Phonetics Skymetry WTU-14, Руководство пользователя

Страница: 29 / 114

Figure 7: Sensor connected to a dry contact input]
Any N.O. or N.C. sensor can be attached to the WTU-14 using 18–
24 gauge wire. For distances of 1000' or more, use heavier gauge
wire. When running wire outdoors it is recommended that shielded
cable be used. Connect the shield to a good earth ground or metallic
cold water pipe. The total resistance of the circuit cannot be greater
than 100 ohms. Use wire appropriate for the application. See the
wire length recommendations, later in this chapter.
The WTU-14 may have more than one sensor connected to the same
terminal, however, the normal condition for each sensor on the same
terminal must be identical (either all N.O. or all N.C.).
Normally Closed Sensors
To wire more than one normally closed sensor on one input, they
must be connected in series. Connect a lead from the first sensor to
one of the Dry Contact Inputs on the terminal strip. 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 your last
sensor and connect it to the ground screw on the WTU-14 terminal
strip. See Figure 8.
Multiple N.C. inputs are typically magnetic reed switches to moni-
tor the security of windows and doors.
Chapter 2: Installation
29