Basic Concepts
FrontRunner™
2
v4.1.3, April 2012 Visionscape FrontRunner™ User’s Manual 2-9
I/O consists of both physical I/O and virtual I/O. Virtual I/O provides the
PC with a set of I/O points that behave much like physical I/O points, but
can only be accessed by software. They have the advantage of being
both inputs and outputs at the same time, and they can hold 32-bit values
instead of a binary state. This enables software on the PC to
communicate with the Job using a mechanism that is conceptually similar
to using physical I/O but without requiring special hardware and wiring. By
default, the system has 2048 virtual I/O points. For complete information
about the Visions System step, see Chapter 1 of the Visionscape
®
Tools
Reference.
Focus and Lighting
Now that you have control of a Smart Camera, it’s time to place a part in
front of the lens and adjust the focus using Live Video. Live Video shows
you exactly what the Smart Camera sees in real time. You want the part
to be as clear and distinct as possible. Use the Zoom buttons (just to the
right of the Live Video button) to enlarge the part as needed.
Lighting is extremely important for machine vision. If the part you want to
read is not properly illuminated, then the results will be less than optimal.
When lighting a part, consider the following:
• Surface Characteristics
• Geometry
•Size
• Region of Interest (ROI)
These considerations will determine what type of light you need to
adequately illuminate your part. For information about Optics and
Lighting, see Chapter 3 of VS-1 Smart Camera Guide.
Exposure Time
Depending on the lighting you use, you may have to adjust the exposure
time for the camera. Exposure time is the amount of time, in micro
seconds, that the camera’s CCD integrates light. Exposure time can
freeze motion when you are not using a strobe or, if you are using a
strobe, it can prevent ambient light from affecting your image. You set the
exposure time in the Exposure Time (us) property on the Acquire Step
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