Siemens has developed new optical link modules (OLM) for Profibus networks. The OLM P22 and OLM G22 modules each have two optical Profibus interfaces using bayonet fiber optic connector (BFOC) technology and two electrical interfaces of the sub-D type. This enables two separate electronic Profibus segments to be integrated into one optical network structure, such as a redundant ring. Whereas the OLM P22 version supports plastic fiber-optic cable (FOC), the OLM G22 is designed for glass fiber-optic cable. Both have a signal contact as a measurement terminal with which the optical signal quality can be monitored. The Siemens Profibus OLMs enable optical Profibus networks to be constructed using line, star and redundant ring structures. The transmission rate of a fiber-optic link of up to three kilometers in length is up to 12 Megabaud/second and does not depend on the distance.
Edited by: Jürgen Wirtz
