AW00097603000 Image Acquisition Control
Basler aviator GigE 81
7.4.3 Using a Hardware Frame Start Trigger Signal
7.4.3.1 Introduction
If the Trigger Mode parameter for the frame start trigger is set to on and the Trigger Source
parameter is set to input line 1 or line 2, an externally generated electrical signal injected into the
selected source will act as the frame start trigger signal for the camera. This type of trigger signal
is generally referred to as a hardware trigger signal or as an external frame start trigger signal
(ExFSTrig).
A rising edge or a falling edge of the ExFSTrig signal can be used to trigger frame acquisition. The
Trigger Activation parameter is used to select rising edge or falling edge triggering.
Assuming that the camera is in a "waiting for frame start trigger" acquisition status, frame
acquisition will start whenever the appropriate edge transition is received by the camera.
When the camera receives a hardware 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 the camera is operating under control of an ExFSTrig signal, the period of the ExFSTrig
signal will determine the rate at which the camera is acquiring frames:
For example, if you are operating a camera with an ExFSTrig signal period of 20 ms (0.020 s):
So in this case, the frame rate is 50 fps.
For more information about
setting the camera for hardware frame start triggering and selecting an input line to receive the
ExFSTrig signal, see Section 7.4.3.4 on page 84.
the electrical requirements for the input lines, see Section 5.7 on page 38.
over triggering, see Section 7.7.3.2 on page 94.
determining the maximum allowed frame rate, see Section 7.9 on page 98.
If you are triggering frame acquisition with an ExFSTrig signal and you attempt to
acquire frames at too high a rate, some of the frame trigger signals that you apply
will be received by the camera when it is not in a "waiting for frame start trigger"
acquisition status. The camera will ignore any frame start trigger signals that it
receives when it is not "waiting for frame start trigger". (This situation is commonly
referred to as "over triggering" the camera.
To avoid over triggering, you should not attempt to acquire frames at a rate that
exceeds the maximum allowed with the current camera settings.
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