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External synchronization
In this mode, the acquisition frame rate is configured using an external signal, typically FPS_Tint_in
signal on the synchro connector available on all C-RED 3 models.
Alternatively, on C-RED 3 CL model, the acquisition can also be controlled using one of the camera link
control signals available on the camera link connector #1 (requires Firmware 1.1.0 or above).
The selection between the different external source is done using one of the following commands:
“
set extsynchro source external
”: selects FPS_Tint_in signal on Lemo® connector as input
signal
“
set extsynchro source cc1
”: selects Camera Link/CC1 as input signal
“
set extsynchro source cc2
”: selects Camera Link/CC2 as input signal
“
set extsynchro source cc3
”: selects Camera Link/CC3 as input signal
“
set extsynchro source cc4
”: selects Camera Link/CC4 as input signal
The integration duration can either be controlled using the same signal (external) or configured by
software (internal).
Note 1: The external signals are sampled at the camera master clock rate(cmcr). So, there is a jitter of
1/18214000s (~=55ns) on the readout of these signals. It means start of acquisition has a jitter of
1/18214000 s. If the integration duration is also managed by the external signal, there is an additional
1/18214000s jitter on the end of integration.
Note 2: When the external synchronization is used, the camera is fully slave on the external FpsTint_in
signal. It means non periodic trigger input can be used.
The selection between external or internal configuration of the integration duration is done using “
set
extsynchro exposure external
” and “
set extsynchro exposure internal
” commands.
The polarity of the control signal can be inverted if required.
The inversion of the signal is enabled or disabled using “
set extsynchro polarity inverted
”
or “
set extsynchro polarity standard
” commands.
It is also possible to configure an extra delay when processing synchronization signal, allowing to
synchronize different devices with the same signal. The granularity of this extra delay is the camera
master clock rate (18214 kHz).
The synchronization extra delay can be set using the “
set
syncdelay
” command. Current extra delay
value can be read using “
syncdelay
” command. Setting extra delay value to 0 disables the generation
of an extra delay during external synchro signal processing, requesting the camera to process the
synchro signal as fast as possible.
“minsyncdelay”
and
“maxsyncdelay”
commands allow to retrieve the valid range of extra
synchronization delay parameter.
