DMP Electronics 7872, Installation Manual

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Installing the Keypad
All DMP keypad housings are designed to easily install on any single–gang switch box or flat
surface. Figure 3 shows the keypad housing base mounting hole locations.
Wiring Specifications for Keypad Bus
When planning a keypad bus installation, keep in mind the following specifications:
1. DMP recommends using 18 or 22–gauge, unshielded wire for all keypad and
LX–Bus circuits. Do not use twisted pair or shielded wire for LX–Bus and keypad
bus data circuits. To maintain auxiliary power integrity when using 22–gauge wire
with a Model 7872 or 7873, do not exceed 225 feet. When using 18–gauge wire, do
not exceed 500 feet. Install an additional power supply to increase the wire length
or add devices.
2. Maximum distance for any one circuit (length of wire) is 2,500 feet regardless of
the wire gauge. This distance can be in the form of one long wire run or multiple
branches with all wiring totaling no more than 2,500 feet. As wire distance from
the panel increases, DC voltage on the wire decreases.
3. Maximum number of devices per 2,500 feet circuit is 40.
Note:
Each panel allows a specific number of supervised keypads. Add additional
keypads in the unsupervised mode. Refer to the panel Installation Guide for the
specific number of supervised keypads allowed.
Installing the Keypad