system Use the documents you have as follows The DAQ Quick Start Guide This document describes how to install NI DAQ devices and NI DAQ You must install N
25. are not saved to a task in MAX Adjust Timing Settings The DAQmx Timing VI Sample Clock by default is optional if you optional created and configured your task using the DAQ Assistant Any timing settings modified with this VI are not saved in the task in the DAQ Assistant They are only available for the present session Configure Channels optional DAQmx Channel Property Node refer to the Using a DAQmx Channel Property Node in LabVIEW section for more information This step is optional if you created and fully configured the channels in your task using the DAQ Assistant Any channel modifications made with a channel property node are not saved in the task in the DAQ Assistant They are only available for the present session Start Measurement DAQnmx Start Task VI Read Measurement DAQm x Read VI Analyze Data Some examples of data analysis include filtering scaling harmonic analysis or level checking Some data analysis tools are located on the Functions Signal Analysis subpalette and on the Functions All Functions Analyze subpalette Display Data You can use graphical tools such as charts gauges and graphs to display your data Some display tools are located on the Controls Numeric Indicators subpalette and Controls All Controls Graph subpalette Continue Sampling For continuous sampling use a While Loop If you are using hardware timing you also need to set the DAQmx Timing VI sam
26. calibration constants 4 9 EEPROM 4 9 external calibration 4 11 internal calibration overview 4 9 procedure for 4 9 using LabVIEW 4 10 using MAX 4 10 specifications A 5 system calibration 4 11 C based environment programming See developing your application channel sequencing 3 5 channel strings specifying in NI DAQmx 4 8 charge injection 3 3 combination chassis compatibility note 1 2 common questions D 1 completing the application 4 5 connecting signals 2 3 connecting the SCXI 1600 to USB port or hub figure 2 1 connectors BNC 2 1 signal descriptions 2 3 table 2 3 USB 2 1 conventions used in the manual iv D DAQ Assistant 4 3 DAQmx 4 7 SCXI 1600 User Manual Index DAQmx Channel Property Node 4 6 using a DAQmx Channel Property Node in LabVIEW 4 7 DAQmx Clear Task VI 4 7 DAQmx Create Task VI 4 6 DAQm x Read VI 4 6 DAQmx Self Calibrate VI 4 10 DAQmx Start Task VI 4 6 DAQmx Stop Task VI 4 7 DAQmx Timing VI 4 6 DAQ STC 1 1 3 4 data analysis 4 5 4 6 developing your application acquiring analyzing and presenting 4 5 adjusting timing and triggering 4 4 completing the application 4 5 configuring channel properties 4 5 creating a task using the DAQ Assistant or Programmatically 4 3 examples LabVIEW 4 3 LabWindows CVI 4 3 in LabVIEW 4 5 specifying active channels 4 7 in LabWindows CVI 4 8 in Measurement Studio 4 9 in NI DAQmx 4 1 typical program flowchart figure
27. can counter indicates the minimum number of scans before AI REF TRIG is recognized After the scan counter decrements to zero it is loaded with the number of posttrigger scans to acquire while the acquisition continues The device ignores the AI REF TRIG signal if it is asserted prior to the scan counter decrementing to zero After the selected edge of AI REF TRIG is received the device acquires a fixed number of scans and the acquisition stops This mode acquires data both before and after receiving AI REF TRIG Figure B 5 shows the input timing requirements for the AI REF TRIG signal Rising Edge Polarity Falling Edge Polarity ty 10 ns minimum Figure B 5 Al REF TRIG Input Signal Timing National Instruments Corporation B 5 SCXI 1600 User Manual Appendix B Timing Signal Information Al SAMP CLK Signal SCX I 1600 User Manual Any PFI pin can externally input the AI SAMP CLK signal which is available as an output on the PFI 7 AI SAMP CLK pin Refer to Figure B 6 and Figure B 7 for the relationship of AI SAMP CLK to the data acquisition sequence As an input the AI SAMP CLK signal is configured in the edge detection mode You can select any PFI pin as the source for AI SAMP CLK and configure the polarity selection for either rising or falling edge The selected edge of the AI SAMP CLK signal initiates a scan The sample interval counter is started if you select internally triggered AI CONV C
28. detection mode the first active edge disables the AI SAMP CLK signal and the second active edge enables AI SAMP CLK The AI GATE signal can neither stop a scan in progress nor continue a previously gated off scan in other words once a scan has started AI GATE does not gate off conversions until the beginning of the next scan and conversely if conversions are gated off AI GATE does not gate them back on until the beginning of the next scan SI SOURCE Signal Any PFI pin can externally input the SI SOURCE signal The onboard scan interval counter uses the SI SOURCE signal as a clock to time the generation of the AI SAMP CLK signal You must configure the PFI pin you select as the source for the SI SOURCE signal in the level detection mode You can configure the polarity selection for the PFI pin for either active high or active low The maximum allowed frequency is 20 MHz with a minimum pulse width of 23 ns high or low There is no minimum frequency limitation National Instruments Corporation B 9 SCXI 1600 User Manual Appendix B Timing Signal Information Either the 20 MHz or 100 kHz internal timebase generates the SI SOURCE signal unless you select an external source Figure B 9 shows the timing requirements for the SI SOURCE signal tp 50 ns minimum ty 23 ns minimum Figure B 9 SI SOURCE Signal Timing SCX I 1600 User Manual B 10 ni com Removing the SCXI 1600 This appendix explains
29. documentation before you configure the hardware Refer to Start Programs National Instruments NI DAQ NI DAQmx Help for software information You can download NI documents from ni com manuals National Instruments Corporation 1 3 SCXI 1600 User Manual Chapter 1 About the SCXI 1600 Installing the Application Software NI DAQmx and the DAQ Device Refer to the DAQ Quick Start Guide packaged with the NI DAQ software to install your application software and NI DAQm x driver software NI DAQmx 7 3 or later is required to configure and program the SCXI 1600 module If you do not have NI DAQmx 7 3 or later you can either contact an NI sales representative to request it on a CD or download the latest NI DAQmx version from ni com downloads Installing the SCXI 1600 3 Note Refer to the Read Me First Radio Frequency Interference document before removing equipment covers or connecting or disconnecting any signal wires Refer to the SCXT Quick Start Guide to unpack install and configure the SCXI 1600 in an SCXI chassis After installing the SCXI 1600 power on the SCXI chassis The computer should detect the SCXI chassis and all its modules If the SCXI 1600 does not initialize properly you must restart the SCXI chassis with the power on switch LED Pattern Descriptions SCX I 1600 User Manual There are four LEDs on the front of the SCXI 1600 that confirm the signal conditioning system is functioning properly a
30. e Note Refer to Appendix A Specifications for absolute maximum ratings SCX I 1600 User Manual 3 2 ni com Chapter 3 Theory of Operation Considerations for Selecting Input Ranges of an SCXI System The range that you select depends on the expected range of the incoming signal A large input range can accommodate a large signal variation but reduces the voltage resolution Choosing a smaller input range improves the voltage resolution but can result in the input signal going out of range For best results match the input range as closely as possible to the expected range of the input signal For example if you are certain the input signal is between 50 mV specify this range If the signal is less than 50 mV or greater than 50 mV inaccurate readings occur Calculating the Maximum Scan Rate The SCXI 1600 module can scan multiple channels at a high rate To calculate the maximum permitted scan rate when using one or more SCXI modules in multiplexed mode use the following maximum permitted scan rate nena lee ee ee 5 us x number of channels scanned In this equation the term number of channels scanned is the number of all the channels scanned in a chassis Scanning Considerations The settling time for the SCXI 1600 module is independent of the selected gain With the SCXI 1600 the gain is constant and the source impedance is low Refer to Appendix A Specifications for a complete listing of settling times f
