Mounting with installation instructions
k4evo707en-2012-07
25
3.5 Installation
instructions
for the communication connections
3.5.1 RS-485
cabling
IMPORTANT
Remote and Compact Readers are connected to the parent control unit via a 2-wire party line
connection (RS-485).
Please observe the local legal regulations (e.g. VDE) when installing components. Information on
structured cabling can be found in standard EN 50173.
A standard category 5 cable with 2 conductor pairs, AWG 24 (0.6 wire Ø), and S
‑
UTP design
(Screened Unshielded Twisted Pair), must be used for cable connections. This cable is fitted with a
foil screen (screened). The individual conductor pairs are not shielded from each other
(unshielded). Two color-coded conductors are twisted together in each case (twisted pairs).
Please note that the foil screen is connected by means of a sheath wire. To avoid short circuits, the
sheath wire should be insulated with a heat-shrinkable tube, for example.
Lines A and B are routed as a twisted pair of conductors and are not transposed.
If multiple remote and Compact Readers are to be connected to a parent control unit, either
a bus cabling or a star cabling arrangement can be used.
Depending on the cabling arrangement used, the terminating resistor will need to be adjusted
accordingly on the parent control unit and the remote and Compact Reader
3.5.1.1 Examples of bus cabling
The terminating resistor is adjusted either at the DIP switch or the jumper.
With 1 bus line
Set
the
terminating resistors
on the first and last device to
120
Ω
and all the others to
open
Connect
the
shielding of the RS-485 cables
on the parent control unit and connected devices
to connection
C
(common); connect the
shieldings
of the RS-485 cables between the devices
to each other
Max. length between the parent control unit and the last device is 1,200 m
There should be no stubs (branches) in a bus if possible
