cias MANTA - Page 48

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CIAS Elettronica S.r.l. Ed. 1.5
Installation Handbook Page 47 of 57 MANTA 50 – 80
3.4 Serial Line RS-485
3.4.1 RS – 485 Network Connection Interface
A standard RS 485 serial interface is provided on both transmitter and receiver of the MANTA
barrier. The communication parameters are the following:
Mode: Asynchronous - Half-Duplex
Baud rate: 9600 b/s
Character length: 8bit
Parity control: No Parity
Stop bit: 1
3.4.2 RS -485 Serial Line connections
The cable interconnections should be “multi-drop” type (BUS), and the branches for connection of
the units as short as possible. Connect to terminal 4 “LO” (“RS 485 –“ negative data line ); to
terminal 3 “LH” (“RS 485+” positive data line ) and to terminal 2 “GND” (data ground line) on
terminal block MS2 on the Receiver and Transmitter PCB. To connect this serial line to a PC it is
necessary to use an RS485/USB converter.
Cable for connecting the barriers
To a maintenance P.C. with WAVE
-
TEST2 SW
Interface
Terminals
MS2
RS485/USB
Converter
Terminals
N°
N°
Symbol
Function
1
+13,8
Powe
r (13,8 V
)
2
1
GND
Data/power ground
3
2 LH 485 Data Line High for RS 485
4
3
LO 485
Data Line Low for RS 485
3.4.3 Network Configuration and Signal Repeaters
The interconnection cable for barrier management via a remote P.C. must be suitable for a
RS485 serial data line, i.e., it must be a low capacity cable with twisted and shielded wires
(70 pF/mt .) for example “Belden 9842”.The limit distance for the RS 485 connection is 1200
meters.
For longer distances use one or more interface Regenerators (BUS REP), see figure below. The
cable configuration must be of the BUS type, and the branches for connection of the units as
short as possible. It is possible to configure the cable in different ways: full star; mixed, star and
BUS type, using Repeaters / Regenerators and interface multipliers (BUS REP), see figure
below.
The total number of units (Tx and Rx) that can be connected to the line are 32, for a higher
number of units, it is necessary the use of one or more line regenerator RS 485. This is true also
for cable lengths of more than 1200 metres. Shield connection continuity must be guaranteed to
properly protect the line from induced noise. The shield must be GROUNDED at only one point,
i.e., near the power supply unit.