National Instruments NI 6232 - Manual (Page 7)

Contents
NI 6232/6233 User Manual viii ni.com
Chapter 3
Connector Information
I/O Connector Signal Descriptions................................................................................ 3-1
RTSI Connector Pinout ................................................................................................. 3-3
Chapter 4
Analog Input
Analog Input Circuitry .................................................................................................. 4-1
Analog Input Range....................................................................................................... 4-2
Analog Input Ground-Reference Settings ..................................................................... 4-3
Configuring AI Ground-Reference Settings in Software ................. 4-5
Multichannel Scanning Considerations ......................................................................... 4-6
Use Low Impedance Sources .......................................................................... 4-6
Use Short High-Quality Cabling..................................................................... 4-7
Carefully Choose the Channel Scanning Order .............................................. 4-7
Avoid Switching from a Large to a Small Input Range ................... 4-7
Insert Grounded Channel between Signal Channels ........................ 4-8
Minimize Voltage Step between Adjacent Channels ....................... 4-8
Avoid Scanning Faster Than Necessary ......................................................... 4-9
Example 1 ......................................................................................... 4-9
Example 2 ......................................................................................... 4-9
Analog Input Data Acquisition Methods....................................................................... 4-9
Software-Timed Acquisitions ......................................................................... 4-9
Hardware-Timed Acquisitions ........................................................................ 4-10
Buffered ............................................................................................ 4-10
Non-Buffered.................................................................................... 4-11
Analog Input Triggering................................................................................................ 4-11
Connecting Analog Voltage Input Signals .................................................................... 4-11
Types of Signal Sources ................................................................................................ 4-12
Floating Signal Sources .................................................................................. 4-13
Ground-Referenced Signal Sources ................................................................ 4-13
Differential Connection Considerations.......................................................... 4-13
Differential Connections for Ground-Referenced Signal Sources.................. 4-14
Differential Input Biasing ................................................................. 4-15
Differential Connections for Non-Referenced or Floating Signal Sources .... 4-15
Single-Ended Connection Considerations ...................................................... 4-16
Single-Ended Connections for Floating or
Grounded Signal Sources............................................................... 4-17
Field Wiring Considerations.......................................................................................... 4-18
Analog Input Timing Signals ........................................................................................ 4-19
AI Sample Clock Signal.................................................................................. 4-22
Using an Internal Source .................................................................. 4-23