Measurement Computing WaveBook rev.3.0 - Manual (Page 187)

WaveBook User’s Manual, 6-22-99 daqX API - Programming Models C-13
Complex Triggering
This example takes multiple scans from hardware using a complex analog
trigger. The acquisition will start on a rising-edge of channel 1 at 2 volts OR
a falling-edge on channel 2 at 3 volts. Functions used include:
•
VBdaqAdcSetAcq&(handle&,mode&,preTrigCount&,
postTrigCount&)
•
VBdaqAdcSetMux&(handle&, startChan&, endChan&, gain&,
flags&)
•
VBdaqAdcSetTrig&(handle&, triggerSource&, rising&,
level%, hysteresis%,channel&)
•
VBdaqAdcSetFreq&(handle&, freq!)
•
VBdaqAdcArm&(ByVal handle&, ByVal deviceType&)
•
VBdaqAdcTransferSetBuffer&(handle&, deviceType&,
chan&, buf%(), scanCount&, transferMask&)
•
VBdaqAdcTransferStart&(handle&)
•
VBdaqAdcSoftTrig&(handle&)
•
VBdaqAdcTransferGetStat(handle&, active&, retCount&)
•
VBdaqAdcClose(handle&)
The constants used in this example are defined as follows:
Const freq! = 1000
Const scans& = 9
Const channels& = 3
Const NUM_TRIG& = 2
daqAdcSetAcq
daqAdcSetMux
daqAdcSetFreq
daqAdcWaitForEvent
daqAdcTransferSetBuffer
daqAdcSetTrigEnhanced
daqAdcTransferStart
daqAdcArm
Arrays are dimensioned for configuring individual channels:
Dim chan&(NUM_TRIG&)
Dim gains&(NUM_TRIG&), polarity&(NUM_TRIG&)
Dim rising&(NUM_TRIG&)
Dim levels%(NUM_TRIG&), HYSTERESIS%(NUM_TRIG&)
Initialize these arrays which can specify individual settings for each channel:
chan&(0) = 1
gains&(0) = DgainX1&
polarity&(0) = 1
rising&(0) = DatdRisingEdge&
levels%(0) = 2
HYSTERESIS%(0) = 0.1
chan&(1) = 2
gains&(1) = DgainX1&
polarity&(1) = 1
rising&(1) = DatdFallingEdge&
levels%(1) = 3
HYSTERESIS%(1) = 0.1
Now, to open the WaveBook and specify the error handler:
handle& = VBdaqOpen("WaveBook0")
ret& = BdaqSetErrorHandler(handle&, 100)
On Error GoTo ErrorHandlerADC5
Set up the acquisition for
Nshot
, with 0 pre-trigger scans and 9 post-trigger scans.
ret& = VBdaqAdcSetAcq&(handle&, DaamNShot&, 0, scans&)
Set the scan configuration to channels 1 through 3, with a gain of ×1, and the flags parameter specifying
unipolar analog mode.
ret& = VBdaqAdcSetMux&(handle&, 1, channels&, DgainX1&,
DafAnalog&+DafUnipolar&)
Set the post-trigger scan rates:
ret& = VBdaqAdcSetFreq&(handle&, freq!)
Create the buffer to hold the collected data:
ret& = VBdaqAdcTransferSetBuffer(handle&, buf%(), scans&, DatmCycleOff& +
DatmUpdateSingle&)