National Instruments DAQCard-1200 Calibration

© National Instruments Corporation 5-1 DAQCard-1200 User Manual

5

Calibration

This chapter discusses the calibration procedures for the DAQCard-1200

analog I/O circuitry. However, the DAQCard-1200 is factory calibrated,

and National Instruments can recalibrate your card if necessary. To

maintain the 12-bit accuracy of the DAQCard-1200 analog input and

analog output circuitry, recalibrate at 6-month intervals.

There are two ways to perform calibrations.

• Use the NI-DAQ Calibrate_1200 function. This is the simpler

method.

• Use your own register-level writes to the calibration DACs and the

EEPROM.

The DAQCard-1200 is software calibrated, so there are no calibration

trimpots. The calibration process involves reading offset and gain errors

from the analog input and analog output sections and writing values to the

appropriate calibration DACs to null the errors. There are four calibration

DACs associated with the analog input section and four calibration DACs

associated with the analog output section, two for each output channel.

After the calibration process is complete, each calibration DAC is at a

known value. Because these values are lost when the card is powered down,

they are stored in the onboard EEPROM for future reference.

The factory information occupies one half of the EEPROM and is

write-protected. The lower half of the EEPROM contains user areas for

calibration data. There are four different user areas. When the

DAQCard-1200 is powered on, or when the conditions under which it is

operating change, you must load the calibration DACs with the appropriate

calibration constants.

If you use the DAQCard-1200 with NI-DAQ and LabVIEW or

LabWindows/CVI, the factory calibration constants are automatically

loaded into the calibration DAC the first time a function pertaining to

the DAQCard-1200 is called, and then each time you change your

configuration. You can, instead, choose to load the calibration DACs with

calibration constants from the user areas in the EEPROM, or you can

recalibrate the DAQCard-1200 and load these constants directly into the

calibration DACs.

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