User`s manual
AW00098504000 Image Acquisition Control 
Basler ace Camera Link 83
7.3.2 Using a Software Frame Start Trigger Signal
7.3.2.1 Introduction
If the Trigger Mode parameter for the frame start trigger is set to on and the Trigger Source 
parameter is set to software, you must apply a software frame start trigger signal to the camera to 
begin each frame acquisition. Assuming that the camera is in a "waiting for frame start trigger" 
acquisition status, frame exposure will start when the software frame start trigger signal is received 
by the camera. Figure 21 illustrates frame acquisition with a software frame start trigger signal.
When the camera receives a software trigger signal and begins exposure, it will exit the "waiting for 
frame start trigger" acquisition status because at that point, it cannot react to a new frame start 
trigger signal. As soon as the camera is capable of reacting to a new frame start trigger signal, it 
will automatically return to the "waiting for frame start trigger" acquisition status.
When you are using a software trigger signal to start each frame acquisition, the camera’s Exposure 
Mode parameter must be set to timed. The exposure time for each acquired frame will be 
determined by the value of the camera’s Exposure Time Abs parameter if you are parameterizing 
the camera with Basler pylon or by the Exposure Time Raw parameter if you are parameterizing the 
camera via direct register access. 
Fig. 21: Frame Acquisition with a Software Frame Start Trigger
When you are using a software trigger signal to start each frame acquisition, the frame rate will be 
determined by how often you apply a software trigger signal to the camera, and you should not 
attempt to trigger frame acquisition at a rate that exceeds the maximum allowed with the current 
camera settings. (There is a detailed explanation about the maximum allowed frame rate at the end 
of this chapter.) Software frame start trigger signals that are applied to the camera when it is not 
ready to receive them will be ignored.
Section 7.3.2.2 includes more detailed information about applying a software frame start trigger 
signal to the camera using Basler pylon or via direct register access.
For more information about determining the maximum allowed frame rate with the current camera 
settings, see Section 7.8 on page 117.
Exposure
(duration determined by the
exposure time parameter)
Software Frame Start
Trigger Signal Received
Frame
Acquisition
Exposure
Software Frame Start
Trigger Signal Received










