Resumen del contenido incluido en la página 1
Computer-Based
Instruments
NI 5911 User Manual
™
High-Speed Digitizer with FLEX ADC
NI 5911 User Manual
June 2001 Edition
Part Number 322150D-01
Resumen del contenido incluido en la página 2
Support Worldwide Technical Support and Product Information ni.com National Instruments Corporate Headquarters 11500 North Mopac Expressway Austin, Texas 78759-3504 USA Tel: 512 794 0100 Worldwide Offices Australia 03 9879 5166, Austria 0662 45 79 90 0, Belgium 02 757 00 20, Brazil 011 284 5011, Canada (Calgary) 403 274 9391, Canada (Montreal) 514 288 5722, Canada (Ottawa) 613 233 5949, Canada (Québec) 514 694 8521, Canada (Toronto) 905 785 0085, China (Shanghai) 021 6555 7838, China (ShenZhen)
Resumen del contenido incluido en la página 3
Important Information Warranty The NI 5911 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 d
Resumen del contenido incluido en la página 4
Compliance FCC/Canada Radio Frequency Interference Compliance* Determining FCC Class The Federal Communications Commission (FCC) has rules to protect wireless communications from interference. The FCC places digital electronics into two classes. These classes are known as Class A (for use in industrial-commercial locations only) or Class B (for use in residential or commercial locations). Depending on where it is operated, this product could be subject to restrictions in the FCC rules. (In Canad
Resumen del contenido incluido en la página 5
Canadian Department of Communications This Class B digital apparatus meets all requirements of the Canadian Interference-Causing Equipment Regulations. Cet appareil numérique de la classe B respecte toutes les exigences du Règlement sur le matériel brouilleur du Canada. Compliance to EU Directives Readers in the European Union (EU) must refer to the Manufacturer's Declaration of Conformity (DoC) for information** pertaining to the CE Mark compliance scheme. The Manufacturer includes a DoC for mo
Resumen del contenido incluido en la página 6
Conventions The following conventions are used in this manual: » The » symbol leads you through nested menu items and dialog box options to a final action. The sequence File»Page Setup»Options directs you to pull down the File menu, select the Page Setup item, and select Options from the last dialog box. This icon denotes a note, which alerts you to important information. This icon denotes a caution, which advises you of precautions to take to avoid injury, data loss, or a system crash. bold Bol
Resumen del contenido incluido en la página 7
Contents Chapter 1 Taking Measurements with the NI 5911 Installing the NI 5911 ....................................................................................................1-1 Connecting Signals ........................................................................................................1-1 Acquiring Data with Your NI 5911 ...............................................................................1-3 Programmatically Controlling Your NI 5911.................................
Resumen del contenido incluido en la página 8
Contents RTSI Bus and Clock PFI ............................................................................................... 2-11 PFI Lines......................................................................................................... 2-11 PFI Lines as Inputs ........................................................................... 2-12 PFI Lines as Outputs......................................................................... 2-12 Synchronization ...............................
Resumen del contenido incluido en la página 9
1 Taking Measurements with the NI 5911 Thank you for buying a National Instruments (NI) 5911 digitizer, featuring the FLEX ADC. This chapter provides information on installing, connecting signals to, and acquiring data from your NI 5911. Installing the NI 5911 There are two main steps involved in installation: 1. Install the NI-SCOPE driver software. You use this driver to write programs to control your NI 5911 in different application development environments (ADEs). Installing NI-SCOPE also al
Resumen del contenido incluido en la página 10
Chapter 1 Taking Measurements with the NI 5911 CH0 PFI1 PFI2 (DIN) Figure 1-1. NI 5911 Connectors 9 8 7 6 5 4 3 2 1 1 +5 Volts (Fused) 4Reserved 7 Reserved 2GND 5Reserved 8 Reserved 3 Reserved 6PFI2 9 Reserved Figure 1-2. 9-Pin Mini Circular DIN Connector NI 5911 User Manual 1-2 ni.com
Resumen del contenido incluido en la página 11
Chapter 1 Taking Measurements with the NI 5911 Acquiring Data with Your NI 5911 You can acquire data either programmatically—by writing an application foryourNI5911—or interactively with the Scope Soft Front Panel. Programmatically Controlling Your NI 5911 To help you get started programming your NI 5911, NI-SCOPE comes with examples that you can use or modify. You can find examples for these different ADEs: LabVIEW—Go toProgram Files\National Instruments\ LabVIEW\Examples\Instr\niScopeExample
