National Instruments DAQCard-1200 Chapter 4 Theory of Operation

Contents
DAQCard-1200 User Manual vi © National Instruments Corporation
Types of Signal Sources...................................................................3-6
Floating Signal Sources......................................................3-6
Ground-Referenced Signal Sources................................... 3-6
Input Configurations.........................................................................3-7
Differential Connection Considerations
(DIFF Configuration)......................................................3-7
Differential Connections for Grounded Signal Sources.....3-8
Differential Connections for Floating Signal Sources....... 3-9
Single-Ended Connection Considerations..........................3-11
Single-Ended Connections for Floating Signal Sources
(RSE Configuration)........................................................3-11
Single-Ended Connections for Grounded Signal
Sources (NRSE Configuration).......................................3-12
Common-Mode Signal Rejection Considerations..............3-13
Analog Output Signal Connections.................................................................3-14
Digital I/O Signal Connections.........................................................3-15
Port C Pin Connections.....................................................................3-17
Timing Specifications.......................................................................3-18
Mode 1 Input Timing......................................................... 3-19
Mode 1 Output Timing.......................................................3-20
Mode 2 Bidirectional Timing.............................................3-20
DAQ and General-Purpose Timing Signal Connections................................ 3-22
DAQ Timing Connections................................................................3-22
General-Purpose Timing Signal Connections.................................. 3-26
Power Connections.........................................................................................3-31
Chapter 4
Theory of Operation
Functional Overview.....................................................................................................4-1
PC Card I/O Channel Interface Circuitry...................................................................... 4-2
Timing...........................................................................................................................4-3
Analog Input..................................................................................................................4-5
Analog Input Circuitry....................................................................................4-6
Data Acquisition Timing.................................................................................4-8
Data Acquisition Operation..............................................................4-8
Continuous Data Acquisition............................................................4-8
Interval Data Acquisition..................................................................4-9
Data Acquisition Rates....................................................................................4-9