Trigger Event (TE)
The trigger event is an item specifically related to a MultiCam channel. It is abbreviated as TE. The trigger event should be considered as the instant when the channel decides to request a grabber in order to fulfill an acquisition phase.
When some specified occurrence appears, a channel trigger event is generated. The origin of the trigger event is either external or internal according to the selected triggering modality. In addition, a number of channel parameters are needed to uniquely define the source of the trigger.
As a rule, when the trigger event occurs, an acquisition phase immediately starts. However, this is not always true because some internal circumstances can prevent the trigger event to be immediately served. The rules governing the behavior during those special circumstances are referred to as "trigger event delaying mechanisms".
When the grabber triggering mode is installed, the channel is allowed to use its own grabber at any time. Consequently, there is no resynchronization delay between the TE and the event starting the acquisition phase (SAP) or the waiting phase (SWP). However, when a synchronously scanned camera is used, the acquisition phase is delayed until the start of the next camera frame.
When the timer triggering mode or system triggering mode is installed, a delay can occur between the TE and the expected SAP.
Typical trigger event situations are pictured below:
