Delta CS64A - Manual (Page 12)

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5. Sample Quick Test
You can do a quick test using the CS64A simply by wiring the +24V power, placing the
samples one at a time at the standoff distance (1.75 to 2 inches from the bottom of the
CS64A-00), recording the analog readings, and calculating the ratios on a calculator:
Measure Calculate
Sample NIR Red Green Blue Red/NIR Grn/NIR Blu/NIR
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Differences in the Red/NIR, Green/NIR and Blue/NIR ratios are used to
differentiate between colors.
Usually, the amplitudes cannot be used directly since they vary with distance, dirt, etc.
Occasionally, it is necessary to use the NIR amplitude to differentiate between shades of
the same color (light and dark gray, for example). If the NIR amplitude is used, be sure
that:
1. The sensor to target distance is tightly controlled,
2. The sensor window is kept clean and/or
3. There is sufficient variation in the NIR amplitude—10% is usually adequate for very
clean and controlled conditions, while more difference will allow for more distance
variation.