National Instruments DAQCard-1200 - page 46

Chapter 3 Signal Connections

DAQCard-1200 User Manual 3-24 © National Instruments Corporation

Figure3-14 shows a pretrigger data acquisition timing sequence using

EXTTRIG and EXTCONV*. The data acquisition operation has been

initiated through software. Notice that the sample counter has been

programmed to allow five conversions after the rising edge on the

EXTTRIG signal. Additional transitions on the EXTTRIG line have no

effect until you initiate a new data acquisition sequence.

Figure 3-14. Pretrigger DAQ Timing

Because both pretrigger and posttrigger modes use EXTTRIG input, you

can only use one mode at a time.

For interval scanning data acquisition, counter B1 determines the scan

interval. Instead of using counter B1, you can externally time the scan

interval through OUTB1. If you externally time the sample interval, you

should also externally time the scan interval.

Figure3-15 shows an example of a multiple-channel interval-scanning data

acquisition operation. The scan interval and the sample interval are being

timed externally through OUTB1 and EXTCONV*. Channels 1 and 0 of

the input multiplexers are being scanned once during each scan interval.

The first rising edge of EXTCONV* must occur a minimum of 50 ns after

the rising edge on OUTB1. The first rising edge of EXTCONV* after the

rising edge of OUTB1 enables an internal GATE signal that allows

conversions to occur. The first conversion then occurs on the following

falling edge of EXTCONV*.

tw 50 ns minimum

EXTTRIG

EXTCONV*

CONVERT

VIH

VIL

tw

tw

Contents

Main Page Important Information Warranty Copyright Trademarks WARNING REGARDING USE OF NATIONAL INSTRUMENTS PRODUCTS Contents Chapter 4 Theory of Operation Page Tables About This Manual Organization of This Manual Conventions Used in This Manual National Instruments Documentation Related Documentation Introduction About the DAQCard-1200 What You Need to Get Started Software Programming Choices LabVIEW and LabWindows/CVI Application Software NI-DAQ Driver Software Register-Level Programming Optional Equipment Unpacking Installation and Configuration Installation Configuration Analog Input Configuration Analog Input Polarity Analog Input Mode RSE Input (Eight Channels, Default Setting) NRSE Input (Eight Channels) DIFF Input (Four Channels) Analog Output Configuration Analog Output Polarity Digital I/O Configuration Counter Configuration Signal Connections I/O Connector Figure 3-1. DAQCard-1200 I/O Connector Pin Assignments Signal Connection Descriptions Analog Input Signal Connections + Types of Signal Sources Floating Signal Sources Ground-Referenced Signal Sources Input Configurations Differential Connection Considerations (DIFF Configuration) Differential Connections for Grounded Signal Sources Figure 3-3. Differential Input Connections for Grounded Signal Sources Differential Connections for Floating Signal Sources Figure 3-4. Differential Input Connections for Floating Sources Single-Ended Connection Considerations Single-Ended Connections for Floating Signal Sources (RSE Configuration) Single-Ended Connections for Grounded Signal Sources (NRSE Configuration) Common-Mode Signal Rejection Considerations Analog Output Signal Connections Digital I/O Signal Connections Page Port C Pin Connections Timing Specifications Mode 1 Input Timing Mode 1 Output Timing Mode 2 Bidirectional Timing Page DAQ and General-Purpose Timing Signal Connections DAQ Timing Connections Page Page Page General-Purpose Timing Signal Connections Page Page Figure 3-18. Frequency Measurement Application Chapter 3 Signal Connections DAQCard-1200 User Manual 3-30 National Instruments Corporation Figure 3-19. General-Purpose Timing Signals The GATE and OUT signals in Figure3-19 are referenced to the rising edge of the CLK signal. Power Connections National Instruments Corporation 4-1 DAQCard-1200 User Manual Theory of Operation This chapter explains the operation of each functional unit of the DAQCard-1200. Figure 4-1. DAQCard-1200 Block Diagram Functional Overview The block diagram in Figure 4-1 shows a functional overview of the DAQCard-1200. PC Card I/O Channel Interface Circuitry Timing Chapter 4 Theory of Operation Figure 4-3. Timing Circuitry DAQCard-1200 User Manual 4-4 National Instruments Corporation Analog Input Analog Input Circuitry Page Data Acquisition Timing Data Acquisition Operation Continuous Data Acquisition Interval Data Acquisition Data Acquisition Rates Page Analog Output Analog Output Circuitry Power-On State DAC Timing Digital I/O Calibration Calibration at Higher Gains Calibration Equipment Requirements Using the Calibration Function Page A Specifications Analog Input Input Characteristics Transfer Characteristics Amplifier Characteristics Dynamic Characteristics Stability Analog Output Output Characteristics Transfer Characteristics Page Timing I/O Digital Trigger Bus Interface Power Requirement Physical Page B Differences among the Lab-PC+, the DAQPad-1200, and the DAQCard-1200 Page C Power-Management Modes Page D PC Card Questions and Answers Configuration Operation Resources Page Page E Technical Support Resources NI Web Support Online Problem-Solving and Diagnostic Resources Software-Related Resources Worldwide Support Glossary Numbers/Symbols A B C D E F G Page Page V Index Numbers A B C D E F G I L M N O R S T U V W