Schneider Electric VSE 002 user manual RS-485 interface, Termination, Interface type

VSE 002 External RS-485 Module 4 RS-485 interface

4.

4

RS-485 interface

The RS-485 interface supports 2-wire connection. The dip switch S1 is used to switch the termination and signal biasing resistors on or off.

Termination

ON OFF

Interface type

TTL RS-232

Figure 1. Dipswitch positions of VSE 002

The direction control of the RS-485 transceiver is done with the RTS signal or automatically. The automatic direction control turns the transceiver to transmit mode after detecting the falling edge of a 0-bit. The direction is kept in transmit mode for 0,5ms. This enables the use of the automatic mode with 9,6 kb/s and 19.2 kb/s speeds. When the transceiver is changed to receive mode, the RS-485 line changes state to logic 1 state due to the biasing resistors.

VVSE2/EN M/B006