User manual

Glossary

scan one or more analog or digital input samples. Typically, the number of input

samples in a scan is equal to the number of channels in the input group. For

example, one pulse from the scan clock produces one scan which acquires

one new sample from every analog input channel in the group.

scan clock the clock controlling the time interval between scans.

SCXI Signal Conditioning eXtensions for Instrumentation—the National

Instruments product line for conditioning low-level signals within an

external chassis near sensors so only high-level signals are sent to DAQ

devices in the noisy PC environment

self-calibrating a property of a DAQ device that has an extremely stable onboard reference

and calibrates its own A/D and D/A circuits without manual adjustments by

the user

settling time the amount of time required for a voltage to reach its final value within

specified limits

signal conditioning the manipulation of signals to prepare them for digitizing

SISOURCE SI counter clock signal

software trigger a programmed event that triggers an event such as data acquisition

SOURCE source signal

STARTSCAN start scan signal

STC system timing controller

TC terminal count—the highest value of a counter

THD total harmonic distortion—the ratio of the total rms signal due to harmonic

distortion to the overall rms signal, in decibel or a percentage

TRIG trigger signal

trigger any event that causes or starts some form of data capture

UM.book Page 11 Monday, May 14, 2001 10:32 AM