User`s guide

ii • Table of Contents
Chapter 4 Operation Theory ................................................24
4.1 A/D Conversion............................................................... 24
4.1.1 DAQ/PXI-2204 AI Data Format ................................................ 25
4.1.1.1 Synchronous Digital Inputs (for DAQ/PXI-2204 only) ............. 25
4.1.2 DAQ/PXI-2205/2206 AI Data Format ...................................... 27
4.1.3 Software conversion with polling data transfer acquisition
mode (Software Polling) ............................................................................ 28
4.1.3.1 Specifying Channels, Gains, and input configurations in the
Channel Gain Queue ................................................................. 28
4.1.4 Programmable scan acquisition mode ....................................... 29
4.1.4.1 Scan Timing and Procedure...................................................... 29
4.1.4.2 Specifying Channels, Gains, and input configurations in the
Channel Gain Queue ................................................................. 31
4.1.4.3 Trigger Modes ........................................................................... 32
4.1.4.4 Bus-mastering DMA Data Transfer .......................................... 38
4.2 D/A Conversion............................................................... 40
4.2.1 Software Update............................................................................ 41
4.2.2 Timed Waveform Generation ..................................................... 41
4.2.2.1 Trigger Modes ........................................................................... 43
4.2.2.2 Iterative Waveform Generation................................................. 45
4.2.2.3 Stop Modes of Scan Update....................................................... 46
4.3 Digital I/O....................................................................... 48
4.4 General Purpose Timer/Counter Operation ........................ 49
4.4.1 Timer/Counter functions basics.................................................. 49
4.4.2 General Purpose Timer/Counter modes .................................... 49
4.4.2.1 Mode1: Simple Gated-Event Counting...................................... 50
4.4.2.2 Mode2: Single Period Measurement ......................................... 50
4.4.2.3 Mode 3: Single Pulse-width Measurement................................ 51
4.4.2.4 Mode 4: Single Gated Pulse Generation................................... 51
4.4.2.5 Mode5: Single Triggered Pulse Generation .............................52
4.4.2.6 Mode6: Re-triggered Single Pulse Generation ......................... 52
4.4.2.7 Mode7: Single Triggered Continuous Pulse Generation .......... 53
4.4.2.8 Mode8: Continuous Gated Pulse Generation ........................... 53