Supported by ...


All PixeLINK cameras.


Description


The frame interval and the required bandwidth on the communication bus are fixed by the Frame Rate value. The available frame rate range depends on the bus technology, the current video format, shutter speed, ROI and/or the video mode.  Programmers are recommended to check the ON/OFF setting and minimum and maximum value after video format, shutter speed, ROI and/or video mode have been changed.


When the Frame Rate feature is ON, the exposure time (Shutter) is limited by the frame rate value dynamically. When the Frame Rate value is changed, the minimum and maximum limits on the Shutter control will change accordingly.  The Shutter value will be forced to lie within these limits.


After a change to ROI, video format or video mode, the Frame Rate control will attempt to maintain the same frame rate.  If this is not possible, the Frame Rate control will be turned OFF.


When the Frame Rate control is OFF, the frame rate value defaults to the maximum asynchronous frame rate. The frame rate is then a function of the exposure time for exposures longer than the inverse of the frame rate value. For shorter exposure times, the frame rate will be constant. 


The absolute maximum frame rate is achieved by using asynchronous communication on the FireWire bus.  To set the maximum output frame rate, ensure the Frame Rate control is ON and set the control to its maximum value.


API Control

PxLGetFeaturePxLSetFeature


Feature ID
Number of Params
Parameters
Units
Restrictions
FEATURE_FRAME_RATE
Frame rate of the video stream
1
fValue
Frames/second
N/A


Note: To turn the frame rate control OFF, set the FEATURE_FLAGS to FEATURE_FLAG_OFF.


Note: The stream state must be off (STREAM_OFF) to modify this feature. See PxLSetStreamState.




 Feature Flags



Camera
Presence
Read Only
Auto
Manual
One-time Auto
Off
CiD
All Cameras
Yes
No
No
Yes
No
Yes
Yes


Parameters


Camera
Parameter
Unit
Type
Min
Max
Default
Step Size
Comments
All
Frame Rate
fps
Absolute
2
Varies
Max ISO
Varies
Step Size varies with the number of rows in the image. It is essentially the readout time of one row. The max frame rate is a function of the shutter speed, ROI, pixel format, trigger settings, interface bandwidth, the capabilities of the driver and the quality of the cables used. 
It will never be more than 4000 fps.