31. ea fet bbaaidle ities Masta deo Gadi eh eee es 3 2 Input Polarity Input Range and Gain eee eeeereceeceseeeeetseseeetaeenees 3 2 Considerations for Selecting Input Ranges of an SCXI System 3 3 Calculating the Maximum Scan Rate ee cece eseeeeeeseceeeeseeseeeseesensetaeenaes 3 3 Scanning Considerations s sinisini oi e i e aa ia 3 3 Timi g Signal ROUN iiics niniin ET R cduebactesees 3 4 Programmable Function Inputs ssssssssssssessesesssssssersesesessssssesisenenensesesenesenses 3 5 Multiplexed Operation an n i aa aaas siss 3 5 Chapter 4 Using the SCXI 1600 Developing Your Application in NI DAQMX eee eeeceeseesneceseeeteeceaeeeeeeceaeeeseeeeaeensees 4 1 Typical Program Flowchart issena a ea a E RE 4 1 General Discussion of Typical Flow Chart sseeseeesseesseeseersrrsresrsresesresresese 4 3 Creating a Task Using the DAQ Assistant or Programmatically 4 3 Adjusting Timing and Triggering 0 0 ceeeeeeeeneeeeeeeeceteeseneeeaeeeee 4 4 Configuring Channel Properties cee eeeeseeseceeeseeeseeeeneeeseeeees 4 5 Acquiring Analyzing and Presenting 0 0 0 0 cee eceseeseeeeereeneeeees 4 5 Completing the Application 0 0 elie eseeseeseceecesecseeeseeneeeseeeaes 4 5 National Instruments Corporation v SCXI 1600 User Manual Contents Developing an Application Using LabVIEW 0 cece eeeeseeeeesecreeeeeeeeees 4 5 Using a DAQmx Channel Property Node in LabVIEW 4 7 Specifying
32. easure in LSB of the worst case deviation of code widths from their ideal value of 1 LSB software that controls a specific hardware device such as a DAQ device electromechanical compliance the condition or state of an analog or digital signal a voltage pulse from an external source that causes a DAQ operation to begin first in first out a type of signal conditioning that allows you to remove unwanted frequency components from the signal you are trying to measure the factor by which a signal is amplified sometimes expressed in dB a measure of deviation of the gain of an amplifier from the ideal gain a counter input pin that controls when counting occurs in your application signal sources that are connected to ground hertz cycles per second of a periodic signal input output identification SCXI 1600 User Manual Glossary in INL input bias current input impedance input offset current instrumentation amplifier K kS L linearity LSB SCXI 1600 User Manual inch or inches integral nonlinearity a measure in LSB of the worst case deviation from the ideal A D or D A transfer characteristic of the analog I O circuitry the current that flows into the inputs of a circuit the measured resistance and capacitance between the input terminals of a circuit the difference in the input bias currents of the two inputs of an instrumentation amplifier a very accurate differential amplifier with a hi
33. eeeeeeeeeeee 2 2 Figure 3 1 SCXI 1600 Module Block Diagram eee cece eeeeseeeeeeseeneetaes 3 1 Figure 3 2 AICONV CLK Signal Routing o oo eee eeeeeeceeeeneteeeeseeeeeeaees 3 4 Figure 4 1 Typical Program Flowchatt eceecseseeseeseceseceseeesaeeeaeeeseecsaeeeseeesaes 4 2 Figure B 1 Timing I O Connections 0000 eseeeeceeeseeeseeseeeseeaeeneeeaeseeeeseenees B 2 Figure B 2 Typical Posttriggered ACquiSition eee eee eeseeseceeceeeeeeeeseeeeeeseenees B 3 Figure B 3 Typical Pretriggered Acquisition eee eecceseeeeseceeeteeeeeeseeeeeeaees B 4 Figure B 4 AI START TRIG Input Signal Timing 0000 eee eeeereeees B 4 Figure B 5 AI REF TRIG Input Signal Timing eee eee ceetseeeeeeees B 5 Figure B 6 AISAMP CLK Input Signal Timing 0 eeeeeseeeeeereeeees B 6 Figure B 7 AI SAMP CLK Output Signal Timing eee eects eeeeeneeees B 7 Figure B 8 AICONV CLK Input Signal Timing 00 eeeeeetseeeeeaees B 8 Figure B 9 SI SOURCE Signal Timing eee ceceseceeeeeceeeseeeneeeeseeeaees B 10 Figure C 1 Removing the SCXI 1600 00 cece eseesseeneeesecseensetaeeneeeneenaes C 2 Tables Table 1 1 LED Patterns for SCXI 1600 USB States 2 0 eee eeeeeeeeeeneeeeeeeeeeeee 1 5 Table 2 1 I O Connector Signal Descriptions eee cece eeeeseeeeeeseeeeeeseeseeeaeens 2 3 Table 2 2 VO Signal Summary iana e EEE N 2 4 Table 3 1 Actual Range and Measurement Precision seeeesererereeeereeerrrsereesre 3 2 Table 4 1 Programming a Task in LabVIEW
34. expressed in scans per second Signal Conditioning eXtensions for Instrumentation a device that converts a physical phenomenon into an electrical signal the amount of time required for a voltage to reach its final value within specified accuracy limits SI counter clock signal the manipulation of signals to prepare them for digitizing a programmed event that triggers an event such as data acquisition a parameter of signal sources that reflects current driving ability of voltage sources lower is better and the voltage driving ability of current sources higher is better system timing controller an ADC that sequentially compares a series of binary weighted values with an analog input to produce an output digital word in n steps where n is the bit resolution of the ADC devices that do not require dip switches or jumpers to configure resources on the devices See also Plug and Play devices a measure of the amount of noise seen by an analog circuit or an ADC when the analog inputs are grounded terminal count total harmonic distortion See sensor a type of signal conditioning that uses external voltages and currents to excite the circuitry of a signal conditioning system into measuring physical phenomena SCXI 1600 User Manual Glossary trigger TTL U USB VDC VI W wire working voltage SCX I 1600 User Manual any event that causes or starts some form of data capture transistor transistor logic un
35. g Signals This section describes the SCXI 1600 I O signals 1 0 Connector Signal Descriptions Table 2 1 1 0 Connector Signal Descriptions Signal Name Reference Direction Description PFI 0 AI START TRIG D GND Input PFI 0 Trigger 1 As an input this is either one of the PFIs or the source for the hardware digital trigger PFI signals are explained in Appendix B Timing Signal Information Output As an output this is the AI START TRIG signal In posttrigger data acquisition sequences a low to high transition indicates the initiation of the acquisition sequence In pretrigger applications a low to high transition indicates the initiation of the pretrigger conversions PFI 7 SAMP CLK D GND Input PFI 7 Start of scan As an input this is one of the PFIs Output As an output this is the SAMP CLK signal This pin pulses once at the start of each analog input scan in the interval scan A low to high transition indicates the start of the scan EXT CAL AI GND Input External calibration This input is used for external calibration of the SCXI 1600 The DC source must be more accurate than 10 ppm National Instruments Corporation 2 3 SCXI 1600 User Manual Chapter 2 AN Connecting Signals Table 2 2 shows the I O signal summary for the SCXI 1600 module Caution Exceeding the maximum input voltage ratings which are listed in Table 2 2 can damage the SCXI 1600 module and t
