Keri Systems SB-293 - Manual (Page 26)

Technical Reference Manual – PXL-250 and SB-293 Keri Systems, Inc.
Page 26 P/N: 01836-004 Revision 5.5
7.3.2 Distributed Mounting
Distributed Mounting places a controller near each door. The RS-485 network
communication cable is then routed to every controller on the access control network.
The benefit of distributed mounting is that less cable is needed for the reader and the
necessary inputs and outputs as they are all near the controller. Only the network cable
needs to be routed throughout the installation. The drawback to distributed mounting
is that a location needs to be found near each door for every controller. More effort
may be needed to maintain and secure the controllers.
All controllers need to be mounted in environmentally suitable locations. They require
protection from weather and from temperature/humidity extremes. If a PXL-250
controller is to be used outdoors, it must be installed in a watertight, weatherproof
enclosure. All controllers need at least three feet of separation between the controller
and the controller's power supply. This will prevent EMI radiated by the power supply
from affecting the performance of the controller.
7.4 Installing the Enclosure
The PXL-250 controller enclosure may be installed on any kind of wall material:
wood, sheet-rock, concrete, or metal. Mount the 12 VDC power supply for the PXL-
250 controller three feet or greater from the controller to provide a degree of isolation
from EMI that may be generated by the power supply. Always be aware of sources of
EMI that may affect the operation of the PXL-250 controller and make your
installations away from these sources whenever possible.
The enclosure's mounting holes are found at each corner of the unit (top left, top right,
bottom left, and bottom right). To mark a surface for drilling enclosure mounting
holes, simply place and hold the enclosure in the desired location and with a pencil or
scribe place a mark on the mounting surface at each mounting hole. Note the location
of the enclosure's knockouts (circular, removable plates on the enclosure's base plate)
and remove the knockout that allows you to route your cables into the enclosure in the
easiest, most direct path.