solution 1
POF is an established medium in industrial control networks due to its high reliability in even the most rugged environments besides the following obvious advantages:
1, POF is insensitive to electromagnetic fields and tensures error-free data communication in every circumstance. POF is immune to RF noise
2, Flexible and shock/vibration resistant
3, Standard compliancy: POF is made of insulting material and can share conduits with power lines, complying with the international standards(EIA/TIA 569, CENELEC EN 50174-2.popularity, and gradually replacing wires
4, Remote powder supply. The hybrid cable  contains 2 copper wires and 2 POF cables, allows simultaneous transmission of video and power supply
5, No cable grounding: POF needs no grounding, because it doesn’t conduct current and acts as an opto-isolation device
6, Easy to install and doesn’t need maintenance
7, Withstand a million bending cycles
    POF cable has been used in industrial control networks for over 15 years. Many proprietary networks were configured on the factory floor to connect controllers to devices and sensors to monitor data and provide simple control feedback to production lines. Growth accelerated when standards organizations such as Profibus, Interbus, ControlNet and SERCOS adopted POF as low cost link media for electrically noisy and performance critical applications.
     It is estimated that the world wide market for POF data links in industrial control networks will grow from $133 million in 2002 to $282 million in 2006, an annual growth rate of 21%/year from 2002 to 2006.
  • Industrial control bus system
    Modern factories are controlled by sophisticated electronic systems, employing sensors, actuators and PLC linked via RS-232, RS-485, CAN, Profibus, industrial Ethernet, etc. The various sector groups such as Profibus, Interbus and ControNet are expected to provide the level of standardization necessary for the rapid growth of optical copper link replacements. Organizations such as ProfiNet, Interbus Club, ControlNet International, IOANA and ODVA are defining interface specifications to integrate Ethernet with the widely deployed Profibus, Interbus, ControlNet, SERCOS and DeviceNet field bus standards to improve interperability and lower the costs.
   PROFInet and ControlNet are implementing standards to extend Ethernet from the enterprise to the control, device and sensor level of the automation information hierarchy and to be compatible with the large base of existing field bus standard data links.
   SERCOS is the only internationally approved communication standard for motion control. POF is being used as the transmission medium in a communication standard known as SERCOS. In Germany, the Serial Realtime Communication System (SERCOS) interface was standardized in 1989 by major manufacturers of industrial numerical controls and drives under the Machine Tool Builders ad Electronics and Electrical Manufactures's association (VDW and ZWEI). Digital audio SERCOS is easily covered by conventional plastic optical fiber link technology. The fiber has a step-index profile with a numerical aperture of 0.5 and a typical attenuation with 650 nm collimated light of less than 200 dB/Km. But the bandwidth is limited to about 40Mbps over 100 meters, mainly because of modal dispersion. The transceiver employs low cost 660 nm LED sources based on GaAsP technology. It has couples optical output power in the 10dBM range with slow response time, so these conventional components cannot support high-speed peripheral links operated at 100 to 156 Mbps.
    From 10 Mbps to 400 Mbps, plastic optical fiber (POF) solutions for high speed short and moderate distance data links are cost competitive with copper cable.  
  • Ethernet (IEEE802.3)
    Factory automation requires the most robust media and infrastructure available. Plant floor applications may also have millisecond timing requirements making deterministic data transmission and processing essential. Ethernet is a multi-purpose  and most widespread communication protocol that has become the data standard for home, houses, office  networking. Ethernet has the capacity to identify transimission errors and , in real time, auto-negotiates the betrate, reducing it when the line is disturbed. Ethernet is now recognized as the network of choice outside the office for its many strengths. In the late 1990s-2000, industrial Ethernet products began to serve the communication requirements of industrial customers, replacing or supplementing legacy fieldbus protocols such as Profibus. The proliferation of PLCs with Ethernet ports has helped to drive the widespread adoption of Industrial Ethernet in many markets.
     POF, together with Ethernet, guarantees  a speed of true 100 Mbps in every situation. In contrast, with copper and environmental noises, maximum theoretical speed (100Mbps) isn’t the actual speed.
  • Ancillary components
   When contemplating the use of fiber optic rather than copper cabling for industrial applications, the question of protection from the environment is key. Not only do the cables themselves have to withstand potentially harsh industrial conditions, but also their ancillary components such as connectors and transceivers must meet stringent performance standards and not allow the optical path to be degraded.
   Designers could find a number of different manufactures for Fiber-Optics Transceivers (FOTs) designed to provide fast Ethernet (100Mbps) over POF. New fashion FOT can solve the compatibility problem of a common interface standard both electrically and physically.  Micrel Semiconductor offers such FOTs, well suited for POF transceivers.
   The media converters and repeaters suppliers include Reich & De-Massari AG, Homefiber digital Networks, Diemount GmbH, Luceat, Newnex, Motorola, Firecomms, Electronic Links International, etc. POF connectors suppliers include Molex, Electronics Links International, Avago, Tyco, Sharp and Reichle & De-Massari AG, etc.