36. gh input impedance kilo the standard metric prefix for 1 000 or 103 used with units of measure such as volts hertz and meters 1 000 samples the adherence of device response to the equation R KS where R response S stimulus and K a constant least significant bit meters 1 Mega the standard metric prefix for 1 million or 10 when used with units of measure such as volts and hertz 2 mega the prefix for 1 048 576 or 270 when used with B to quantify data or computer memory G 6 ni com multiplexed mode mux NI DAQ nodes noise P peak to peak PFI PGIA Plug and Play devices port potentiometer ppm National Instruments Corporation G 7 Glossary an SCXI operating mode in which analog input channels are multiplexed into one module output so that the cabled DAQ device has access to the multiplexed output of the module as well as the outputs of all other multiplexed modules in the chassis multiplexer a switching device with multiple inputs that sequentially connects each of its inputs to its single output typically at high speeds in order to measure several signals with a single analog to digital converter the driver software needed in order to use National Instruments DAQ devices and SCXI components execution elements of a block diagram consisting of functions structures and subVIs an undesirable electrical signal Noise comes from external sources such as the AC powe
37. gh the menus and select the property to define 7 Change the property to either read the property or to write a new value National Instruments Corporation Right click the property go to Change To and select Write Read or Default Value 4 7 SCXI 1600 User Manual Chapter 4 Using the SCXI 1600 After you have added the property to the property node right click the terminal to change the attributes of the property add a control constant or indicator To add another property to the property node right click an existing property and left click Add Element To change the new property left click it and select the property you wish to define nye Note Refer to the LabVIEW Help for information about property nodes and specific NI DAQmx properties Specifying Channel Strings in NI DAQmx You cannot specify channel strings on the SCXI 1600 Refer to the user documentation for the hardware and software used in your system to specify channel strings for other modules in the system Developing an Application Using Text Based ADEs You can use text based ADEs such as LabWindows CVI Measurement Studio Visual Basic NET and C to create code for using the SCXI 1600 LabWindows CVI LabWindows CVI works with the DAQ Assistant in MAX to generate code for a task You can then use the appropriate function call to modify the task To create a configurable channel or task in LabWindows CVI complete the following steps 1 2
38. gure Channels Yes y Adjust Timing Settings Configure Channels Da y Start Measurement y Analyze Data No Process Data Display Data Graphical Display Tools No Yes Read Measurement Continue Sampling Stop Measurement Clear Task Figure 4 1 Typical Program Flowchart SCXI 1600 User Manual 4 2 ni com Chapter 4 Using the SCXI 1600 General Discussion of Typical Flow Chart The following sections briefly discuss some considerations for a few of the steps in Figure 4 1 These sections are meant to give an overview of some of the options and features available when programming with NI DAQmx Creating a Task Using the DAQ Assistant or Programmatically When creating an application you first must decide whether to create the appropriate task using the DAQ Assistant or programmatically in the ADE Developing your application using the DAQ Assistant allows you to configure most settings such as measurement type selection of channels signal input limits task timing and task triggering You can access the DAQ Assistant through MAX or your NI ADE Choosing to use the DAQ Assistant can simplify the development of your application NI recommends creating tasks using the DAQ Assistant for ease of use when using a sensor that requires complex scaling or when many properties differ between channels in the same task If you are using a
39. he computer NI is not liable for any damages resulting from such signal connections Table 2 2 1 0 Signal Summary Protection Volts Source Sink Rise Signal Name Drive On Off mA at V mA at V Time ns Bias PFI 0 DIO 24 V 3 5 at 5 at 0 4 1 5 50 KQ pu AI START TRIG Vcc 0 4 PFI 7 DIO 24 V 3 5 at 5 at 0 4 1 5 50 KQ pu AI SAMP CLK Vcc 0 4 EXT CAL Al 24 V AI analog input DIO digital input output pu pullup and 100 kQ Note The tolerance on the 50 KQ pullup and pulldown resistors is very large Actual values can range between 17 kQ The SCXI 1600 controls the SCXI system and digitizes analog signals from the other modules in the system and has no configurable settings For information about configuring other modules in the system refer to the module user manuals and the SCXI Quick Start Guide Notes The SCXI 1600 operates in multiplexed mode only The SCXI 1600 has no Test Panels in MAX and is grayed out You can perform Test Chassis to verify the presence of the SCXI 1600 SCXI 1600 User Manual 2 4 ni com Chapter 2 Connecting Signals Field Wiring Considerations Environmental noise can seriously affect the accuracy of measurements made with the SCXI system if you do not take proper precautions when running signal wires between signal sources and the module The following recommendations apply mainly to analog input signal routing b
40. hem PFIs are programmable function inputs These lines serve as connections to virtually all internal timing signals If you are using the NI DAQ language interface or Measurement Studio use the Select_Signal function to route internal signals to the I O connector route external signals to internal timing sources or connect internal timing signals National Instruments Corporation D 1 SCXI 1600 User Manual Appendix D Common Questions If you are using NI DAQ with LabVIEW and you want to connect external signal sources to the PFI lines refer to the Multi Synch Shared Ext Sample Clk vi as an example of making these connections Caution If you enable a PFI line for output do not connect any external signal source to it If you do you can damage the device the computer and the connected equipment SCX I 1600 User Manual What are the power on states of the PFIs At system power on and reset the PFI lines are set to high impedance by the hardware This means that the device circuitry is not actively driving the output either high or low However these lines can have pull up or pull down resistors connected to them as shown in Table 2 1 O Connector Signal Descriptions These resistors weakly pull the output to either a logic high or logic low state For example PFI 0 AI START TRIG is in the high impedance state after power on and Table 2 1 shows that there is a 50 KQ pull up resistor This pull up resistor sets the PFI 0
41. how to remove an SCXI 1600 module from an SCXI chassis and MAX Removing the SCXI 1600 from an SCXI Chassis To remove the SCXI 1600 from an SCXI chassis complete the following steps 1 Disconnect the USB cable running from the SCXI 1600 to the computer or USB hub 2 Power off the SCXI chassis Do not remove the SCXI 1600 from a chassis that is powered on 3 Rotate the thumbscrews that secure the SCXI 1600 to the chassis counterclockwise until they are loose but do not completely remove the thumbscrews 4 Remove the SCXI 1600 by pulling steadily on both thumbscrews until the module slides out completely National Instruments Corporation C 1 SCXI 1600 User Manual Appendix C Removing the SCXI 1600 1 Thumbscrews 2 SCXI 1600 3 Power Switch 4 SCXI Chassis Figure C 1 Removing the SCXI 1600 Removing the SCXI 1600 from MAX To remove the SCXI 1600 module from MAX disconnect the USB cable or power off the SCXI chassis If the SCXI 1600 is still detected press the lt F5 gt key aye Note When the SCXI 1600 is no longer detected in MAX neither is the SCXI chassis in which it is located along with the other modules in the chassis SCX I 1600 User Manual The SCXI 1600 SCXI chassis and other SCXI modules are not automatically removed from MAX when the USB cable is disconnected They still appear in the list but have a red X indicating they are disabled If the USB cable is reconnected and the chassis is
