Measurement Computing ADLIB WIN - Manual (Page 69)

Chapter 20 Triggering Modes 19-1
19. TRIGGERING MODES
Triggering allows the device acquisition to begin at some external event. Typically the device is completely
initialized and started then waits for an external event to trigger the device acquisition. The Pci5500 and
Pci55xx AtoD support the collecting data before a trigger, before and after a trigger or after a trigger. The
Pci55xx DtoA option supports support collecting data after a trigger.
19.1 AL_SetTriggerMode
Prototype C\C++
ERRNUM AL_SetTriggerMode(LHLD lhld, LPSTR lpstrMode);
Visual Basic for Windows
Function AL_SetTriggerMode(ByVal lhld As Long,
ByVal lpstrMode As String) As Long
LHLD lhld handle of the LDSD
LPSTR lpstrMode address of the trigger mode string
The AL_SetTriggerMode function sets the hardware trigger operation mode of the LDSD. For the 5500
and 55xx PCI series
Parameter Description
lhld Identifies the instance of the logical device subsystem.
lpstrMode
Points to the desired trigger mode string. The available string settings are
device independent and are verified by ADLIB against the available trigger
mode options specified in the device's capabilities file.
Pci55xx Series Trigger Mode/Source Details:
MODE/SOURCE
DISABLED/DISABLED or
DISABLED/EXTERNAL – No external triggering. Acquisition starts with AL_StartDevice and
ends with AL_StopDevice.
POST_TRIG/DISABLED – INVALID setting, Post-Triggering requires an external trigger source.
POST_TRIG/EXTERNAL – Acquisition starts with the first external trigger after AL_StartDevice
and continues until completed.
PRE_TRIG/DISABLED Acquisition starts with AL_StartDevice and stops after receiving an
external trigger.
PRE_TRIG/EXTERNAL – Acquisition starts with the first external trigger after AL_StartDevice
and stops immediately after receiving the second external trigger.
ABOUT_TRIG/DISABLED – Acquisition starts with AL_StartDevice and after receiving an
external trigger, takes X more samples, then stops, where X is set with AL_SetPostSampleCount.
ABOUT_TRIG/EXTERNAL – Acquisition starts with the first external trigger after
AL_StartDevice and stops X samples after receiving the second external trigger, where X is set with
AL_SetPostSampleCount.