Figure 2-7. Two Sensors Wired to Adjacent Inputs
Share the Same Ground Terminal Screw
NOTE
Do not use sensors, switches, or relays that supply
any voltage or current to the Model 1108. Be aware
of proximity to other electrical wires or components
when placing wires that lead from the sensors to the
unit. Avoid running the wires near electrical devices
that use high voltage or current, such as motors,
heavy machinery, etc. This voltage may be inductive-
ly coupled into the sensor wiring and could result in
damage to the the Model 1108’s circuitry. Try to
place wires at least 6 inches from other electrical
wiring or devices.
2.11 Multiple Sensors
The Model 1108 may have more than one sensor connected to the
same alert input, as long as the normal condition for each sensor
on the same alert input is identical (either all N.O. or all N.C.).
However, only one remote temperature sensor can be used on
each input.
When wiring several normally closed sensors on one input, they
must be connected in series. Connect one lead from the first
sensor to the numbered screw of the alert input. Next, take the
other lead from the first sensor and connect it to one lead from
the next sensor. Continue connecting sensors end-to-end until you
have connected all of your sensors. Take the second lead from the
last sensor and connect it to the ground screw on the Model 1108.
See Figure 2-8. Multiple N.C. sensors are typically magnetic reed
switches to monitor the security of windows and doors.
Chapter 2:Installation
27