Specifications

44 ST-133/ST-133A Controller Manual Version 2.H
Shutter (Normal)
Open Close Open Close Open Close
Read Read Read
Shutter (Preopen)
Open Close Open
Close
Open Close
External Sync
(negative polarity shown)
First wait
and exposure
Data
stored
Second wait
and exposure
Third wait
and exposure
Data
stored
Data
stored
t
exp
t
c
t
R
t
w1
SCAN
Figure 14. Timing diagram for the External Sync mode
External Sync with Continuous Cleans Timing
Another timing mode available with a camera is called Continuous Cleans. In addition to
the standard “cleaning” of the array, which occurs after the controller is enabled,
Continuous Cleans will remove any charge from the array until the moment the External
Sync pulse is received.
Shutter opens
Shutter remains open
for preprogrammed
exposure time
System waits while
shutter closes
Shutter opens
CCD is continuously
cleaned until External Sync
pulse is received
(shutter preopen)
(shutter normal)
CCD is continuously
cleaned until External Sync
pulse is received
Figure 15. Continuous Cleans operation flow chart
Once the External Sync pulse is received, cleaning of the array stops as soon as the
current row is shifted, and frame collection begins. With Normal Shutter operation the
shutter is opened for the set exposure time. With PreOpen Shutter operation the shutter is
open during the continuous cleaning, and once the External Sync pulse is received the
shutter remains open for the set exposure time, then closes. If the vertical rows are