Rs485I Communication Module - LACROIX Sofrel S4W Installation Manual

RS485i communication module

RS485i communication module
This module makes it possible for the RTU to communicate via isolated RS485 link (without power feed) with one or several devices
when equipotential grounding is not guaranteed. This can be the case when 2 communicating devices are located in different buildings.
A 'bus' network topology is required: no looping or star structure configurations.
Any diversions from the main bus must be kept as short as possible (< 10 m).
The communication speed on the link is configurable: From 1,200 to 115,220 bits per second.
Example connection of 2 devices:
Technical specifications
- Cable:
- Use a twisted pair from a wire with screen or shielding.
- Pay attention to polarity.
- Maximum length = 1200 metres (for greater lengths, use repeaters).
For significant distances, install a 120 Ohm resistor Ω in parallel with the devices located at the 2 ends of
the link (for more information, Contact the STC LACROIX Sofrel technical team).
RTU
•
•

: common
• D+: RS485 bus
-
D : RS485 bus
RS485 surge arresters
RS485 bus
RTU