Measurement Computing WaveBook rev.3.0 - Manual (Page 216)

D-20 daqX API - Command Reference, 6-24-99 WaveBook User’s Manual
daqCalSetConstants
DLL Function daqCalSetConstants(DaqHandleT handle, DWORD channel, DaqAdcGain gain, DaqAdcRangeT
range, WORD gainConstant, SHORT offsetConstant );
C daqCalSetConstants(DaqHandleT handle, DWORD channel, DaqAdcGain gain, DaqAdcRangeT
range, WORD gainConstant, SHORT offsetConstant );
Visual BASIC VBdaqCalSetConstants(ByVal handle&, ByVal channel&, ByVal gain&, ByVal range&, ByVal
gainConstant%, ByVal offsetConstant% );
Delphi daqCalSetConstants(handle: DaqHandleT;channel:DWORD; gain: DaqAdcGain; range:
DaqAdcRangeT; gainConstant:WORD; offsetConstant:SHORT );
handle Handle to the device for which ADC transfer status is to be retrieved
channel Channel number to apply the calibration settings
gain Gain range to apply the calibration settings
range A/D input range to apply the calibration settings
gain Gain value to apply
Parameters
offset Offset value to apply
Returns DerrNoError No error (see the API Error Codes table at the end of this chapter).
See Also daqCalGetConstants,daqCalSelectCalTable,daqCalSelectInputSignal,daqCalSaveConstants
Program References None
Used With WaveBook/512, WaveBook/516 series
Description
daqCalSetConstants
sets the user-accessible calibration constants. These calibration constants are gains and offsets that are applied
to the input data. The data comes in, is multiplied by the gain, then the offset is added to it. The resulting data is the conversion between
the raw A/D data and the data that is presented during the acquisition. Each channel, gain, and bipolar/unipolar setting has a different pair
of gain and offset values. The first three parameters of the daqCalSetConstants function specify which set of constants are to be
changed. The last two parameters are the actual constants. These constants are in a particular binary format. The gain constant is
32768 times the gain. For a gain of ×1, the gain constant is 32768 or 0x8000. The maximum gain is approximately ×2 (65535/32768),
and the minimum gain is ×0 (0/32768). The offset (a left-justified signed 12-bit number) is added to the final result. A single least-
significant bit has an integer value of 16 or 0x0010. Setting the calibration constants affects subsequent acquisitions until another
daqOpen
is performed. After daqOpen, the original calibration constants are re-read from the NVRAM in the WaveBook and expansion
chassis; then, the working copy as set by daqCalSetCalConstants is overwritten.
daqClose
DLL Function daqClose(DaqHandleT handle);
C daqClose(DaqHandleT handle);
Visual BASIC VBdaqClose&(ByVal handle&)
Delphi daqClose(handle:DaqHandleT)
Parameters handle Handle to the device to be closed
Returns DerrNoError No error (see the API Error Codes table at the end of this chapter).
See Also daqOpen
Program References ADCEX1.C, DACEX1.C, DIGEX1.C, DYN32ENH.C, DAQEX.FRM (VB), ADCEX.PAS, ERREX.PAS (Delphi)
Used With All devices
Description
daqClose
is used to close a Daq* device. Once the specified device has been closed, no subsequent communication with the device can
be performed. In order to re-establish communications with a closed device, the device must be re-opened with the daqOpen function.