Siemens SIMATIC NET PROFIBUS manual Topologies with OLMs, Profibus Optical Bus Terminal OBT

Topologies of SIMATIC NET PROFIBUS Networks

PROFIBUS Optical Bus Terminal (OBT)

Using a PROFIBUS optical bus terminal (OBT), an individual PROFIBUS node without an integrated FO port or a PROFIBUS RS-485 segment can be attached to the optical PROFIBUS network (see Figure 2-2 ).

The attachment is made to the RS-485 interface of the OBT using a PROFIBUS cable or a preassembled connecting cable. The OBT is included in the optical PROFIBUS bus via the FO interface.

2.2.2Topologies with OLMs

OLMs

The OLMs have a floating electrical channel (similar to the channels on a repeater) and depending on the version, they have one or two optical channels.

The OLMs are suitable for transmission rates of 9.6 Kbps to 12 Mbps. The transmission rate is detected automatically.

PROFIBUS Networks SIMATIC NET	2-7
6GK1970-5CA20-0AA1 Release 2 05/2000