![background image](http://html1.mh-extra.com/html/abb/rs485-modbus-adapter/rs485-modbus-adapter_user-manual_3351075004.webp)
4 – Overview
RS485 User guide
To be connected to RVT RS232
input (optical transceiver)
RVT RS485 Modbus adapter
To be connected to RVT power
supply connector
Please note that if the RVT is already installed and connected, the RVT power supply has
to be switched OFF during the Modbus adapter connection. [Detailed information on
RVT mounting is available in “RVT – Installation and Operating Instructions”]
2.3 Modbus adapter wiring
A proper cable must be used for the connection between the RVT Modbus adapter and
the Modbus master. For a RS-485 connection and up to 1200 m (4000 ft), a 24 AWG
twisted pair with foil shield and drain wire on each pair is usually required (Belden 9841
for 2-wire and 9729 for 4-wire or equiv.) [Detailed information is available in “RVT Modbus
RS485 adapter – Installation and Start up Guide”]
Please note that if the RVT is already installed and connected, the RVT power supply has
to be switched OFF during the Modbus adapter connection. [Detailed information on
RVT wiring is available in “RVT – Installation and Operating Instructions”].