United Electronic Industries PD2-MF, User Manual

Page: 72 / 152

Chapter 4: PowerDAQ Software (SDK)
62
Acquisition
- call the acquisition sequence using the timer or in a
program loop. Allow all points in the scan to be acquired, then calculate
how much time it takes to digitize the entire channel list. One channel
takes (1 / maximum_board_rate) (s) to be digitized. Do not forget the
“Slow bit” adds additional time and some PowerDAQ MFS models have
small additional “hold delay” time.
Get all sample already acquired
_PdAInGetSamples(…)
If software clock is selected, clock the next scan
_PdAInSwClStart(…)
Note
If you are using external pulses to clock the channel
list start, you have to address the situation when the
next scan clock comes; during your
_PdAInGetSamples(…) call. This function will return
the number of points that are stored in the buffer.
If the number of scans is equal to the board’s A/D
FIFO size, scan synchronization might be lost. You
need to be aware of these situations in your
algorithm. Using _PdAInEnableConv(…) can
enable/disable conversion “on the fly” and clear A/D
FIFO using _PdAInClearData(…).
De-Initialization
Reset the board
_PdAInReset(…)
Note
Use averaging if possible. Put several scan sequences
into the channel list and average them to reduce
noise and increase the resolution.