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Chapter 2
Function Reference — Lab_ISCAN_Start
NI-DAQ FRM for PC Compatibles
2-270
©
 National Instruments Corporation
Lab_ISCAN_Start
Format
status = Lab_ISCAN_Start (deviceNumber, numChans, gain, buffer, count, sampTimebase, 
sampInterval, scanInterval)
Purpose
Initiates a multiple-channel scanned data acquisition operation and stores its input in an array 
(DAQCard-500/700 and 516, Lab and 1200 Series, and LPM devices only).
Parameters
Input
Output
Parameter Discussion
numChans is the number of channels to be scanned in a single scan sequence. The value 
of this parameter also determines which channels NI-DAQ scans because these supported 
devices have a fixed scanning order. The scanned channels range from numChans – 1 to 
channel 0. If you are using SCXI modules with additional multiplexers, you must scan the 
appropriate analog input channels on the DAQ device that corresponds to the SCXI channels 
you want. You should select the SCXI scan list using 
SCXI_SCAN_Setup
 before you call this 
function. Refer to Chapter 12, SCXI Hardware, in the DAQ Hardware Overview Guide and 
Name
Type
Description
deviceNumber
i16
assigned by configuration utility
numChans
i16
number of channels to be scanned
gain
i16
gain setting
count
u32
total number of samples to be acquired
sampTimebase
i16
timebase, or resolution, used for the 
sample-interval counter
sampInterval
u16
length of the sample interval
scanInterval
u16
length of the scan interval
Name
Type
Description
buffer
[i16]
results of the scanned data acquisition