Instruction manual
Guppy Technical ManualV7.4.0
162
Controlling image capture
• Line 1 shows the broadcast command, which stops all cameras connected
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.
Jitter at start of exposure
The following chapter discusses the latency time which exists for all CCD models
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 Micron/Aptina CMOS sensor of the Guppy F-036 uses a pipelined
global shutter, thus imitating the separate light sensitive and storage
area of a CCD. For more information see Chapter Pipelined global shutter
(only Guppy F-036) on page 142.
•The Micron/Aptina CMOS sensor of the Guppy F-503 uses an electronic
rolling shutter and a global reset release shutter. For more information
see Chapter Electronic rolling shutter (ERS) and global reset release shut-
ter (GRR) (only Guppy F-503) on page 143.
For the CCDs the uncertainty 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 max.
uncertainty which is equivalent to the line 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 Camera idle Camera busy
Guppy F-033 40.69 ns 32.29 μs
Guppy F-036 29.89 μs 29.89 μs
Guppy F-038 8.77 μs 68.06 μs
Guppy F-038 NIR 8.77 μs 68.06 μs
Guppy F-044 8.77 μs 66.94 μs
Table 64: Jitter at exposure start