Measurement Computing Data Acquisition Systems rev.10.4 - Manual (Page 199)

Returns
DerrNoError No error
Function Usage
The term waveform/pattern output is used extensively throughout the entries for the
functions of the form daqDac…. This refers to an analog waveform output modes and/or
digital pattern output modes. These terms describe output to digital-to-analog converter
(DAC) channels and/or digital input/output (DIO) channels that are synchronously
updated by a clock source defined by the application.
The daqDacWaveGetFreq function returns the frequency via the freq parameter, The frequency is
dependent upon the clock source chosen for the selected device (see daqDacWaveSetClockSource. The
freq
parameter is a pointer to a single-precision floating point variable that must be allocated by the calling
application. The waveform/pattern output update frequency is programmed with the daqDacWaveSetFreq
function.
The returned frequency value (freq) will not be valid until the waveform is armed with the
daqDacWaveArm function.
Getting the Actual Output Update Frequency
The frequency programmed using the daqDacWaveSetFreq function may not be obtainable. The reason
for this is that either the frequency specified was outside of the operating update frequency of the output pacer
clock, or the frequency is not attainable due to the resolution of the pacer clock. If the latter is the case, then
the output pacer clock will be programmed to the nearest attainable frequency. If the frequency is outside of
the operating range of the pacer clock, then an error will be generated. See the daqDacWaveGetFreq
function for more information on the actual setting of the output pacer clock frequency.
The specifications section of the device user’s manual provides the frequency settings for the device.
Prototypes
C/C++
daqDacWaveGetFreq(DaqHandleT handle, DaqDacDeviceType deviceType, DWORD
chan, PFLOAT freq);
Visual BASIC
VBdaqDacWaveGetFreq&(ByVal handle&, ByVal deviceType&, ByVal chan&, freq!)
Program References
None
Programmer’s Manual 908494 Daq API Command Reference 4.4-17