Rs-485 Modbus - Siemens Simatic RTU303xC Series Operating Instructions Manual

4.20.2

RS-485 Modbus

RS485 - Modbus
RS-485
Here, you set the parameters for sending and the frame format.
● Baud rate [bps]
Select the transmission speed:
– 9600
– 19200
– 38400
– 115200
● Parity
– Even
– Odd
● Data bits
– 8 (cannot be changed)
● Stop bits
– 1
– 2
● Activate fail-safe resistors on the bus
If this option is enabled, the internal fail-safe resistors of the RTU are switched on.
This is only necessary in rare cases, for example when connecting Modbus slaves
without galvanic isolation. Note that the power consumption of the RTU increases
significantly when this is enabled, especially if the "Bus active in sleep mode" function is
enabled at the same time.
RTU303xC
Operating Instructions, 06/2019, C79000-G8976-C382-06
Configuration (WBM)
4.20 Extension board
201