Allied Vision Technologies AVT Marlin, Техническое руководство, Страница: 103 / 247

Description of the data path
MARLIN Technical Manual V2.4.0
103
Parameter update timing
MARLIN cameras show the following timing behavior:
• Frame rate or transfer rate is always constant (precondition:
shutter
<
transfer time)
• The delay from shutter update until the change takes place: up to 3
frames.
Figure 60: MARLIN update timing on page 103 demonstrates
this behavior. It shows that the camera receives a shutter update com-
mand while the sensor is currently integrating (Sync is low) with shutter
setting 400. The camera continues to integrate and this image is output
with the next FVal. The shutter change command becomes effective with
the next falling edge of sync and finally the image taken with shutter
200 is output with a considerable delay.
• Parameters that are sent to the camera faster than the max. frame rate
per second are stored in a FIFO and are activated in consecutive images.
Principally a Marlin camera is not able to recognize how many parameter the
user will change. Due to the fact that communication between host and cam-
era is asynchronous, it may happen that one part of parameter changes is
done in image n+1 and the other part is done in image n+2.
Figure 60: MARLIN update timing
Shutter Update Command
Current Charge Time
Sync
FVal
400 200
integrates image
with
with shutter eg 400
continues integrating
outputs image
with shutter 400
outputs image
with shutter 200
shutter 200