National Instruments NI 1712 User Manual - page 55
6-6
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Chapter 6
Image Acquisition
Determining the Scan Mode
The
maximum frame rate for selected scan mode
is determined by the partial scan mode and
binning mode. Because the amount of data read out of the sensor is less in 1/2 or 1/4 scan mode,
the readout takes less time, and you can achieve faster frame rates. The same is true of binning.
When binning is enabled, the readout takes less time, and you can achieve faster frame rates.
Refer to the
Partial Scan Mode
and
Binning
sections of Chapter 5,
Image Acquisition
, for more
information about partial scanning and binning.
Use the maximum frame rate specifications for your smart camera in your scan mode in
Appendix A,
Specifications
, to determine the
maximum frame rate for selected scan mode
.
Determining the Exposure Time
The minimum frame period depends on exposure time, lighting mode, and trigger delay.
A longer exposure time results in a longer frame period, and a slower maximum frame rate.
Determining the Trigger Delay
If the trigger delay is set longer than the untriggered minimum frame period, the trigger delay
value further limits the
min frame period
. When the trigger delay is specified in milliseconds,
the software includes this in the calculation of the maximum frame rate indicator.
Calculating the Minimum Frame Period
Refer to Equations 6-3 and 6-4 to calculate the minimum frame period for untriggered
acquisitions with and without strobing.
(6-3)
(6-4)
Refer to Equations 6-5 and 6-6 to calculate the minimum frame period for triggered acquisitions
with and without strobing.
(6-5)
(6-6)
where
T
is the trigger synchronization variability,
L
is the lighting turn-on time,
E
is the exposure time, and
R
is the image readout duration.
min frame period
NoStrobeNoTrigger
T L E
+
+
=
min frame period
WithStrobeNoTrigger
T L E R
+
+
+
=
min frame period
NoStrobeWithTrigger
max T L E
+
+
Trigger Delay
,
(
)
=
min frame period
WithStrobeWithTrigger
max T L E R
+
+
+
Trigger Delay
,
(
)
=