Princeton 4411-0087 Manuale Utente

ST-133 Controller Manual

Version 3.B

Shutter (Normal)

Open

Read

Shutter (Preopen)

Open

External Sync

(negative polarity shown)

First wait

and exposure

Data

stored

Second wait

and exposure

Third wait

and exposure

Data

stored

Data

stored

exp

NOTSCAN

Figure 13. Timing Diagram for the External Sync Mode

External Sync with Continuous Cleans Timing

Another timing mode available with an ST-133 controller 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 14. 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 shifted
midway when the External Sync pulse arrives, the pulse is saved until the row shifting is