Measurement Computing WaveBook rev.3.0 - Manual (Page 194)

C-20 daqX API - Programming Models, 6-22-99 WaveBook User’s Manual
Transfers with Driver-Allocated Buffers
This example demonstrates the use of the new
daqAdcTransferBufData()
function. The following program reads
scans of multiple channels in the background mode and uses a software
trigger to start the acquisition. Functions used include:
•
VBdaqAdcArm&(handle&)
•
VBdaqAdcSetAcq&(handle&, DaamNShot&, 0, scans&)
•
VBdaqAdcSetFreq&(handle&, freq#)
•
VBdaqAdcSetMux&(handle&, 1, channels&, DgainX1&, 1)
•
VBdaqAdcSetTrig&(handle&, DatsSoftware&, 0,0,0,0)
•
VBdaqAdcSoftTrig&(handle&)
•
VBdaqAdcTransferBufData(handle&, userBuf(0), 1,
DatmWait , retVal)
•
VBdaqAdcTransferGetStat(handle, active, retCount);
•
VBdaqAdcTransferSetBuffer(handle&, buf%(), scans&,
DatmCycleOff& + DatmUpdateSingle&)
•
VBdaqAdcTransferStart(handle&)
•
VBdaqClose(handle&)
•
VBdaqOpen("WaveBook0")
•
VBdaqSetErrorHandler(handle&, 100)
The constants used are defined as follows:
Const channels& = 8
Const scans& = 9
Const freq# = 200
As usual, the device is opened and the error handler is set up:
handle& = VBdaqOpen("WaveBook0")
ret& = VBdaqSetErrorHandler(handle&, 100)
On Error GoTo ErrorHandlerADC4
The acquisition is configured for 9 post-trigger scans and
Nshot
mode:
ret& = VBdaqAdcSetAcq&(handle&, DaamNShot&, 0,
scans&)
daqAdcSetAcq
daqAdcTransferSetBuffer
daqAdcSetMux
daqAdcTransferStart
User code
daqAdcSetTrig
daqAdcArm
daqAdcSetFreq
daqAdcSoftTrig
daqAdcTransferBufData
daqAdcTransferGetStat
Has all data
been transferred?
No
Yes
Set up the scan configuration for channels 1 to 9 with a gain of ×1:
ret& = VBdaqAdcSetMux&(handle&, 1, channels&, DgainX1&, 1)
Set the post-trigger scan rates:
ret& = VBdaqAdcSetFreq&(handle&, freq#)
Set the trigger source to a software trigger command; the other trigger parameters are not needed with a
software trigger.
ret& = VBdaqAdcSetTrig&(handle&, DatsSoftware&, 0,0,0,0)
Now to set up the buffer for a background acquisition, in update single mode with cycle mode off.
ret& = VBdaqAdcTransferSetBuffer(handle&, buf%(), scans&, DatmCycleOff& +
DatmUpdateSingle&)
Start the transfer, and trigger to begin transferring data:
ret& = VBdaqAdcTransferStart(handle&)
Arm the acquisition:
ret& = VBdaqAdcArm&(handle&)
Trigger the transfer:
ret& = VBdaqAdcSoftTrig&(handle&)
Monitor the progress of the background transfer:
VBdaqAdcTransferGetStat(handle, active, retCount);
retCount=1;
while retCount<>0 do
VBdaqAdcTransferBufData(handle&, userBuf(0), 1, DatmWait , retVal)
print"Transfer in progress: “,retCount, “scans acquired."
for i=0 to CHANS