National Instruments Low-Cost Multifunction I/O Board for ISA Lab-PC+ Chapter 3 Signal Connections , Chapter 4 Theory of Operation

Contents
Lab-PC+ User Manual vi © National Instruments Corporation
Chapter 3
Signal Connections ............................................................................................................ 3-1
I/O Connector Pin Description....................................................................................... 3-1
Signal Connection Descriptions......................................................................... 3-2
Analog Input Signal Connections ...................................................................... 3-4
Types of Signal Sources................................................................................................. 3-5
Floating Signal Sources ..................................................................................... 3-5
Ground-Referenced Signal Sources ................................................................... 3-6
Input Configurations ...................................................................................................... 3-6
Differential Connection Considerations (DIFF Configuration)......................... 3-6
Differential Connections for Grounded Signal Sources .................................... 3-7
Differential Connections for Floating Signal Sources ....................................... 3-8
Single-Ended Connection Considerations ......................................................... 3-10
Single-Ended Connections for Floating Signal Sources
(RSE Configuration) .......................................................................................... 3-10
Single-Ended Connections for Grounded Signal Sources
(NRSE Configuration) ....................................................................................... 3-11
Common-Mode Signal Rejection Considerations.............................................. 3-12
Analog Output Signal Connections.................................................................... 3-12
Digital I/O Signal Connections.......................................................................... 3-13
Port C Pin Connections.......................................................................... 3-15
Timing Specifications ............................................................................ 3-16
Mode 1 Input Timing ............................................................................. 3-18
Mode 1 Output Timing .......................................................................... 3-19
Mode 2 Bidirectional Timing................................................................. 3-20
Timing Connections........................................................................................... 3-21
Data Acquisition Timing Connections................................................... 3-21
General-Purpose Timing Signal Connections and
General-Purpose Counter/Timing Signals ............................................. 3-24
Cabling........................................................................................................................... 3-28
Chapter 4
Theory of Operation .......................................................................................................... 4-1
Functional Overview...................................................................................................... 4-1
PC I/O Channel Interface Circuitry ............................................................................... 4-2
Analog Input and Data Acquisition Circuitry ................................................................ 4-4
Analog Input Circuitry ....................................................................................... 4-5
Data Acquisition Timing Circuitry .................................................................... 4-5
Single-Channel Data Acquisition........................................................... 4-6
Multiple-Channel (Scanned) Data Acquisition...................................... 4-6
Data Acquisition Rates........................................................................... 4-7
Analog Output Circuitry ................................................................................................ 4-9
Digital I/O Circuitry....................................................................................................... 4-10
Timing I/O Circuitry ...................................................................................................... 4-11