National Instruments E Series - Manual (Page 24)

Chapter 3 Hardware Overview
DAQCard E Series User Manual 3-2  National Instruments Corporation
Figure 3-2 shows a block diagram for the DAQCard-AI-16XE-50.
Analog Input
The analog input section of each DAQCard is software configurable.
You can select different analog input configurations through
application software designed to control the DAQCards. The following
sections describe in detail each of the analog input categories.
Input Mode
The DAQCards have three different input modes—nonreferenced
single-ended (NRSE) input, referenced single-ended (RSE) input, and
differential (DIFF) input. The single-ended input configurations use up
to 16 channels. The DIFF input configuration uses up to eight channels.
Input modes are programmed on a per channel basis for multimode
scanning. For example, you can configure the circuitry to scan 12
channels—four differentially configured channels and eight
Figure 3-2. DAQCard-AI-16XE-50 Block Diagram
Timing
PFI / Trigger
I/O Connector
3
2
PCMCIA Connector
Digital I/O (8)
16-Bit
Sampling
A/D
Converter
Configuration
Memory
+
Programmable
Gain
Amplifier
–
Calibration
Mux
Mux Mode
Selection
Switches
Analog
Muxes
Voltage
REF
Calibration
DACs
DAQ - STC
Analog Input
Timing/Control
Analog Output
Timing/Control Digital I/O
Trigger
Counter/
Timing I/O
RTSI Bus
Interface
DMA/
Interrupt
Request
Bus
Interface
(8)
(8)
AI Control
Data (16)
Analog
Input
Control
EEPROM
Control
DMA
Interface
DAQ-PCMCIA
DAQ-STC
Bus
Interface
Analog
Output
Control Bus
Interface
IRQ
DMA
Data
Transceivers
ADC
FIFO
EEPROM