Specifications

405-00022-00VA6x User’s Reference
30 Rev 00; 16 October 2007
View Time = 1/(640*5) = 315 microseconds
This is within the camera exposure range (and shutter speeds) but will require good illumination,
perhaps by an LED strobe, because the exposure time is brief.
In iNspect/iLabel, you adjust the camera’s exposure time using the Exposure Control slider on
the Vision Appliance’s Sensor Setup screen. In Sherlock you adjust the exposure time by pro-
gramming the shutter speed, using the IO:Camera:Set Shutter instruction, or using CamExpert to
create a camera file. The maximum shutter time (exposure time) must be less than the frame time.
As the frame rate increases, the maximum shutter time decreases.
In practice, you will adjust the exposure to balance good image contrast against visible blur due
to part motion.
Blurring of the image caused by the motion of the part (motion blur), even when not visible to the
human eye looking at the camera image, will reduce the accuracy of measurements. Ideally, mea-
surements should be performed on a part that is not moving, so there is no motion blur and so that
a longer exposure (and smaller lens aperture) can be used.
Progressive Scan Cameras
In addition to programmable exposure, the camera is non-interlaced (usually called progressive
scan). If you intend to use a different camera with your Vision Appliance, call ipd for supported
cameras. Make sure that it is progressive scan, has an electronic shutter, and is compatible with
the control signals, power, and cabling.
Strobe Lighting
A strobe light provides a brief, high-intensity pulse of light that can help reduce motion blur and
still provide adequate illumination to the part being inspected. Traditional xenon strobe lights are
bright and can be very short in duration, less than 100 microseconds, to “freeze” the part motion.
Xenon strobes have substantial variability in intensity. This can create variations in the image
quality, which could be mistaken for variation in the part quality. Xenon strobe lights are used
only when there is no easier way to get short, high-intensity light. LEDs (Light Emitting Diodes)
can also be used as a strobe, and over-driven to give a short, bright pulse of light.
Even with a strobe illumination source, you need a camera with an electronic shutter and expo-
sure time to prevent ambient light from contaminating the image. The Vision Appliance has a
dedicated I/O line for firing a fast strobe, because this must be done at a certain time after the
exposure has been triggered. Longer duration light, for example LEDs again, can be controlled