Using a Memco 280/281 Power Supply
The Memco power supply provides:-
· a regulated DC supply for the 618
detectors.
· a relay output for connection to the car
door re-open circuit.
This eliminates concern about the electrical
environment into which the 618 is being
installed and makes wiring straightforward
(Fig 3).
The power supply also has a beeper which
sounds when an object is detected. A switch
is provided to disable this beeper. The unit is
factory-set for “failsafe” operation using
standard 618 (PNP-N/C) detectors, but
switches allows detectors with other
transistor configurations to be used.
Direct Connection
The 618 can be connected directly to the lift-
controller or door-operator if it has asuitable
power supply and “door reopen” circuit (Fig
4). The power supply must be regulated DC
(11-30V) with no transients. The door re-
open circuit must accept a transistor drive
and guarantee the signal current will never
exceed 100mA.
The standard 618 transistor configuration is
PNP Normally-Closed (PNP-N/C). A PNP
transistor means the load will be connected
between the output and 0V (i.e. when the
transistor is turned on the load will draw current
from the transistor output). Normally Closed
means the transistor is turned on when a
person or object is not being detected. Other
transistor configurations are available on
request but PNP Normally-Closed offers “fail-
safe” operation.
Contact Memco to discuss direct connection in
more detail.
Fig 3: Installation Wiring (timeout enabled)
TO DOOR OPERATOR OR LIFT CONTROLLER
MODEL 280 or 281 Power Supply
Fig 4: Using a Memco Power Supply
TX CABLE
0V - ORANGE
+12V - RED
TRIG - BLUE
LINK - WHITE or GREEN
RX CABLE
0V - ORANGE
+12V - YELLOW (Timeout Enabled)
LINK - WHITE or GREEN
Power Supply
Door Re-Open
Circuit
TO LIFT CONTROLLER
OR DOOR OPERATOR
DOOR RE-OPEN
DC SUPPLY (11-30V)
0V
ORANGE ‘0V’
YELLOW ‘Timeout’
WHITE or GREEN ‘Link’
‘DC Supply’ RED
‘Link’ WHITE or GREEN
‘0V’ ORANGE
‘Trig Output’ BLUE
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