User manual

Chapter 3 Software Overview
NI-DAQ User Manual for PC Compatibles 3-18 ni.com
detrimental to your applications. Use
AI_VScale
to convert the binary
values to voltages at a later time if you want. See Figure 3-1 for the function
flow typical of single-point data acquisition. Also, refer to the NI-DAQ
Examples Online Help file (
nidaqex.hlp
) to find a related example.
When using SCXI as a front end for analog input to the DAQCard-700,
analog input Lab and 1200 devices, MIO and AI device, or LPM devices,
it is not advisable to use the
AI_VRead
function because that function does
not take into account the gain of the SCXI module when scaling the data.
Use the
AI_Read
function to obtain the unscaled data, then call the
SCXI_Scale
function using both the SCXI module gain and the DAQ
device gain.
Figure 3-1. Single-Point Analog Reading with Onboard Conversion Timing
No
Ye s
Ye s
No
Another reading?
AI_VRead
AI_Read
Binary reading?
AI_Mux_Config
AI_Configure
Retrieve an analog
reading in terms of a
binary value.
Retrieve an analog
reading in terms of
voltage.
Add AMUX-64T
configuration.
Change analog input
default configuration.