14
PRÉSENTATION
INTRODUCTION - DARSTELLUNG - PRESENTAZIONE - PRESENTATIE - PRESENTACIÓN - APRESENTAÇÃO
JBUS/MODBUS COMMUNICATION
JBUS/MODBUS MEDIA
GB
In a standard configuration, one RS485
connection enables 32 UL* to be connected
to a PC or PLC over 1200 metres using the JBUS/
MODBUS® protocol.
* 1 UL = 2 COUNTIS E44R.
Recommendations
An LIYCY type shielded twisted pair must be used. In
an environment with interference or on a long network
with a large number of COUNTIS, we recommend
using a shielded twisted pair with general LIYCY-CY
shielding.
If the distance is greater than 1200 m and /or there
are more than 64 COUNTIS, a repeater (1 channel) or
a spark arrester (2 channels) must be connected to
enable the connection of additional COUNTIS with
communication interface over more than 1200 m.
For more information on the connection procedure,
refer to the technical bulletin available on the WEB
site: www.socomec.com
:
R=120Ω
R=120Ω
COUNTIS E44R - Ref.: 538 700 A
Important:
It is essential to connect a resistance of 120 Ohms
to the 2 ends of the connection; this can be found in
the product packaging. Other solutions are available
(modem, fibre optic, etc.); please ask for details.
JBUS/MODBUS protocol
The JBUS/MODBUS protocol operates on a master/slave
structure:
• Reading (Function 3),
• Writing (Function 6 or 16), broadcast option at
address 0.
The communication method is RTU (Remote Terminal
Unit) with hexadecimal characters comprising a minimum
of 8 bits.
JBUS/MODBUS table
File Ref: 538462
Can be downloaded from the web site:
www.socomec.com
RS485 COUNTIS
1200 M or 32 UL
R=120Ω
1200 M or 32 UL
R=120Ω
R=120Ω
R=120Ω
R=120Ω
1200 M or 32 UL