Configuration example of an optical ring combined with an electrical network

A ring structure of the optical network provides fault tolerance since communication is not interrupted in the event that the cable is damaged at one point or interrupted. Electrical bus segments are incorporated into the optical ring using up to 122 optical link modules (OLM). Depending on the version of the OLMs and the bus cable, the distance between two OLMs can be up to 15 km. A maximum of 32 electrical bus participants can be operated on one OLM.

The configuration example shows a typical addressing scheme with mixed transmission technologies. Although OLMs are electrical participants within their respective segment, they are not assigned a PROFIBUS slave address.

Optical Link Module OLM/G22

Optical Link Modules

Optical Link Modules (OLM) permit the construction of optical and hybrid (electrical/optical) networks in line, ring or star topology.

OLMs can be combined with each other and individual stations or complete electrical segments can be integrated into the optical PROFIBUS network through an electrical interface.

OLMs are available with one (P11/G11) or two (P12/G12/G22) fiber-optic (FO) interfaces with BFOC connections. Depending on the version, they are suitable for the following distances when combined with the correspondingly specified plastic/glass fiber-optic cables:

We preferably recommend the OLM/G12 as the standard component for optical PROFIBUS networks indoors and outdoors.

The OLMs have a compact metal housing suitable for DIN rail assembly. They automatically recognize all PROFIBUS data transfer rates. Faults can be rapidly located as follows:

• Display of module status via floating signaling contact
• Checking of FO link quality (loss per section) via test output for optical receivers for logging and plausibility checks.

Further information and detailed technical specifications on the various OLM versions can be found in Catalog IK PI, chapter "PROFIBUS", section "Network components for PROFIBUS - Optical networks with OLM".

Bus cables

Suitable for the OLM/G12, fiber-optic cables (FOC) made of glass with 2 multi-mode fibers are preferably used for optical PROFIBUS networks indoors and outdoors.

The standard FIBER OPTIC CABLE is available in fixed lengths up to 2 000 m. It is preassembled with 4 BFOC connectors. A BFOC connector set with 20 connectors is available as an accessory.

Further fiber-optic cables as well as detailed technical specifications can be found in the IK PI Catalog, chapter "PROFIBUS", section "Network components for PROFIBUS - Optical networks".