Technical data

Chapter 2 – Installation

RS485 and RS232 Adapter Installation and Start-up Guide 2-5

Selecting RS485 or RS232 Mode

The adapter operates either in RS232 mode or in RS485 mode, selectable by a

jumper. As a factory setting, the adapter operates in RS485 mode.

Figure 2-4 Selecting the operating mode.

RS485 Bus Termination

The RS485 bus must be terminated using 120 9 resistors at both ends of the

network. The adapter has built-in termination resistors that can be enabled by

the bus termination switch S1. Refer to 'Earthing and Termination' on page 2-

11. By default, bus termination is enabled (ON).

Figure 2-5 Selecting RS485 termination impedance.

Jumper S3

Mode

RS485

RS232

Bus termination switch