Resumen del contenido incluido en la página 12
2 Hardware Overview This chapter includes an overview of the NI 5911, explains the operation of each functional unit making up your NI 5911, and describes the signal connections. Figure 2-1 shows a block diagram of the NI 5911. Analog Input AC/DC Coupling Connector Protect/ Calibration PGIA A/D Converter Mux 100 MHz, 8-Bit Noise Shaper Calibration Generator Timing IO/ Reference Digital IO Memory Control Clock Connector Digital Signal Capture Processor Memory Data Figure 2-1. NI 5911 Block Diagra
Resumen del contenido incluido en la página 13
Chapter 2 Hardware Overview Differential Input When measuring high dynamic range signals, ground noise is often a problem. The PGIA of the NI 5911 allows you to make noise-free signal measurements. The PGIA differential amplifier efficiently rejects any noise present on the ground signal. Internal to the PGIA, the signal presented at the negative input is subtracted from the signal presented at the positive input. As shown in Figure 2-2, this subtraction removes ground noise from the signal. The
Resumen del contenido incluido en la página 14
Chapter 2 Hardware Overview Input Ranges To optimize the ADC resolution, you can select different gains for the PGIA. In this way, you can scale your input signal to match the full input range of the converter. The NI 5911 PGIA offers seven different input ranges, from ±0.1 V to ±10 V, as shown in Table 2-1. Table 2-1. Input Ranges for the NI 5911 Range Input Protection Threshold ±10 V ±10 V ±5 V ±5 V ±2 V ±5 V ±1 V ±5 V ±0.5 V ±5 V ±0.2 V ±5 V ±0.1 V ±5 V Note If you try to acquire a signal bel
Resumen del contenido incluido en la página 15
Chapter 2 Hardware Overview if the device has 1 MΩ output impedance, your measured signal will be one-half the actual signal value. Input Bias The inputs of the PGIA typically draw an input bias current of 1 nA at 25 °C. Attaching a device with a very high source impedance can cause an offset voltage to be added to the signal you measure, according to the formula R ×1nA,where R is the external source impedance. For s s example, if the device you have attached to the NI 5911 has an output impedan
Resumen del contenido incluido en la página 16
Chapter 2 Hardware Overview analysis, distortion analysis, and other measurements for which high resolution is crucial. Oscilloscope Mode The ADC converts at a constant rate of 100 MS/s, but you can choose to store only a fraction of these samples into memory at a lower rate. This allows you to store waveforms using fewer data points and decreases the burden of storing, analyzing, and displaying the waveforms. If you need faster sampling rates, you can use Random Interleaved Sampling (RIS) to ef
Resumen del contenido incluido en la página 17
Chapter 2 Hardware Overview Table 2-2. Available Sampling Rates and Corresponding Bandwidth in Flexible Resolution Mode Sampling Rate Resolution Bandwidth 12.5 MS/s 11 Bits 3.75 MHz 5MS/s 14 Bits 2MHz 2.5 MS/s 15.5 Bits 1MHz 1MS/s 17.5 Bits 400 kHz 500 kS/s 18 Bits 200 kHz 200 kS/s 18.5 Bits 80 kHz 100 kS/s 19 Bits 40 kHz 50 kS/s 19.5 Bits 20 kHz 20 kS/s 20.5 Bits 8kHz 10 kS/s 21 Bits 4kHz Like any other type of converter that uses noise shaping to enhance resolution, the frequency response of t
Resumen del contenido incluido en la página 18
Chapter 2 Hardware Overview Calibration The NI 5911 can be calibrated for very high accuracy and resolution due to an advanced calibration scheme. There are two different types of calibration: internal, or self, calibration and external calibration. A third option, internal restore, restores factory settings and should be used only in the event of a self-calibration failure. Internal calibration is performed via a software command that compensates for drifts caused by environmental temperature c
Resumen del contenido incluido en la página 19
Chapter 2 Hardware Overview The linearity of the ADC is calibrated using an internal sinewave generator as reference. The time-to-digital converter used for RIS measurements is calibrated. Caution Do not apply high-amplitude or high-frequency signals to the NI 5911 during internal calibration. For optimal calibration performance, disconnect the input signal from the NI 5911. Why Errors Occur During Acquisition The NI 5911 uses a heater circuit to maintain constant temperature on the critical
Resumen del contenido incluido en la página 20
Chapter 2 Hardware Overview High Analog + Level COMP Input Gain Analog ATC_OUT Trigger Circuit COMP Low – Level a. Analog Trigger Circuit Software ATC_OUT Trigger RTSI <0..6> 7 PFI1, PFI2 2 Arm b. Trigger and Arm Sources Figure 2-3. Trigger Sources Analog Trigger Circuit The analog trigger on the NI 5911 operates by comparing the current analog input to an onboard threshold voltage. This threshold voltage is the trigger value, and can be set within the current input range in 170 steps. This mean
