Pepperl+Fuchs AL20 Mode D'emploi page 11

Elevator Light Grid AL20/AL40
Programming light switching (L), dark switching (d)
16 Programming light switching (L), dark switching (d)
Light switching means that the non-inverted outputs are active if no light beams are in-
terrupted. With dark switching, the non-inverted outputs are active in the case of an ob-
ject being detected. This function can be affected with the Reed relay.
• The magnet must be held against the Reed contact for longer than 5 sec.
• The LED display comes on and switches back and forth between the two switching ty-
pes (L) and (d) once every 5 seconds.
• When the desired switching type is displayed, remove the magnet. The last switching
type to be display will now be permanently stored and will still be displayed for about
1 to 2 seconds.
• After this procedure, the display goes off again.
Display „L"
17 Self test
The light grid attempts to detect defective beams (caused by tampering, dirt and dust or
misadjustment) and to remove them from the evaluation. A self test is thus useful to verify
how many beams are being used for evaluation.
• The magnet is held briefly (about 1 to 2 seconds) against the Reed contact. Now the
light grid is in self test mode.
• First, the switching type (L, d) that is set is displayed for 2 seconds.
• In the next step, the crossed out beams used for the evaluation are displayed with "b"
and 3 numbers in ascending order. 194 valid beams would appear as "b 1 9 4".A ma-
ximum of 194 beams are evaluated for the 40-channel light grid; for a 20-channel light
grid, the maximum number of beams is 94.
• After that, the functioning receivers (r) are also displayed with three-digit numbers. 40
functioning receivers are displayed with the sequence "r 0 4 0".
• In the next step, the functioning transmitters (t) are displayed. The sequence "t 0 4 0"
indicates that all transmitters are functioning properly for a 40-channel light grid.
• The self test is automatically followed by the sensor adjustment aid and the detection
display. This function is described in the next step.
Display „b"
Display „d"
Display „t"
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