OBT - Optical Bus Terminal

Using the OBT (Optical Bus Terminal), a PROFIBUS station without integrated optical interface is connected to an optical line with PROFIBUS stations with integrated interface and OBT. Existing DP devices are then provided with the advantages of optical data transmission.

The PROFIBUS station is connected to the RS 485 interface of the OBT via a cable terminated at both ends, e.g. connecting cable 830-1T. The OBT is integrated into the optical line using two optical interfaces.

The following optical transmission media can be connected to the OBT:

• Plastic fiber-optic cables can be used up to an individual segment length of 50 m. They can be assembled very easily on site with 2 x 2 Simplex connectors.
• PCF¹⁾ fiber-optic cables can be used for an individual segment length up to 300 m. These cables are preassembled. The OBT supports all PROFIBUS data transfer rates up to 12 Mbit/s.

¹⁾ Also known as HCS® fiber-optic cable. HCS® is a registered trademark of Lucent Technologies.