Andor Technology iXon3 Series - External (FT)

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iXon 3
Features & Functionality
3.5.1.2 - External (FT)
When the camera is idle, it is running the Idle Keep Clean Cycledescribedpreviously.OnreceiptoftheStartcommand
from the PC the camera goes into its External Keep Clean Cycle. This cycle consists of one vertical followed by one
horizontal shift, repeated continuously. The camera will repeat this cycle X times, where X is the number of image rows
onthesensor,beforeitwillacceptanyexternaltriggerevents.Oncethisperiodisoverthecamerawillcontinuerunning
the External Keep Clean cycle until an External Trigger is received. At that point the current external keep clean cycle is
completed and the camera stops all vertical clocking and waits for the programmed user delay period before starting
the read phase. During the readout phase the Image area is transferred rapidly to the Storage area. The Storage area is
then read out in the normal way.
Oncethereadoutiscompletethecameracontinuestowaitforthenextexternaltriggerevent.Whilethecamerais
waitingforthetriggereventtheshiftregisteriscontinuallyclockedbuttheImageandStorageareasarenot.Onthenext
trigger the camera again waits for the programmed delay before starting the readout phase. The camera continues in this
cycle, until the number of images requested has been captured. Because the Image area is not cleaned between trigger
events the effective exposure time is the time between events. The User Dened Delay is to allow for the capture of
events which occur after the trigger pulse. In the case of the rst trigger the effective exposure time is given by the user
dened delay since keep clean cycles have been running up until the rst trigger. This is in contrast to the subsequent
exposure periods which are dened the time between the external trigger events. Thus, for experimental protocols
that involve Continuous Wave (CW) light the rst image will be dimmer, some protocols may require that this image is
discarded.
NOTE: In the case of the 885 camera range the global clear feature will be ON until the rst trigger is received.
Figure 29: External Trigger in Frame Transfer mode