Rockwell Automation 5370-CVIM2 Module User Manual

Page 230

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Chapter

Chapter 6

Reference Tools

6–71

Figure 6.59 Example: “Learning” Nominal Values for Build Reference Tool

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The difference in the operation of the build reference tool when using the
absolute and delta calculation methods is illustrated as follows:

Absolute –– During each inspection cycle, the build reference tool uses the
formula to acquire the current absolute

X Center

coordinate value from the

window tool. It then subtracts the stored (“learned”) coordinate value (263
pixels in this example) from the current coordinate value and uses the
difference value to shift the gage tools as follows: A positive difference
value will shift both gage tools to the right, while a negative difference value
will shift the tools to the left.

For instance, if the object (see Figure 6.56, page 6–68) shifts right, and the
window tool returns a current

X center

coordinate value of 283, the build

reference tool will subtract 263 from 283, yielding a difference of +20. This
is the number of pixels that the gage tools will be shifted to the right.

Delta –– During each inspection cycle, the build reference tool uses the
formula to acquire the current absolute

X Center

coordinate value from the

window tool. It then subtracts from that value the constant in the formula
(263, for example) and uses the calculated difference value to shift the gage
tools as follows: A positive difference value will shift both gage tools to the
right, while a negative difference value will shift the tools to the left.

For instance, if the object (see Figure 6.56) shifts left, and the window tool
returns a current

X center

coordinate value of 243, the build reference tool

will subtract 263 (the constant) from 243, yielding a difference of –20. This
is the number of pixels that the gage tools will be shifted to the left.

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