National Instruments Welding System 321645c-01 Manual De Usuario
Chapter 2
Function Reference — WFM_Scale
NI-DAQ FRM for PC Compatibles
2-440
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National Instruments Corporation
range, NI-DAQ sets the voltage to the maximum or minimum value and returns an error.
NI-DAQ still completes the translation, however.
Range:
NI-DAQ still completes the translation, however.
Range:
Any real number that produces a voltage within the analog output range.
voltArray is the input array of double-precision values that represents the voltages NI-DAQ
is to produce at one of the outputs.
Range:
is to produce at one of the outputs.
Range:
Any real number that produces a voltage within the analog output range.
binArray is the array of binary values converted from the voltages contained in voltArray.
The values in binArray produce the original voltages when NI-DAQ writes them to a DAC
on your device. Refer to Appendix B,
The values in binArray produce the original voltages when NI-DAQ writes them to a DAC
on your device. Refer to Appendix B,
, for the calculation of binary value.
Using This Function
WFM_Scale
calculates each binary value using the following formulas:
•
Unipolar configuration:
12-bit DACs: binVal = voltage * (gain * (4,096/outputRange)).
16-bit DACs: binVal = voltage * (gain * (65,536/outputRange)).
•
Bipolar configuration:
12-bit DACs: binVal = voltage * (gain * (2,048/outputRange)).
16-bit DACs: binVal = voltage * (gain * (32,768/outputRange)).
18-bit DACs: binVal = voltage * (gain * (131,072/outputRange)).
The DSA devices use 32-bit data buffers. If you are using C or Delphi, you will need to
typecast your i32 array to i16 when you call
typecast your i32 array to i16 when you call
WFM_Scale
. If you are using Visual Basic, you
should use the
nidaqr32.bas
file (instead of
nidaq32.bas
) to relax type checking on
binArray. Each 18-bit binVal is shifted into the upper 18 bits of the array element.