Guppy PRO Technical Manual
V4.1.2
138
Extended shutter
The exposure time for long-term integration of
•
up to 67 seconds for the CCD models
•
up to 22 seconds for the Guppy PRO F-503 (CMOS model)
can be extended via the advanced register: EXTENDED_SHUTTER
The longest exposure time, 3FFFFFFh, corresponds to 67.11 sec.
The lowest possible value of ExpTime is camera-specific (see
One-shot
Guppy PRO cameras can record an image by setting the one-shot bit in the
61Ch register. This bit is automatically cleared after the image is captured. If
the camera is placed in ISO_Enable mode (see
142), this flag is ignored.
If one-shot mode is combined with the external trigger, the one-shot
command is used to arm it. The following screenshot shows the sequence of
commands needed to put the camera into this mode. It enables the camera to
grab exactly one image with an external trigger edge.
Register
Name
Field
Bit
Description
0xF100020C
EXTD_SHUTTER Presence_Inq
[0]
Indicates presence of this feature (read
only)
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[1 to 5] Reserved
ExpTime
[6 to 31] Exposure time in µs
Table 67: Advanced register: Extended shutter
Note
•
Exposure times entered via the 81Ch register are
mirrored in the extended register, but not vice versa.
•
Longer integration times not only increase sensitivity, but
may also increase some unwanted effects such as noise
and pixel-to-pixel non-uniformity. Depending on the
application, these effects may limit the longest usable
integration time.
•
Changes in this register have immediate effect, even
when the camera is transmitting.
•
Extended shutter becomes inactive after writing to a
format/mode/frame rate register.
