Rs-485 Bus; Voltage Supply Of Rs-485 Bus Readers; Line Length And End Of Line Resistors; Direct Connection - Honeywell IDENT-KEY 3 Montage, Anschluss, Anleitung

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7.5

RS-485 bus

A plug is soldered to the cable of the operating unit at the factory specially for testing and pre-
assembly equipment. For final installation, it usually requires cutting off.
7.5.1

Voltage supply of RS-485 bus readers

NOTE: The total current consumption
Therefore only one reader
preferably in an unsecured area).
More readers r must be supplied via an external source (e.g. U_ext from the control panel or a
separate power supply unit).
AC readers must always be supplied
7.5.2

Line length and end of line resistors

The total length of the
Note: The bus line must be closed
For readers that have no connectable end of line resistor (e.g. "Accentic" readers), the resistor must
be installed in a distributor.
The distance between the distributor and the user
A
RS-485 user
B
6 m max.
7.5.3 Direct connection to one reader
Reader types see 4.2.1
F i
1 2 3
4 5 6
7 8 9
3
r 0
Cable length max. 6 m
Shorten cable as required
With this type of connection,
If a cable longer than 6 m is required between reader and EU (max.2000 m possible), a distributor with a
W
120 end of line resistor must be installed in front of the reader (from A to B).
External voltage supply U_ext:
The external source must provide the max. required current to the reader (e.g. time-limited write/read
mode incl. status indication, possibly with background lighting).
Mounting and Connection Instructions IK3 Evaluation Unit Conventional
at connection +U_BDT may not exceed
can be directly supplied by the IK3 EU with 12 V DC via +U_BDT (reader
externally.
RS-485 bus line can be
at both ends
120 W
VT
Distributor
U_ext. from
control panel
RS-485
both plug-in bridges
(max. 4)
up to 2000 m.
W.
with 120
should be max. 6 m
Bus cable 2000 m max.
Do not confuse the data lines A and B,
otherwise the device will not function!
120 W
of PL3 must be plugged.
200 mA .
EU
A
PL3
RS-485
PL3
B
PL3 plugged
W
120 EOL resistor
activated
RS-485
Synchronization
120 W