User`s manual
AW00098504000 Image Acquisition Control 
Basler ace Camera Link 101
7.6.2 Trigger Wait Signals
If a camera receives a hardware acquisition start trigger signal when it is not in a "waiting for 
acquisition start trigger" acquisition status, it will simply ignore the trigger signal and will generate 
an overtrigger error. 
If a camera receives a hardware frame start trigger signal when it is not in a "waiting for frame start 
trigger" acquisition status, it will simply ignore the trigger signal and will generate anovertrigger 
error.
The camera’s acquisition trigger wait signal gives you the ability to check whether the camera is in 
a "waiting for acquisition start trigger" acquisition status. If you check the acquisition trigger wait 
signal before you apply each hardware acquisition start trigger signal, you can avoid applying 
acquisition start trigger signals to the camera that will be ignored.
The camera’s frame trigger wait signal gives you the ability to check whether the camera is in a 
"waiting for frame start trigger" acquisition status. If you check the frame trigger wait signal before 
you apply each hardware frame start trigger signal, you can avoid applying frame start trigger 
signals to the camera that will be ignored.
These signals are designed to be used when you are triggering acquisition start or frame start via 
a hardware trigger signal.
For more information about the overtrigger error, see Section 10.10.2 on page 209.
7.6.2.1 Acquisition Trigger Wait Signal
As you are acquiring frames, the camera automatically monitors the acquisition start trigger status 
and supplies a signal that indicates the current status. The Acquisition Trigger Wait signal will go 
high whenever the camera enters a "waiting for acquisition start trigger" status. The signal will go 
low when an external acquisition start trigger (ExASTrig) signal is applied to the camera and the 
camera exits the "waiting for acquisition start trigger status". The signal will go high again when the 
camera again enters a "waiting for acquisition trigger" status and it is safe to apply the next 
acquisition start trigger signal. 
If you base your use of the ExASTrig signal on the state of the acquisition trigger wait signal, you 
can avoid "acquisition start overtriggering", i.e., applying an acquisition start trigger signal to the 
camera when it is not in a "waiting for acquisition start trigger" acquisition status. If you do apply an 
acquisition start trigger signal to the camera when it is not ready to receive the signal, it will be 
ignored and an overtrigger error will be reported. 
Figure 28 illustrates the Acquisition Trigger Wait signal with the Acquisition Frame Count parameter 
set to 3 and with exposure and readout overlapped. The figure assumes that the trigger mode for 
the frame start trigger is set to off, so the camera is internally generating frame start trigger signals.