42. i com zone Programmatically adjusting properties for a task created in the DAQ Assistant overrides the original or default settings only for that session The changes are not saved to the task configuration The next time you load the task the task uses the settings originally configured in the DAQ Assistant Adjusting Timing and Triggering There are several timing properties that you can configure through the DAQ Assistant or programmatically using function calls or property nodes If you create a task in the DAQ Assistant you can still modify the timing properties of the task programmatically in your application When programmatically adjusting timing settings you can set the task to acquire continuously acquire a buffer of samples or acquire one point at a time For continuous acquisition you must use a While Loop around the acquisition components even if you configured the task for continuous acquisition using MAX or the DAQ Assistant For continuous and buffered acquisitions you can set the acquisition rate and the number of samples to read in the DAQ Assistant or programmatically in your application By default the clock settings are automatically set by an internal clock based on the requested sample rate You also can select advanced features such as clock settings that specify an external clock source internal routing of the clock source or select the active edge of the clock signal SCX I 1600 User Manual 4 4 ni com
43. ing signal being controlled Data Acquisition Timing Connections The data acquisition timing signals are the following e AI START TRIG e AIREF TRIG e AISAMP CLK e AICONV CLK e AI GATE e SI SOURCE Posttriggered data acquisition allows you to view only data that is acquired after a trigger event is received Figure B 2 shows a typical posttriggered data acquisition sequence Pretriggered data acquisition allows you to view data that is acquired before the trigger of interest in addition to data acquired after the trigger Figure B 3 shows a typical pretriggered data acquisition sequence Al START TRIG Al SAMP CLK Al CONV CLK Waa Scan Counter 4 3 2 1 0 Figure B 2 Typical Posttriggered Acquisition National Instruments Corporation B 3 SCXI 1600 User Manual Appendix B Timing Signal Information Al START TRIG 3 maeme m NL nsec S SL tt woowee UI A Ar Scan Counter 3 2 i1 0 12 i2 2 11 i0 Figure B 3 Typical Pretriggered Acquisition Al START TRIG Signal SCX I 1600 User Manual Any PFI pin can externally input the AI START TRIG signal Refer to Figure B 4 for the relationship of AI START TRIG to the data acquisition sequence As an input the AISTART TRIG signal is configured in the edge detection mode You can select any PFI pin as the s
44. is chapter describes how to develop your application and provides basic information about calibration Developing Your Application in NI DAQmx This section describes how to configure and use NI DAQmx to control the SCXI 1600 in LabVIEW LabWindows CVI and Measurement Studio These ADEs provide greater flexibility and access to more settings than MAX but you can use ADEs in conjunction with MAX to quickly create a customized application Refer to the SCXI Quick Start Guide for general SCXI configuration information 3 Note Ifyou are not using an NI ADE using an NI ADE prior to version 7 0 or using an unlicensed copy of an NI ADE additional dialog boxes from the NI License Manager appear allowing you to create a task or global channel in unlicensed mode These messages continue to appear until you install version 7 0 or later of an NI ADE Typical Program Flowchart Figure 4 1 shows a typical program flowchart for creating a task to configure the SCXI 1600 channels take a measurement analyze the data present the data stop the measurement and clear the task National Instruments Corporation 4 1 SCXI 1600 User Manual Chapter 4 Using the SCXI 1600 Yes Create Task Using No DAQ Assistant y Create a Task Programmatically Create Custom Channel Hardware Timing Triggering Create Task in DAQ Assistant or MAX Create Another Channel No Further Confi
45. iversal serial bus volts volts direct current virtual instrument 1 a combination of hardware and or software elements typically used with a computer that has the functionality of a classic stand alone instrument 2 a LabVIEW software module VI which consists of a front panel user interface and a block diagram program data path between nodes the highest voltage with respect to ground that should be applied to an input terminal during normal use normally well under the breakdown voltage for safety margin Includes both the signal and common mode voltages G 10 ni com Index A accuracy information A 2 acquisition sequences posttrigger 2 3 pretrigger 2 3 active channels 4 7 ACTIVE LED 1 5 2 2 AI CONV CLK signal B 8 AI CONV CLK signal routing figure 3 4 AI CONV CLK signal timing figure B 8 AI GATE signal B 9 AI REF TRIG signal B 5 AI REF TRIG signal timing figure B 5 AI SAMP CLK input signal timing figure B 6 AI SAMP CLK output signal timing figure B 7 AI SAMP CLK signal B 6 AI START TRIG signal 2 3 B 4 AI START TRIG signal timing figure B 4 amplifier characteristics specifications A 3 analog input specifications A 1 theory of operation 3 1 analog input mode See differential mode analyzing data 4 5 4 6 ANSI C See Measurement Studio block diagram SCXI 1600 figure 3 1 BNC connectors 2 1 buffer FIFO See FIFO memory National Instruments Corporation C
46. l Support Information document to contact NI for support National Instruments Corporation 1 5 SCXI 1600 User Manual Connecting Signals This chapter describes how to make input and output signal connections to the SCXI 1600 module using the device I O connectors The following connector types are located on the front panel e Three BNC connectors These connectors are used to access PFI 0 AI START TRIG and PFI 7 AI SAMP CLK and to perform external calibration For calibration information refer to Chapter 4 Using the SCXI 1600 e USB connector This connector is used to communicate and transfer data between the computer and SCXI 1600 module Figure 2 1 illustrates the connection requirements Figure 2 1 Cable between the SCXI 1600 and the Computer USB Port or USB Hub Figure 2 2 shows the SCXI 1600 connectors National Instruments Corporation 2 1 SCXI 1600 User Manual Chapter 2 Connecting Signals SCX I 1600 User Manual Y7 NATIONAL p INSTRUMENTS NI SCXI 1600 6 vV POWER ACTIVE OC PFIO AI START TRIG Q PFI7 Al SAMP CLK STRAIN RELIEF D 200 kS s 16 BIT DIGITIZER FOR USB A 1 Power Monitor LEDs 4 USB Connector 2 USB ACTIVE and READY LEDs 5 Strain Relief 3 BNC Connectors Figure 2 2 SCXI 1600 Module Front Panel Connectors 2 2 ni com Chapter 2 Connecting Signals Connectin
47. n ADE other than an NI ADE or if you want to explicitly create and configure a task for a certain type of acquisition you can programmatically create the task from your ADE using functions or VIs If you create a task using the DAQ Assistant you can still further configure the individual properties of the task programmatically with functions or property nodes in your ADE NI recommends creating a task programmatically if you need explicit control of programmatically adjustable properties of the DAQ system Each API includes a collection of programming examples to help you start developing an application You can modify example code and save it in an application You can use examples to develop a new application or add example code to an existing application To locate LabVIEW and LabWindows CVI examples open the National Instruments Example Finder e In LabVIEW select Help Find Examples e In LabWindows CVI select Help NI Example Finder National Instruments Corporation 4 3 SCXI 1600 User Manual Chapter 4 Using the SCXI 1600 Measurement Studio Visual Basic and ANSI C examples are in the following directories e NI DAQmx examples for Measurement Studio supported languages are in the following directories MeasurementStudio VCNET Examples NIDaq MeasurementStudio DotNET Examples NIDaq e NI DAQmx examples for ANSI C are in the NI DAQ Examples DAQmx ANSI C Dev directory For additional examples refer to n
