socomec COUNTIS E23 - 8 Communication; General Information; RS485 Rules

12 EN
COUNTIS E23/E24 - 545877A - SOCOMEC
8. COMMUNICATION
8.1. General information
The Modbus communication available on the COUNTIS E23/E24 communicates via an RS485 series link (2 or 3
wires) which is used to operate devices from a PC or an API.
In a standard conguration an RS485 connection is used to connect 32 devices to a PC or a controller over 1200
metres.
+ - NC
N 1
+ - NC
N 2
+ - NC
N n
+ - NC
N 1
+ - NC NC - + + - NC
N n
Programmable
machines
Programmable
machines
Other systems
Other systems
Repeater
8.2. RS485 rules
A LIYCY shielded twisted pair must be used. We recommend using a shielded twisted pair with a general LIYCY-CY
shielding in an environment where there is interference or in a very long network with a number of devices.
If the distance of 1200 m is exceeded and/or the number of devices is greater than 32, a repeater must be added to
enable additional devices to be connected.
A 120 Ohm resistor must be xed at both ends of the connection.