Setting The Exposure Time Using "Absolute" Settings - Basler Pioneer User Manual

Image Acquisition Control
Changing the Exposure Time Base
By default, the Exposure Time Base is fixed at 20 µs, and the exposure time is normally adjusted
by setting the value of the Exposure Time Raw parameter. However, if you require an exposure time
that is longer than what you can achieve by changing the value of the Exposure Time Raw
parameter alone, the Exposure Time Base Abs parameter can be used to change the exposure time
base.
The Exposure Time Base Abs parameter value sets the exposure time base in µs. The exposure
time base can be changed in 1 µs increments and the default is 20 µs.
You can set the Exposure Time Raw and Exposure Time Base parameter values from within your
application software by using the pylon API. The following code snippet illustrates using the API to
set the parameter values:
Camera.ExposureMode.SetValue( ExposureMode_Timed );
Camera.ExposureTimeRaw.SetValue( 100 );
Camera.ExposureTimeBaseAbs.SetValue( 200 );
For detailed information about using the pylon API, refer to the Basler pylon Programmer's Guide
and API Reference.
You can also use the Basler pylon Viewer application to easily set the parameters.
For more information about the pylon Viewer, see Section 2.2 on
page 40.
10.4.2 Setting the Exposure Time Using
"Absolute" Settings
You can also set the exposure time by using an "absolute" value. This is accomplished by setting
the Exposure Time Abs parameter. The units for setting this parameter are µs and the value can be
set in increments of 1 µs.
When you use the Exposure Time Abs parameter to set the exposure time, the camera
accomplishes the setting change by automatically changing the Exposure Time Raw parameter to
achieve the value specified by your Exposure Time Abs setting. This leads to a limitation that you
must keep in mind if you use Exposure Time Abs parameter to set the exposure time. That is, you
must set the Exposure Time Abs parameter to a value that is equivalent to a setting you could
achieve by using the Exposure Time Raw parameter with the current Exposure Time Base
parameter. For example, if the time base was currently set to 62 µs, you could use the Exposure
Time Base Abs parameter to set the exposure to 62 µs, 124 µs, 186 µs, etc.
Note that if you set the Exposure Time Abs parameter to a value that you could not achieve by using
the Exposure Time Raw and Exposure Time Base parameter, the camera will automatically change
the setting for the Exposure Time Abs parameter to the nearest achieveable value.
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page 20 and Section 2.4 on
Basler pioneer