48. nal B 5 AI REF TRIG signal timing figure B 5 AI SAMP CLK input signal timing figure B 6 AI SAMP CLK output signal timing figure B 7 AI SAMP CLK signal B 6 AI START TRIG 2 3 AI START TRIG signal B 4 AI START TRIG signal timing figure B 4 connecting 2 3 EXT CAL 2 3 T O connector description 2 3 T O summary table 2 4 routing signal wires 2 5 ni com SAMP CLK 2 3 SI SOURCE signal B 9 SI SOURCE signal timing figure B 10 timing signal routing 3 4 software application development environments supported 1 4 installation 1 4 specifications accuracy information A 2 amplifier characteristics A 3 analog input A 1 calibration A 5 dynamic characteristics A 3 electromagnetic compatibility A 7 environmental A 6 error A 2 input characteristics A 1 linearity A 2 maximum working voltage A 6 physical A 5 power requirement A 5 regulatory compliance A 7 resolution A 1 safety A 6 sampling rate A 1 stability A 4 transfer characteristics A 2 triggers A 4 stability specifications A 4 system calibration 4 11 T taking measurements See measurements task creation 4 3 Test Panels MAX 2 4 theory of operation analog input 3 1 timing adjusting timing and triggering 4 4 connecting timing signals B 1 National Instruments Corporation l 5 Index data acquisition connections B 3 data acquisition signals B 3 T O connections figure B 2 selecting polarity B 2 signal informati
49. nu items and dialog box options Bold text also denotes parameter names Italic text denotes variables emphasis a cross reference hardware labels or an introduction to a key concept This font also denotes text that is a placeholder for a word or value that you must supply Text in this font denotes text or characters that you should enter from the keyboard sections of code programming examples and syntax examples This font is also used for the proper names of disk drives paths directories programs subprograms subroutines device names functions operations variables filenames and extensions Contents Chapter 1 About the SCXI 1600 What You Need to Get Started piaren usni e e oiae desea aer 1 2 National Instruments Documentation cecceeeeeseessececeesneceseeececeaeeeeeeceaeeeseeesaeeeaees 1 3 Installing the Application Software NI DAQmx and the DAQ Device 1 4 Installing the SCXI 1 600 rriei i erra E RAE ne ea as 1 4 LED Pattern Descriptions oasen acess cd oleate aves tutea casd a a cess ela a a E E a e 1 4 Chapter 2 Connecting Signals Connecting Sigast 2 3 T O Connector Signal Descriptions sseeessesessessetsresrsrrsrrersrrsrrsesrrsrsrrsresrstee 2 3 Field Wiring Considerations 00 0 0 ccc eceeseeeeseceecesesseeeseseeeeseeseesaeeseseeecasensesseseeeeaeenaes 2 5 Chapter 3 Theory of Operation Analog Inputs rnana Basie c hati esi Ate a Mia tadlagdeetestiseas 3 1 Input Mode 25 nd a
50. on B 1 timing signals B 3 information B 1 routing 3 4 transfer characteristics specifications A 2 trigger specifications A 4 triggering adjusting timing and triggering 4 4 specifications A 4 U USB connector 2 1 V VIs DAQmx Clear Task VI 4 7 DAQmx Create Task VI 4 6 DAQm x Read VI 4 6 DAQmx Self Calibrate 4 10 DAQmx Start Task VI 4 6 DAQmx Stop Task VI 4 7 DAQmx Timing VI 4 6 Visual Basic See Measurement Studio voltage ratings caution 2 4 W While Loop 4 6 wiring considerations 2 5 Y yellow LED 1 5 2 2 SCXI 1600 User Manual
51. or the SCXI 1600 module The low source impedance of the SCXI 1600 module keeps the settling time low Settling times can increase when scanning high impedance signals due to a phenomenon called charge injection where the analog input multiplexer injects a small amount of charge into each signal source when that source is selected If the source impedance is not low enough the effect of the charge a voltage error does not decay by the time the ADC samples the signal National Instruments Corporation 3 3 SCXI 1600 User Manual Chapter 3 Theory of Operation Timing Signal Routing The DAQ STC provides a very flexible interface for connecting timing signals to other devices or external circuitry The SCXI 1600 module uses two programmable function input PFI pins on the I O connector for connecting to external circuitry These connections enable the SCXI 1600 to control and be controlled by other devices and circuits You can control a total of 13 timing signals internal to the DAQ STC by an external source You also can control these timing signals by signals generated internally to the DAQ STC These selections are fully software configurable The signal routing multiplexer for controlling the AI CONV CLK signal on the SCXI 1600 is shown in Figure 3 2 PFIO gt PFI7 gt Sample Interval Counter TC gt m gt Al CONV CLK a Figure 3 2 Al CONV CLK Signal Routing Figure
52. ource for AI START TRIG and configure the polarity selection for either rising or falling edge The selected edge of the AI START TRIG signal starts the data acquisition sequence for both posttriggered and pretriggered acquisitions Figure B 4 shows the input requirements for the AI START TRIG signal 1 1 1 w 1 lt gt Rising Edge Polarity Falling Edge Polarity ty 10 ns minimum Figure B 4 Al START TRIG Input Signal Timing B 4 ni com Appendix B Timing Signal Information The device also uses the AI START TRIG signal to initiate pretriggered data acquisition operations In most pretriggered applications the AI START TRIG signal is generated by a software trigger Refer to the AI REF TRIG signal description for a complete description of the use of AI START TRIG and AI REF TRIG in a pretriggered data acquisition operation Al REF TRIG Signal Any PFI pin can externally input the AI REF TRIG signal Refer to Figure B 5 for the relationship of AI REF TRIG to the data acquisition sequence As an input the AI REF TRIG signal is configured in the edge detection mode You can select any PFI pin as the source for AI REF TRIG and configure the polarity selection for either rising or falling edge The selected edge of the AI REF TRIG signal initiates the posttriggered phase of a pretriggered acquisition sequence In pretriggered mode the AI START TRIG signal initiates the data acquisition The s
53. ox select the device corresponding to the SCXI 1600 and run the VI Note The SCXI 1600 takes a few seconds to perform the calibration 4 10 ni com Chapter 4 Using the SCXI 1600 After the VI has completed running the SCXI 1600 has new calibration constants stored for all gain settings and the module is calibrated External Calibration You can download all available external calibration documents from ni com calibration by clicking Manual Calibration Procedures NI recommends you perform an external calibration once a year Calibrating the System After the SCXI 1600 is calibrated perform a system calibration using the SCXI 1600 with the SCX input module in the system to improve accuracy This is considered system or end to end calibration Follow the calibration procedures for the SCXI input module National Instruments Corporation 4 11 SCXI 1600 User Manual Specifications Analog Input This appendix lists the specifications of the SCXI 1600 module These specifications are typical at 25 C unless otherwise noted Input Characteristics Type oP AD Ge ievessrtinet ce ecencenicon Successive approximation RESOlUUHON s reni entada eenei 16 bits 1 in 65 536 Sampling rate 0 eee eeeete s 200 kS s Device Gain Range 0 5 10 V 1 5 V 10 500 mV 100 50 mV Input coupling sesseeseeesseseesrerrererrereeree DC FIFO buffer size seser 4 096 samples Data transfers s eseeseseeee
54. ple mode to Continuous Samples Right click the sample mode terminal of the DAQmx Timing VI and click Create Constant Click the box that appears and select Continuous Samples SCX I 1600 User Manual 4 6 ni com Chapter 4 Using the SCXI 1600 Table 4 1 Programming a Task in LabVIEW Continued Flowchart Step VI or Program Step Stop Measurement The DAQmx Stop Task VI clears the task and automatically stops the optional task Clear Task DAQmx Clear Task VI Using a DAQmx Channel Property Node in LabVIEW You can use property nodes in LabVIEW to manually configure the channels To create a LabVIEW property node complete the following steps Launch LabVIEW 2 Create the property node in a new VI or in an existing VI 3 Open the block diagram view 4 From the Functions toolbox select All Functions NI Measurements DAQmx Data Acquisition and select DAQm x Channel Property Node 5 Left click inside the Property box and select Active Channels to specify the channel s you want to configure If you want to configure several channels with different properties separate the lists of properties with another Active Channels box and assign the appropriate channel to each list of properties ay Note If you do not use Active Channels the properties are set on all of the channels in the task 6 Right click ActiveChan and select Add Element Left click the new ActiveChan box Navigate throu
