Allied International AVT OSCAR V2.4.0 Manual Do Utilizador

 OSCAR Technical Manual V2.4.0

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The following screenshot shows an example of broadcast commands sent with 
the Firedemo example of FirePackage (version 1V51 or newer):

•

Line 1 shows the broadcast command, which stops all cameras con-
nected to the same IEEE 1394 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.

The following chapter discusses the latency time which exists for all Oscar 
cameras when either a hardware or software 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 line time. The line 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

 Figure 53: Broadcast one-shot