Siemens Bewator Entro Series, Installation Manual, Page: 17 / 48

Planning a wireless application
17
Siemens AB
Security Products 03.2014
4.4 Placing the SR35i
In a system with
both
hard-wired and wireless units, if possible locate the SR35i in
the best position for wireless communication, i.e. generally in the middle of the ar-
ea it is to control. If this is not possible, additional RF9 and/or SR35i units may be
required.
Clearly the RF30-EM units cannot be moved. If the signal strength is inadequate
the SR35i may have to be moved or the site completed with one (or more) RF9
routers. Note that if any RF9 have been mounted already the SR35i should not be
moved.
Also note that a SR35i controlling its full complement of
32 wireless doors
needs
at least two RF9 , because each SR35i directly only can manage six routers and
14 door units. It is usually preferable to use more SR35i and RF9 units.
4.5 Placing the RF9
RF9 amplifies the signal and so enables the distance between wireless units to be
increased. System test may show that more RF9 routers are needed. Up to four
RF9 can be placed between one SR35i and a RF39-EM.
Fig. 5 Maximum four RF9 “in a row” (= five hops)
To achieve the best radio performance in the horizontal plane the RF9 should be
mounted high up on a wall Ceiling mounting should normally be avoided (see RF9
– bad and good positioning page 20. Always try to place RF9 centrally between the
nearest units it is to communicate with. In some cases the RF9 can be considered
as working like a mirror, bending the signal round a corner.
It is important that there are sufficient routers to reach the RF30-EM furthest away
from the SR35i.
It is good practice to start at the SR35i when adding RF9.
Remember that each RF9 must have a
power supply and be configured with the
same Segment ID as the SR35i.
Because the communication in a system strives to find the best route, two nearby
RF9 routers can act as backup for each other.
Also consider the risk for a signal to be sent via windows (outdoor in corners)
which may degrade the signal when raining because water influences the signal
negative.