1.1 Electrical Requirements

The TURAG-Feldbus bus uses the RS485 standard for data transmission, which allows the construction of a differential bus.

The signal coding is based on the possibilities of UART:

• The data transfer takes place in frames.
• A frame consists of a start bit, 8 data bits and a stop bit.
• One start bit equals 0,
• a stop bit logical 1,
• as well as the idle state on the bus.
• The length of a bit is determined by the baud rate set for all bus subscribers. The baud rate can vary from bus to bus, but is the same for all participants on a bus.

On the bus exactly one master and a finite number of slaves are connected.

• All bus subscribers must release the bus immediately after sending a packet.

Notes on electrical details of RS485 can be found here.