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Chapter 5
Timing Modes
Introduction
Mode Shutter
Free Run Normal
External Sync Normal
External Sync PreOpen
External Sync with
Continuous Cleans
Normal
External Sync with
Continuous Cleans
PreOpen
The Princeton Instruments ST-133
Controller has been designed to allow the
greatest possible flexibility when
synchronizing data collection with an
experiment.
The chart to the right lists the timing mode
combinations. Use this chart in
combination with the detailed descriptions
in this chapter to determine the optimal
timing configuration.
Table 3. Camera Timing Modes
Fast Mode or Safe Mode
The WinView/32 Experiment Setup Timing tab page allows the user to choose Fast
Mode or Safe Mode. Figure 9 is a flow chart comparing the two modes. In Fast Mode
operation, the ST-133 runs according to the timing of the experiment, with no
interruptions from the computer. In Safe Mode operation, the computer processes each
frame as it is received. The ST-133 cannot collect the next frame until the previous frame
has been completely processed.
Fast Mode operation is primarily for collecting "real-time" sequences of experimental
data, where timing is critical and events cannot be missed. Once the ST-133 is sent the
Start Acquisition command by the computer, all frames are collected without further
intervention from the computer. The advantage of this timing mode is that timing is
controlled completely through hardware. A drawback to this mode is that the computer
will only display frames when it is not performing other tasks. Image display has a lower
priority, so the image on the screen may lag several images behind. A second drawback is
that a data overrun may occur if the number of images collected exceeds the amount of
allocated RAM or if the computer cannot keep up with the data rate.
Safe Mode operation is primarily useful for experiment setup, including alignment and
focusing, when it is necessary to have the most current image displayed on the screen. It
is also useful when data collection must be coordinated with external devices such as
external shutters and filter wheels. As seen in , in Safe Mode operation, the computer
controls when each frame is taken. After each frame is received, the camera sends the
Stop Acquisition command to the camera, instructing it to stop acquisition. Once that