Cheetah KAC Camera User Manual | Camera Link (CLF) Interface
October 1, 2019
Page
96
of
135
Rev 7.2
5.7.3 Variable Frame Time – Programmable Line
and Frame Time
Variable frame time control provides the ability to run the camera in full resolution and a
frame rate slower than the nominal frame readout rate. The camera can provide very high
data rates that can quickly over-run the bandwidth of the frame grabber and output
interface. By adding a delay after the readout of each line (each line = two rows of the
image sensor) and at the end of the frame, the overall output frame rate can be reduced
matching the camera frame rate to each application-specific requirement. Use the
programmable line time to add delay at the end of each line readout to match the camera
data output rate so the frame grabber does not experience over-runs. Use the
programmable frame period to add additional line delays at the end of the frame to
achieve the desired frame time. The line time control should only add enough delay to the
camera line time to match the frame grabber data capture rate. Adding additional line
delay will decrease overall camera performance by increasing dark current within the
image.
If the frame time is greater than 50ms, keep the camera still to prevent motion smear
from appearing on the image.
5.8 Camera Triggering
5.8.1 Triggering Inputs
In the normal mode of operation, the camera is free running. Using the trigger mode
allows the camera to be synchronized to an external timing pulse. Trigger inputs can be
used to control the exposure times of Frame A and Frame B or can be used to control Dual
Video mode switching. In Dual Video mode, enabling the trigger input causes the camera
to output a user defined number of Frame As followed by a user defined number of
Frame Bs upon receipt of Trigger. In Dual Video Trigger mode, the camera outputs Frame
As until trigger is received and then outputs a user defined number of Frame Bs.
There are three input modes available for external triggering – computer (CC), internal
(pulse generator), and external. Please note that the desired trigger input has to be
mapped to corresponding camera input. Refer to the I/O Control section for more
information.
•
“
External
” – the camera receives the trigger signal coming from the connector
located on the back of the camera.
•
“
Computer
” – the camera receives the trigger signal command from the CC
signals.
•
“
Internal
” – the camera has a built-in programmable pulse generator – refer to
“Pulse Generator” section. In Internal triggering mode, the camera receives the
trigger signal from the internal pulse generator.
