Rs-485 Bus System With Several Users; Synchronization - Honeywell IDENT-KEY 3 Montage, Anschluss, Anleitung

Mounting and Connection Instructions IK3 Evaluation Unit Conventional
7.5.4 RS-485 bus system with several readers
If several readers are used, the usual RS-485
Note Chapters 7.5.1 and 7.5.2!
Example 1: The
The end of line resistor of the
RS-485
reader
120 W
VT = Distributor
Example 2: The EU is located somewhere between the RS-485 bus line and
beginning.
In this case, the end of line resistor of the EU must be deactivated. For this
purpose,
Install a 120
RS-485
reader
120 W
VT = Distributor
7.5.5

Synchronization

In order to prevent densely packed readers from affecting one another, they must be connected to
one another via the "Synchronization" line (black). Up to 4 readers can be synchronized in this
manner.
Synchronization is required at a distance of
The transponder that is identified first has priority during the read/write process. The other readers
involved are inactive. After a period of 5 sec. they are reactivated.
reader 1
black
Synchronization line
EU is located at the beginning
A B
6 m max.
VT
remove both plug-in bridges
W
end of line resistor from data line A to B in the remotest distributor.
A B
6 m max.
VT
(only if supported by the
reader 2
black
bus regulations are applicable.
of the RS-485
EU is used (PL3 plugged).
RS-485
reader
A B
VT
Bus cable 2000 m max.
from the PL3.
Module
A
B
Bus cable 2000 m max.
reader)
£1 m
(approximate value).
bus line.
Module
A
PL3
RS-485
PL3
B
not at the
RS-485
reader
A B
6 m max.
VT
RS-485
reader 3
black
41
120 W
120 W
max. 4