Installation guide

24
MODEL 1101 COMMAND LEM (C-LEM) cont.
Terminals 1, 3, 4, 9, 11, and 12 are connected exactly as for D-LEMs. Terminals B or F require
+12 volts DC, while terminals A or E are negative. Note that the 12 volts DC must have a
common negative with the panel. If you are using the APLEX panel's terminal 28 or 29 as a
negative, then this requirement is met. If you use an auxiliary 12-volt DC power supply, try to
power it from the same branch circuit as the panel. Connect a 2200-ohm (2K2) resistor link from
the auxiliary supply negative to panel terminal 28 or use a 2200-ohm resistor to link terminal A
to terminal 1 on a C-LEM. If more than one C-LEM is powered from the same auxiliary supply,
then only one C-LEM should have the link between A and 1 to avoid ground loops. Terminals 5
and 6 are the dry contacts from the tamper micro switch on the C-LEM printed circuit board.
You may wish to link this micro switch in series with the tamper circuit of a nearby LEM to
supervise the C-LEM cover.
C-LEM MK I (discontinued)
Information on the C-LEM MK I is presented here for reference purposes only. The C-LEM
MK I differs from the MK II version in that the MK I used a 0.5-amp DIL SPST relay connected
to terminals 7 and 8. The MK I C-LEM is distinguished by the rainbow-coloured BCD switch
used to set the address. Normally open (i.e., close on alarm) or normally closed (i.e., open on
alarm) operation is controlled by the brown DIL switch 1. As the MK I was originally designed
to operate from 7 volts DC, terminal 3 should be linked to terminal 2 with a 1N4001 general-
purpose diode or an equivalent. Connect the anode to terminal 3 and the cathode (banded end) to
terminal 2.