Measurement Computing Data Acquisition Systems rev.10.4 - Manual (Page 155)

daqCvtLinearConvert
Also See: daqCvtLinearSetup,
daqCvtLinearSetupConvert, daqCvtSetAdcRange
Format
daqCvtLinearConvert(counts, scans, fValues, nValues)
Purpose
daqCvtLinearConvert converts the ADC readings into floating point numbers using the linear
relationship that was specified with daqCvtLinearSetup.
Parameter Summary
Parameter Type Description
counts PWORD Acquired ADC readings to be converted
scans DWORD Number of scans to be converted
fValues PFLOAT Array to hold the converted readings
nValues DWORD Size of the reading array
Parameter Values
counts: valid pointer to an array of integer words (2 bytes) which contain the data to perform the linear
conversion
scans: the number of scans to be converted, from 1 to the size of the counts array (in scans)
fValues: valid pointer to an array of single precision floating point (4 bytes) values which will store the
converted readings upon return of this command
nValues: the size of the fValues arrary should be at least equal to:
[scans * (channels in scan) * (the sample size, normally 2 bytes)]
Returns
DerrNoError No error
Function Usage
For all functions of the form daqCvt..., raw data to be converted must be unsigned
(i.e., the dafUnsigned value must be set using the daqAdcSetScan function).
For T/C and RTD conversion, users of Daq/2000 Series devices* and/or Daq PC Cards must
be sure that the main unit is using ten volt range gains settings, either unipolar (0 V to 10 V)
or bipolar (-5 V to +5 V).
See the “T/C Gains Settings” section in the daqCvtTCConvert function entry for the
appropriate settings.
* Daq/2000 Series devices include DaqBook/2000 Series, DaqScan/2000 Series, DaqLab/2000
Series, and DaqBoard/2000 Series devices.
The daqCvtLinearConvert function may be invoked repeatedly to perform multiple conversions, each
using the same linear relationship. For convenience, daqCvtLinearSetupConvert can perform both
setup and conversion.
Programmer’s Manual 908494 Daq API Command Reference 4.3-29