
OPERATION
Light Curtain Operation
The 618 light curtain uses 18 transmit diodes
in the TX detector and 18 receive diodes in
the RX detector. The light curtain uses an 81
beam pattern when the doors are fully open
(Fig 1). The pattern changes to 50 beams as
the doors close to approximately 650mm, and
maintains 18 beams right up to closure.
Surface mount technology has led to a great
improvement in the optics allowing diagonal
beams to function to almost door closure. The
diodes are manufactured using a technique
which improves both consistency and reliability.
The special lenses, unique to Memco, used in
conjunction with the surface mount diodes
optimise the system performance.
Trouble-Shooting LEDS
There are two red trouble-shooting LEDS
positioned 25cm and 31cm from the top of
the TX detector. The states they can indicate
are shown in Table 1.
Power Reduction Function
This software feature prolongs the life-span
of the detectors by putting them into a less
active state when the lift is not in use. It
automatically activates when the detectors
are stopped and close together for more than
10 seconds. In this mode scanning is reduced
to once every 2 seconds. If the doors start to
open, or an obstruction is detected then the
normal scanning and trigger mode is
resumed.
Timeout Function
This software feature allows up to 3 non-
adjacent light-curtain TX diodes to be ignored
if they are permanently obstructed. It is
automatically activated 10 seconds after a
beam is permanently blocked. This is a useful
service feature which enables detectors
defaced by vandalism to continue working
while arrangements are made to replace them.
System Connection
For trouble-free installation we recommend
installing the 618 system with a Memco 280
or 281 power supply. However in many
situations the 618 can be directly connected
to the lift controller or door operator.
The power supply is available in two versions;
the Model 280 is powered from an AC supply
(115 / 230V) while the Model 281 is powered
from a DC supply (15 - 36V).
Fig 2: 618 profile
Table 1: Trouble Shooting Guide
LED Status Possible Cause
OFF
OFF No Power
FLASHING
OFF TX/RX connection open circuit
ON Triggered state obstruction
OFF between detectors
ON Normal scanning state
ON
ON A diode has been timed out
FLASHING SLOWLY
37.3
9.0
24.0