Measurement Computing Data Acquisition Systems rev.10.4 - Manual (Page 219)

Parameter Type Definitions
deviceType–(DaqDacDeviceType)
Definition chan Value Description
0 Start the transfer of waveform/pattern output data where DAC0 is one of the
channels being output.
1 Start the transfer of waveform/pattern output data where DAC1 is one of the
channels being output.
2 Start the transfer of waveform/pattern output data where DAC2 is one of the
channels being output.
DddtLocal
3 Start the transfer of waveform/pattern output data where DAC3 is one of the
channels being output.
WaveType-(DaqDacWaveType)
Definition Description
DdwtSine Output a sine wave
DdwtSquare Output a square wave
DdwtTriangle Output a triangle wave
Returns
DerrInvDacChan The DAC channel number doesn’t exist
DerrInvDacParam Parameters were out-of-range
DerrInvPredefWave Predefined waveform is not supported
DerrMemAlloc Not enough memory was available to build the waveform
DerrNotCapable Hardware is not capable of this function
DerrNoError No error
For more details on error messages refer to the Daq Error Table.
Function Usage
The daqDacWaveSetPredefWave function creates the defined waveform on the specified channel buffer
as soon as the acquisition is armed—however, this function should only be used in static output mode.
DaqBoard (ISA-Type), DaqBook/2000 Series, DaqBoard/2000 Series, and cPCI
DaqBoard/2000c Series
When using the daqDacWaveSetPredefWave function with the DaqBoard(ISA) devices, it is important to
note that they use 12-bit DAC’s. However, for consistancy, all functions use 16-bit values. The driver will
convert 16-bit parameters to appropriate 12-bit values for the DaqBoard (ISA), while the 16-bit value is passed
directly to 1000 Series and 2000 Series devices.
Thus, an amplitude or offset value of 0 corresponds to the minimum output of the DAC, as follows:
•
-10V for DaqBoard/2000 Series
•
0V for DaqBoard (ISA-type)
A value of 65,535 corresponds to the maximum output of the DAC, as follows:
•
10V for DaqBoard/2000 Series
•
5V for DaqBoard (ISA-type)
The specifications section of the device user’s manual provides the resolution values for the device; for
example: the voltage for a DaqBoard/2000 Series devices has a resolution of approximately 0.305 mV
(20 V / 65,535).
Programmer’s Manual 908494 Daq API Command Reference 4.4-37