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5.5
Calibrate the photocell
The photocell must be calibrated by using the following steps (see Figure 5.8)
Setting the photocell for mark and background,
A two-step setup procedure adjusts the switching threshold and the LIGHT/DARK mode.
Using the procedure below, the sensor output is set to be ON when a mark is detected.
Output ON state acquisition (MARK)
Place the target mark into the emission spot and press the MARK button until the green LED
turns OFF.
The sensor acquires the switching point for
the red and green emissions; don’t move the
mark during this phase.
Output OFF state acquisition (BKGD)
Place the background into the emission spot and press the BKGD button; the green LED
blinks once.
The sensor acquires the switching point for red and green emissions; don’t move the
background during this phase.
If the green LED lights permanently ON, a safe operation has been obtained; if it flashes at a
low rate the setup procedure has failed due to insufficient contrast; repeat the procedure
from the beginning.
Operating distance 9 mm max.
1. Ready led (green)
2. Output led (red)
3. Mark (button)
4. Background (button)
5. Lens
Figure 5.8 Photocell
