Guppy PRO Technical Manual
V4.1.2
143
•
Line 1 shows the broadcast command, which stops all cameras connected
to the same IEEE1394 bus. It is generated by holding the Shift key down
while clicking on Write.
•
Line 2 generates a broadcast one_shot in the same way, which forces all
connected cameras to simultaneously grab one image.
Jitter at start of exposure
The following chapter discusses the latency time which exists for all Guppy PRO
CCD models when a hardware trigger is generated, until the actual image
exposure starts.
Owing to the well-known fact that an Interline Transfer CCD sensor has both a
light sensitive area and a separate storage area, it is common to interleave
image exposure of a new frame and output that of the previous one. It makes
continuous image flow possible, even with an external trigger. The uncertain
time delay before the start of exposure depends on the state of the sensor. A
distinction is made as follows:
FVal is active
the sensor is reading out, the camera is busy
In this case the camera must not change horizontal timing so that the trigger
event is synchronized with the current horizontal clock. This introduces a
maximum uncertainty which is equivalent to the row time. The row time
depends on the sensor used and, therefore, can vary from model to model.
FVal is inactive
the sensor is ready, the camera is idle
In this case the camera can resynchronize the horizontal clock to the new
trigger event, leaving only a very short uncertainty time of the master clock
period.
Model
Exposure start jitter (while FVal)
Exposure start jitter (while camera idle)
Guppy PRO F-031
14.2 µs
2.9 µs
Guppy PRO F-032
24.3 µs
3.0 µs
Guppy PRO F-033
23.4 µs
2.6 µs
Guppy PRO F-046
27.4 µs
2.6 µs
Guppy PRO F-125
33.2 µs
5.0 µs
Guppy PRO F-146
56.0 µs
13.7 µs
Guppy PRO F-201
29.5 µs
10.3 µs
Guppy PRO F-503
not applicable
not applicable
Table 70: Jitter at exposure start (no binning, no sub-sampling)
