Global Shutter External Exposure Triggering (Non-Overlap Mode)

While waiting on the trigger event, the sensor is put into a “pre-scan read out cycle”. On detection of the trigger event, the Global Clear is pulsed to clear the charge from the sensor. The exposure period then starts and lasts for the width of the External Trigger. During the exposure period, a reference frame is read immediately as the system has no method to know how long the External Trigger will be HIGH for. When the external trigger input goes LOW, the exposure ends by transferring the charge in all pixels simultaneously to the measurement node. A signal frame read out then begins. The period of the external trigger pulse defines the overall cycle time. If the width of the trigger event is less than the frame read out time, the falling edge will be missed and a subsequent falling edge will be required to end the exposure.

Global Shutter External Exposure Triggering (Non-Overlap Mode)

Global Shutter External Exposure Triggering – Non Overlap Mode Timing Parameters

Parameter	Minimum	Maximum
Exposure (EXT Trig Pulse Width)	1 Frame + 3 Rows	30 s
Cycle Time ( EXT Trig Period)	EXT Trig Pulse Width + 1 Frame + 1 InterFrame + 6 Rows
External Start Delay	1 Row	2 Rows
EXT Trig Pulse Width	1 Frame + 4 Rows

 

Note
The table shows that the cycle time depends on the exposure selected – within the exposure range detailed in the first row the cycle time is constant, however for exposures of (2 Frames + 1 Interframe + 5 Rows) or longer the cycle time increases with exposure.