55. powered on they are again enabled and the red X is removed To completely remove a module or the entire chassis right click the module or chassis and then click Delete The SCXI 1600 module is now removed from the list of installed devices in MAX C 2 ni com Common Questions This appendix contains answers to commonly asked questions about the operation and special features of the SCXI 1600 module How do I know if my version of Windows supports USB Open the System properties in the Control Panel Select the Hardware tab and click the Device Manager button if a Universal Serial Bus Controller along with a USB controller and a USB root hub are listed If the computer has this and USB ports the computer supports USB If the computer has USB ports but no controller is listed in the Device Manager you must upgrade your software What is the best way to test the SCXI 1600 without having to program the module The SCXI 1600 has no Test Panels but you can perform a Test Chassis to verify the presence of the SCXI 1600 What do the different LED patterns on the front panel mean The top two green LEDs indicate whether you have power to the SCXI chassis backplane while the bottom two LEDs indicate USB communication Refer to Table 1 1 LED Patterns for SCXI 1600 USB States for more information If either of the top two green LEDs is off check the fuses in the back of the SCXI chassis What are PFIs and how do I configure t
56. r line motors generators transformers fluorescent lights soldering irons CRT displays computers electrical storms welders radio transmitters and internal sources such as semiconductors resistors and capacitors Noise corrupts signals you are trying to send or receive a measure of signal amplitude the difference between the highest and lowest excursions of the signal programmable function input programmable gain instrumentation amplifier hardware or software that after being installed can immediately be used as opposed to hardware or software that requires configuration 1 a digital port consisting of multiple I O lines on a DAQ device 2 a serial or parallel interface connector on a PC an electrical device in which the resistance can be manually adjusted used for manual adjustment of electrical circuits and as a transducer for linear or rotary position parts per million SCXI 1600 User Manual Glossary Q quantization error R relative accuracy resolution rise time rms S s sample clock sample counter scan SCXI 1600 User Manual the inherent uncertainty in digitizing an analog value due to the finite resolution of the conversion process a measure in LSB of the accuracy of an ADC It includes all nonlinearity and quantization errors It does not include offset and gain errors of the circuitry feeding the ADC the smallest signal increment that a measurement system can detect Resolu
57. s NI ADEs have tools that allow you to easily save the data to files such as spread sheets for easy viewing ASCII files for universality or binary files for smaller file sizes Completing the Application After you have completed the measurement analysis and presentation of the data it is important to stop and clear the task This releases any memory used by the task and frees up the DAQ hardware for use in another task Developing an Application Using LabVIEW This section describes in more detail the steps shown in the typical program flowchart in Figure 4 1 such as how to create a task in LabVIEW If you need more information or instructions select Help VI Function amp How To Help from the LabVIEW menu bar National Instruments Corporation 4 5 SCXI 1600 User Manual Chapter 4 3 Using the SCXI 1600 Note Except where otherwise stated the VIs in Table 4 1 are located on the Functions All Functions NI Measurements DAQm x Data Acquisition subpalette and accompanying subpalettes in LabVIEW Table 4 1 Programming a Task in LabVIEW Flowchart Step VI or Program Step Create a Task in the DAQ Assistant Create a Task located on the Functions Input subpalette DAQ Assistant Create a Task The DAQmx Create Task VI is optional if you created and configured Programmatically your task using the DAQ Assistant However if you use it in LabVIEW optional any changes you make to the task
58. s accurate The document has been carefully reviewed for technical accuracy In the event that technical or typographical errors exist National Instruments reserves the right to make changes to subsequent editions of this document without prior notice to holders of this edition 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 EXCEPT AS SPECIFIED HEREIN NATIONAL INSTRUMENTS MAKES NO WARRANTIES EXPRESS OR IMPLIED AND SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE CUSTOMER S RIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER NATIONAL INSTRUMENTS WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA PROFITS USE OF PRODUCTS OR INCIDENTAL OR CONSEQUENTIAL DAMAGES EVEN IF ADVISED OF THE POSSIBILITY THEREOF This limitation of the liability of National Instruments will apply regardless of the form of action whether in contract or tort including negligence Any action against National Instruments must be brought within one year after the cause of action accrues National Instruments shall not be liable for any delay in performance due to causes beyond its reasonable control The warranty provided herein does not cover damages defects malfunc
59. s follows e The top two green LEDs which monitor the V and V rails of the SCXI chassis backplane must be bright green for the signal conditioning system to function properly If either or both the V or V green LEDs is off check the SCXI chassis backplane fuses and replace any bad fuses as described in the SCXT Chassis User Manual e The bottom two LEDs the yellow ACTIVE LED and green READY LED indicate the state of the SCXI 1600 USB If the READY LED is bright green the SCXI 1600 is powered connected to the host and is configured properly Refer to Table 1 1 for LED pattern descriptions 1 4 ni com Chapter 1 About the SCXI 1600 Table 1 1 LED Patterns for SCXI 1600 USB States ACTIVE READY Yellow LED Green LED Description Off Off The SCXI 1600 is not powered Off On The SCXI 1600 is configured but there is no activity over the bus On On The SCXI 1600 is configured and there is activity over the bus Blinking On Off Blinking The SCXI 1600 is being configured but there is no activity over the bus On Blinking The SCXI 1600 is being configured and there is activity over ee ea the bus Blinking Blinking Blinking continuously This indicates a recoverable error state in the SCXI 1600 You can power off the module or detach and reattach the USB cable to reset the module Blinking alternately This indicates an unrecoverable error in the SCXI 1600 Refer to the Signal Conditioning Technica
60. seeseereereerreeereee USB Configuration memory Size 512 words Max working voltage signal common mode eeeeeeeeee Each input should remain within 11 V of ground External calibration overvoltage protection Powered OM se ciciseesisietine 25 V Powered off 15 V National Instruments Corporation A 1 SCXI 1600 User Manual Appendix A Specifications Accuracy Information Absolute Accuracy Noise Absolute Relative Accuracy Nominal of Reading Quantization uV Accuracy Resolution uV Range Temp at Full at Full Offset Single Drift Scale Single Scale V 24 Hours 1 Year uV Point Averaged 0 mV Point Averaged 10 0 0546 0 0588 1601 1029 92 0 0010 7 57 1205 121 5 0 0146 0 0188 811 515 46 0 0005 1 80 603 60 3 0 5 0 0546 0 0588 100 66 6 0 0010 0 40 78 4 7 9 0 05 0 0546 0 0588 29 31 3 0 0 0010 0 061 39 8 4 0 Note Accuracies are valid for measurements following an internal calibration Averaged numbers assume dithering and averaging of 100 single channel readings Measurement accuracies are listed for operational temperatures within 1 C of internal calibration temperature and 10 C of external or factory calibration temperature SCXI 1600 User Manual Transfer Characteristics Integral nonlinearity INL 1 5 LSB typ 2 0 LSB max Differential nonlinearity DNL 0 5 LSB typ 3 0 LSB max No missing
