Basler ace acA1920-155, User Manual, Page: 177 / 326

AW00123404000 Image Acquisition Control
Basler ace USB 3.0 167
6.10.2 Increasing the Maximum Allowed Frame Rate
You may find that you would like to acquire frames at a rate higher than the maximum allowed with
the camera’s current settings. In this case, you must adjust one or more of the factors that can
influence the maximum allowed rate and then check to see if the maximum allowed rate has
increased:

Decreasing the height of the Image ROI can have a significant impact on the maximum
allowed frame rate. If possible in your application, decrease the height of the Image ROI.

If you are using normal exposure times and you are using the camera at it’s maximum
resolution, your exposure time will not normally restrict the frame rate. However, if you are
using long exposure times or small areas of interest, it is possible that your exposure time is
limiting the maximum allowed frame rate. If you are using a long exposure time or a small ROI,
try using a shorter exposure time and see if the maximum allowed frame rate increases. (You
may need to compensate for a lower exposure time by using a brighter light source or
increasing the opening of your lens aperture.)

The frame transmission time will not normally restrict the frame rate. But if you are using
multiple cameras connected to one hub, you may find that the transmission time is restricting
the maximum allowed rate. In this case, you could use a multiport host adapter in the PC
instead of a hub.
If you are working with an acA1920-25, acA2500-14 , acA3800-14 or acA4600-10 camera:
Use the ERS mode rather than the global reset release shutter mode. The ERS mode allows
overlapping frame acquisition while the global reset release mode does not. Overlapping frame
acquisitions is, however, necessary for achieving the highest frame rates.
For more information about Image ROI settings, see Section 8.5 on page 207 .
For more information about the ERS mode, see Section 6.6.2 on page 132 .
An important thing to keep in mind is a common mistake new camera users
frequently make when they are working with exposure time. They will often use a
very long exposure time without realizing that this can severely limit the camera’s
maximum allowed frame rate. As an example, assume that your camera is set to
use a 1/2 second exposure time. In this case, because each frame acquisition will
take at least 1/2 second to be completed, the camera will only be able to acquire
a maximum of two frames per second. Even if the camera’s nominal maximum
frame rate is, for example, 100 frames per second, it will only be able to acquire
two frames per second because the exposure time is set much higher than
normal.