Private Sub vbMain()
Const MAX_COUNT = 128
Dim stat
Dim dfltRM
Dim sesnIN
Dim sesnOUT
Dim aKey
Dim buf
Dim etype
Dim event
Dim retCount | As ViStatus
As ViSession
As ViSession
As ViSession
As String * VI_FIND_BUFLEN
As String * MAX_COUNT
As ViEventType
As ViEvent
As Long | 'For checking errors
'Communication channels
'Communication channels
'Communication channels
'Access key for lock
'To store device data
'To identify event
'To hold event info
'To hold byte count |
Rem Begin by initializing the system
stat = viOpenDefaultRM(dfltRM)
If (stat < VI_SUCCESS) Then
Rem Error initializing VISA...exiting
Exit Sub
End If
Rem Open communications with VXI Device at Logical Addr 16
stat = viOpen(dfltRM, "VXI0::16::INSTR", VI_NULL, VI_NULL, sesnIN)
stat = viOpen(dfltRM, "VXI0::16::INSTR", VI_NULL, VI_NULL, sesnOUT)
Rem We open two sessions to the same device
Rem One session is used to assert triggers on TTL channel 4
Rem The second is used to receive triggers on TTL channel 5
Rem Lock first session as shared, have VISA generate the key
Rem Then lock the second session with the same access key
stat = viLock(sesnIN, VI_SHARED_LOCK, 5000, "", aKey)
stat = viLock(sesnOUT, VI_SHARED_LOCK, VI_TMO_IMMEDIATE, aKey, aKey)
Rem Set trigger channel for sessions
stat = viSetAttribute(sesnIN, VI_ATTR_TRIG_ID, VI_TRIG_TTL5)
stat = viSetAttribute(sesnOUT, VI_ATTR_TRIG_ID, VI_TRIG_TTL4)
Rem Enable input session for trigger events
stat = viEnableEvent(sesnIN, VI_EVENT_TRIG, VI_QUEUE, VI_NULL)
Rem Assert trigger to tell device to start sampling
stat = viAssertTrigger(sesnOUT, VI_TRIG_PROT_DEFAULT)
Rem Device will respond with a trigger when data is ready
stat = viWaitOnEvent(sesnIN, VI_EVENT_TRIG, 20000, etype, event)
If (stat < VI_SUCCESS) Then
stat = viClose (dfltRM)
Exit Sub
End If
Rem Close the event
stat = viClose(event)
Rem Read data from the device
stat = viRead(sesnIN, buf, MAX_COUNT, retCount)
Rem Your code should process the data
Rem Unlock the sessions
stat = viUnlock(sesnIN)
stat = viUnlock(sesnOUT)
Rem Close down the system
stat = viClose(sesnIN)
stat = viClose(sesnOUT)
stat = viClose(dfltRM)
End Sub |