61. signals with A D and or DIO boards plugged into a computer and possibly generating control signals with D A and or DIO boards in the same computer decibel the unit for expressing a logarithmic measure of the ratio of two signal levels dB 20log10 V1 V2 for signals in volts direct current a default parameter value recorded in the driver In many cases the default input of a control is a certain value often 0 that means use the current default setting For example the default input for a parameter may be do not change current setting and the default setting may be no AMUX 64T boards If you do change the value of such a parameter the new value becomes the new setting You can set default settings for some parameters in the configuration utility or manually using switches located on the device a plug in data acquisition board module card or pad that can contain multiple channels and conversion devices SCXI modules are distinct from devices with the exception of the SCXI 1600 which is a hybrid differential mode the two terminal input to a differential amplifier See port digital input output the addition of Gaussian noise to an analog input signal G 4 ni com DNL drivers driver software E EMC event external trigger F FIFO filtering G gain gain accuracy GATE input pin grounded source H T O ID National Instruments Corporation G 5 Glossary differential nonlinearity a m
62. ss Two Conversions per Scan Figure B 8 Al CONV CLK Input Signal Timing The ADC switches to hold mode within 60 ns of the selected edge This hold mode delay time is a function of temperature and does not vary from one conversion to the next Separate the AI CONV CLK pulses by at least one conversion period B 8 ni com Appendix B Timing Signal Information The sample interval counter on the SCXI 1600 module normally generates the AI CONV CLK signal unless you select an external source The counter is started by the AI SAMP CLK signal and continues to count down and reload itself until the scan is finished It then reloads itself in readiness for the next AI SAMP CLK pulse A D conversions generated by either an internal or external AICONV CLK signal are inhibited unless they occur within a data acquisition sequence Either the hardware AI GATE signal or software command register gate can gate scans occurring within a data acquisition sequence Al GATE Signal Any PFI pin can externally input the AI GATE signal The AI GATE signal can mask off scans in a data acquisition sequence You can configure the PFI pin you select as the source for the AI GATE signal in either the level detection or edge detection mode You can configure the polarity selection for the PFI pin for either active high or active low In the level detection mode if AI GATE is active the AI SAMP CLK signal is masked off and no scans can occur In the edge
63. tage relative to the ground of the computer of the signals from a differential input any voltage present at the instrumentation amplifier inputs with respect to amplifier ground device that transforms a signal from one form to another For example analog to digital converters ADCs for analog input digital to analog converters DACs for analog output digital input or output ports and counter timers are conversion devices the time required in an analog input or output system from the moment a channel is interrogated such as with a read instruction to the moment that accurate data is available clock signal used to increment to the next channel after each DAQ device analog to digital conversion a circuit that counts external pulses or clock pulses timing the manner in which a signal is connected from one location to another SCXI 1600 User Manual Glossary D A D GND DAC DAQ dB DC default setting device DIFF differential input digital port DIO dithering SCX I 1600 User Manual digital to analog digital ground signal D A converter an electronic device often an integrated circuit that converts a digital number into a corresponding analog voltage or current data acquisition 1 collecting and measuring electrical signals from sensors transducers and test probes or fixtures and processing the measurement data using a computer 2 collecting and measuring the same kinds of electrical
64. tion is expressed in bits in proportions or in percent of full scale For example a system has 12 bit resolution one part in 4 096 resolution and 0 0244 of full scale resolution the difference in time between the 10 and 90 points of a system step response root mean square the square root of the average value of the square of the instantaneous signal amplitude a measure of signal amplitude seconds samples samples per second used to express the rate at which a DAQ board samples an analog signal the clock controlling the time interval between samples of all channels the clock that counts the output of the channel clock in other words the number of samples taken On boards with simultaneous sampling this counter counts the output of the scan clock and hence the number of scans one or more analog samples taken at the same time or nearly the same time Typically the number of input samples in a scan is equal to the number of channels in the input group For example one scan acquires one new sample from every analog input channel in the group G 8 ni com scan rate SCXI sensor settling time SI SOURCE signal conditioning software trigger source impedance STC successive approximation ADC switchless device system noise T TC THD transducer transducer excitation National Instruments Corporation G 9 Glossary the number of scans a system takes during a given time period usually
65. tion to minimize the effects of any offset and gain drifts particularly those due to warming You must perform the internal calibration within 24 hours of the measurement to meet the 24 hour accuracy specifications provided in Appendix A Specifications Immediately after internal calibration the only significant residual calibration error could be gain error due to time or temperature drift of the onboard voltage reference This error is addressed by external calibration which is discussed in the External Calibration section If you are interested primarily in relative measurements you can ignore a small amount of gain error and internal calibration should be sufficient Internal Calibration Using MAX Complete the following steps to perform an internal calibration 1 Open MAX 2 Expand Devices and Interfaces 3 Expand NI DAQm x Devices 4 Right click SCXI 1600 5 Select Self Calibrate The software informs you when the internal calibration is complete and whether it was successful Internal Calibration Using LabVIEW 3 SCXI 1600 User Manual Complete the following steps to perform an internal calibration of the SCXI 1600 1 Open a blank block diagram in LabVIEW 2 Select Functions All Functions NI Measurements DAQm x Data Acquisition DAQmx Advanced DAQm x Calibration DAQm x Self Calibrate vi 3 Double click the icon to open the DAQmx Self Calibrate vi Front Panel 4 Inthe device in drop down b
