National Instruments Welding System 321645c-01 Manual De Usuario
Chapter 2
Function Reference — AI_Read
NI-DAQ FRM for PC Compatibles
2-12
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National Instruments Corporation
AI_Read
Format
status = AI_Read (deviceNumber, chan, gain, reading)
Purpose
Reads an analog input channel (initiates an A/D conversion on an analog input channel) and
returns the unscaled result.
returns the unscaled result.
Parameters
Input
Output
Parameter Discussion
chan is the analog input channel number. If you are using SCXI, you must use the appropriate
analog input channel on the DAQ device that corresponds to the SCXI channel you want. To
select the SCXI channel, use
analog input channel on the DAQ device that corresponds to the SCXI channel you want. To
select the SCXI channel, use
SCXI_Single_Chan_Setup
before calling this function. Refer
to Chapter 12, SCXI Hardware, in the DAQ Hardware Overview Guide and the NI-DAQ User
Manual for PC Compatibles for more information on SCXI channel assignments.
Manual for PC Compatibles for more information on SCXI channel assignments.
Range:
.
gain is the gain setting you use for the specified channel. This gain setting applies only to the
DAQ device; if you are using SCXI, establish any gain you want on the SCXI module either
by setting jumpers on the module or by calling
DAQ device; if you are using SCXI, establish any gain you want on the SCXI module either
by setting jumpers on the module or by calling
SCXI_Set_Gain
. Refer to Appendix B,
, for valid gain settings. If you
use an invalid gain, NI-DAQ returns an error. If you call
AI_Read
for the DAQCard-500/700
or 516 and LPM devices, NI-DAQ ignores the gain.
Name
Type
Description
deviceNumber
i16
assigned by configuration utility
chan
i16
analog input channel number
gain
i16
gain setting for the channel
Name
Type
Description
reading
i16
the integer result of the A/D conversion