Princeton Digital (USA) 4411-0062 User Manual
52 I-PentaMAX System Manual
Version 3.A
Full Speed (sync) or Safe Mode (async)
Selection of Full Speed (formerly known as Synchronous mode) or Safe Mode (formerly
known as Asynchronous mode) determines the overall control of experiment timing. In
Full Speed mode, the I-PentaMAX runs according to the timing of the experiment, with
no interruptions from the computer. In Safe Mode, the computer processes each frame as
it is received and the I-PentaMAX cannot collect the next frame until the previous frame
has been completely processed. Flow charts for both modes of operation are shown in
Figure 14 on the next page.
known as Asynchronous mode) determines the overall control of experiment timing. In
Full Speed mode, the I-PentaMAX runs according to the timing of the experiment, with
no interruptions from the computer. In Safe Mode, the computer processes each frame as
it is received and the I-PentaMAX cannot collect the next frame until the previous frame
has been completely processed. Flow charts for both modes of operation are shown in
Figure 14 on the next page.
Full Speed mode is primarily for collection of back-to-back experimental data, where
timing is critical and events cannot be missed. Once the I-PentaMAX is sent the Start
Acquisition command (STARTACQ) from 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 video monitor
connected to the VIDEO output will always display the current image. 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.
timing is critical and events cannot be missed. Once the I-PentaMAX is sent the Start
Acquisition command (STARTACQ) from 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 video monitor
connected to the VIDEO output will always display the current image. 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 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, or when data collection is part of a macro. As seen in Figure 14, in the
Safe Mode the computer controls when each frame is taken. After each frame is received,
the camera sends the Stop Acquisition command (STOPACQ) to the camera, instructing it
to stop acquisition. Once that frame is completely processed and displayed, a STARTACQ
is sent from the computer to the camera, allowing it to take the next frame. Display is
therefore, at most, only one frame behind the actual data collection.
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, or when data collection is part of a macro. As seen in Figure 14, in the
Safe Mode the computer controls when each frame is taken. After each frame is received,
the camera sends the Stop Acquisition command (STOPACQ) to the camera, instructing it
to stop acquisition. Once that frame is completely processed and displayed, a STARTACQ
is sent from the computer to the camera, allowing it to take the next frame. Display is
therefore, at most, only one frame behind the actual data collection.
One disadvantage of the Safe Mode is that events may be missed during the experiment,
since the I-PentaMAX is disabled for a short time after each frame. The time delay
between each frame acquisition is no longer fixed since the software, which has
significantly more jitter than the hardware, has full control of data collection.
since the I-PentaMAX is disabled for a short time after each frame. The time delay
between each frame acquisition is no longer fixed since the software, which has
significantly more jitter than the hardware, has full control of data collection.
Standard Timing Modes
The basic I-PentaMAX timing modes are Freerun, External Sync, and Software Trigger.
These timing modes are combined with the Shutter options to provide the widest variety
of timing modes for precision experiment synchronization.
These timing modes are combined with the Shutter options to provide the widest variety
of timing modes for precision experiment synchronization.
The shutter options available include Normal, Preopen, Disable Opened or Disable
Closed. Disable simply means that the shutter will not operate during the experiment.
Disable closed is useful for making dark charge measurements, or when no shutter is
present in the system. Preopen, available in the External Sync mode, opens the shutter as
soon as the I-PentaMAX is ready to receive an External Sync pulse. This is required if the
Closed. Disable simply means that the shutter will not operate during the experiment.
Disable closed is useful for making dark charge measurements, or when no shutter is
present in the system. Preopen, available in the External Sync mode, opens the shutter as
soon as the I-PentaMAX is ready to receive an External Sync pulse. This is required if the