66. tions or service failures caused by owner s failure to follow the National Instruments installation operation or maintenance instructions owner s modification of the product owner s abuse misuse or negligent acts and power failure or surges fire flood accident actions of third parties or other events outside reasonable control Copyright Under the copyright laws this publication may not be reproduced or transmitted in any form electronic or mechanical including photocopying recording storing in an information retrieval system or translating in whole or in part without the prior written consent of National Instruments Corporation Trademarks CVI DAQ STC LabVIEW Measurement Studio National Instruments NI ni com NI DAQ and SCXI are trademarks of National Instruments Corporation Product and company names mentioned herein are trademarks or trade names of their respective companies Patents For patents covering National Instruments products refer to the appropriate location Help Patents in your software the patents txt file on your CD or ni com patents WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS 1 NATIONAL INSTRUMENTS PRODUCTS ARE NOT DESIGNED WITH COMPONENTS AND TESTING FOR A LEVEL OF RELIABILITY SUITABLE FOR USE IN OR IN CONNECTION WITH SURGICAL IMPLANTS OR AS CRITICAL COMPONENTS IN ANY LIFE SUPPORT SYSTEMS WHOSE FAILURE TO PERFORM CAN REASONABLY BE EXPECTED TO CAU
67. tiplexing operation of the analog input signals is performed entirely by multiplexers in the SCXI modules not inside the SCXI 1600 or SCXI chassis In multiplexed mode the SCXI module channels you are scanning are kept by the NI DAQ driver in a scan list Immediately prior to a multiplexed scanning operation the SCXI chassis is programmed with a module scan list that controls which module sends its output to the SCXIbus during a scan to the SCXI 1600 The list can contain channels in any physical order and the multiplexer can sequence the channel selection from the scan list in any order The ordering of scanned channels need not be sequential Channels can occur multiple times in a single scan list The scan list can contain an arbitrary number of channels for each module entry in the scan list limited to a total of 352 channels per SCXI 1600 This is referred to as flexible scanning random scanning Not all SCXI modules provide flexible scanning National Instruments Corporation 3 5 SCXI 1600 User Manual Chapter 3 Theory of Operation SCX I 1600 User Manual The analog input modules include first in first out FIFO memory for storing the channel scan list defined in your application code NI DAQ drivers load the FIFO based on the channel assignments you make in your application You need not explicitly program the module FIFO as this is done automatically for you by the NI DAQ driver 3 6 ni com Using the SCXI 1600 Th
68. to the National Instruments Web site at ni com info and enter the info code feedback 2004 National Instruments Corporation All rights reserved Important Information Warranty The SCXI 1600 is warranted against defects in materials and workmanship for a period of one year from the date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace equipment that proves to be defective during the warranty period This warranty includes parts and labor The media on which you receive National Instruments software are warranted not to fail to execute programming instructions due to defects in materials and workmanship for a period of 90 days from date of shipment as evidenced by receipts or other documentation National Instruments will at its option repair or replace software media that do not execute programming instructions if National Instruments receives notice of such defects during the warranty period National Instruments does not warrant that the operation of the software shall be uninterrupted or error free A Return Material Authorization RMA number must be obtained from the factory and clearly marked on the outside of the package before any equipment will be accepted for warranty work National Instruments will pay the shipping costs of returning to the owner parts which are covered by warranty National Instruments believes that the information in this document i
69. ut they also apply to signal routing in general Take the following precautions to minimize noise pickup and maximize measurement accuracy e For the external calibration signals make connections using individually shielded twisted pair wires With this type of wire the signals attached to the CH and CH inputs are twisted together and then covered with a shield You then connect this shield only at one point to the signal source ground This kind of connection is required for signals traveling through areas with large magnetic fields or high electromagnetic interference e Route signals to the device carefully Keep cabling away from noise sources The most common noise source in a computer DAQ system is the video monitor Separate the monitor from the analog signals as much as possible The following recommendations apply to all signal connections to the SCXI 1600 module e Separate SCXI 1600 module signal lines from high current or high voltage lines These lines are capable of inducing currents in or voltages on the SCXI 1600 module signal lines if they run in parallel paths at a close distance To reduce the magnetic coupling between lines that run in parallel separate them as much as possible or run the lines perpendicular to each other e Do not run signal lines through conduits that also contain power lines e Protect signal lines from magnetic fields caused by electric motors welding equipment breakers or transformers by
70. veloping your application properties configuring channel properties 4 5 NI DAQmx programmable properties 4 9 property node DAQmx Channel Property Node 4 6 pullup and pulldown resistor tolerance 2 4 R random scanning See flexible scanning range 3 2 selecting input ranges 3 3 range and measurement precision table 3 2 READY LED 1 5 2 2 regulatory compliance specifications A 7 removing the SCX I 1600 C 1 resistor tolerance table note 2 4 resolution A 1 S safety specifications A 6 SAMP CLK signal 2 3 sampling rate A 1 scan rate calculating the maximum 3 3 scanning considerations 3 3 flexible 3 5 SCXI chassis installing SCXI 1600 1 4 SCXI 1600 about the module 1 1 cabling between computer USB port or USB hub figure 2 1 calibration 4 9 SCXI 1600 User Manual l 4 front panel connectors figure 2 2 installing 1 4 module block diagram figure 3 1 multiplexed mode of operation 2 4 programming See developing your application removing C 1 specifications A 1 specifying channel strings 4 8 taking measurements See measurements theory of operation 3 1 selecting polarity B 2 selection 3 5 sequencing channel 3 5 settling time 3 3 specifications A 3 SI SOURCE signal B 9 SI SOURCE signal timing figure B 10 signal summary table 2 4 signals AI CONV CLK routing figure 3 4 AI CONV CLK signal B 8 AI CONV CLK signal timing figure B 8 AI GATE signal B 9 AI REF TRIG sig
71. yte of data a voltage range spanning both positive and negative voltages a type of coaxial signal connector temporary storage for acquired or generated data software the group of conductors that interconnect individual circuitry in a computer Typically a bus is the expansion interface to which I O or other devices are connected G 2 ni com C C channel channel clock circuit trigger clock CMRR code width common mode range common mode signal common mode voltage conversion device conversion time convert clock counter timer coupling National Instruments Corporation G 3 Glossary Celsius pin or wire lead to which you apply or from which you read an analog or digital signal Analog signals can be single ended or differential For digital signals channels are grouped to form ports the clock controlling the time interval between individual channel sampling within a scan Boards with simultaneous sampling do not have this clock a condition for starting or stopping clocks hardware component that controls timing for reading from or writing to groups common mode rejection ratio a measure of the ability of a differential amplifier to reject interference from a common mode signal usually expressed in decibels dB the smallest input voltage change that can be measured by a DAQ device the input range over which a circuit can handle a common mode signal the mathematical average vol

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