Shielding And Ground Potential; Interface Technology, Rs-485 Bus Systems - Honeywell 026593.10 Mounting And Connection Instructions

Mounting and Connection Instructions - Door module RS485
2.3

Shielding and ground potential

!
The door module devices are daisy chained via a shielded twisted pair cable.
Please use Cat 5 or better cable for installation.
!
The shielding of the incoming RS-485 cable is to be connected to the shield terminal bar of the door
module. The shielding of the outgoing RS-485 cable is not connected.
!
The shield terminal bar in each door module must be connected to a separate PE.
!
The shielding of the reader line is
connected on one side to the
shield terminal bar in the door
module.
2.4

Interface technology, RS-485 bus systems

The RS 485 interface used is a bidirectional interface with bus capability. Up to 32 devices can be connected
which can be transmitters as well as receivers. The max. cable lenght of the RS-485 bus data line can be up to
1200m.
The door module has no electrically isolated RS485 interface. If problems with data transmission to the
ACS-8 should occur, a potential separation module (Item No. 026595.10) should be used (see chapter 10.),
note the additional installation instructions in the ACS-8 Installation instructions.
General information:
The RS-485 bus system corresponds to a multipoint connection. Multipoint connection means that
several controllers are communicating with each other. A star-shaped cabling of the door modules
is not allowed.
The line ends of the bus data line must be set with a 120 Ohm terminating resistor. The
terminating resistors can be set on the last bus-user of the bus data line by means of
jumpers at the interface.
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