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© National Instruments Corporation
4-1
DAQCard-500 User Manual
Chapter 4
Theory of Operation
This chapter includes an overview of the DAQCard-500 and explains the operation of each
functional unit making up the DAQCard-500.
Functional Overview
The block diagram in Figure 4-1 shows a functional overview of the DAQCard-500.
From A/D FIFO
I/O Connector
OUT0
EXTCONV*
1 MHz
4
4
-12 V
To Analog Circuit
+5 V
+5 V
+12 V
12-Bit
Sampling
ADC
16-Word
FIFO
PCMCIA
I/O
Channel
Interface
Buffer
PCMCIA
I/O Channel
Scanning Counter
A/D Timing
MSM82C54
Interrupt
Interface
Digital
I/O
DC-DC
Converter
To Analog Circuit
Input
Mux
8-Channel
Single-
Ended
8
+5.1 V
-5.1 V
GATE2
CLK <1..2>
OUT <1..2>
1 A Resettable Fuse
Figure 4-1. DAQCard-500 Block Diagram