Baumer USB3 Vision, User Manual

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18
8.3.3 Trigger Mode
Image acquisition begins after a specified external event ( trigger) occurs. Depending on
the interval of triggers used, the camera can operate either non-overlapped or overlapped
in this mode.
With regard to timings in the trigger mode, the following basic formulas need to be taken
into consideration:
Case Formula
t
exposure
< t
readout
(1) t
earliestpossibletrigger(n+1)
= t
readout(n)
- t
exposure(n+1)
(2) t
notready(n+1)
= t
exposure(n)
+ t
readout(n)
- t
exposure(n+1)
t
exposure
> t
readout
(3) t
earliestpossibletrigger(n+1)
= t
exposure(n)
(4) t
notready(n+1)
= t
exposure(n)
8.3.3.1 Overlapped Operation: t
exposure(n+2)
= t
exposure(n+1)
During overlapped operation, be mindful of the time interval during which the camera is
unable to process trigger signals (t
notready
) that occur. This interval occurs between two
exposures. When this processing time t
notready
has elapsed, the camera is able to react to
external events again.
Once t
notready
has elapsed, the timing of (E) depends on the readout time of the current
image (t
readout(n)
) and exposure time of the next image (t
exposure(n+1)
). It can be determined by
the formulas mentioned above (no. 1 or 3, dependant on the case).
In case of identical exposure times, t
notready
remains the same from acquisition to acquisi-
tion.
Exposure
Readout
t
exposure(n)
t
readout(n+1)
t
readout(n)
t
exposure(n+1)
t
triggerdelay
t
min Trigger
Flash
t
flash(n)
t
flashdelay
t
flash(n+1)
TriggerReady
t
notready
Image parameters:
Offset
Gain
Mode
Partial Scan
Timings:
A - exposure time
frame (n) effective
B - image parameters
frame (n) effective
C - exposure time
frame (n+1) effective
D - image parameters
frame (n+1) effective
E - earliest possible trigger