Reflective Memory (RFM) networks are designed to provide the highly deterministic, tightly timed performance necessary for a variety of distributed simulation and industrial control applications. They have benefited from advances in general-purpose data networks, but they remain an entirely independent technology, driven by different requirements and catering to applications where determinism, implementation simplicity, integration of a number of dissimilar hardware platforms running different operating systems, and a lack of software overhead are key factors.
By using RFM systems, designers are able to eliminate most communication latency and realise drastic improvements in resource utilisation over traditional LAN technologies. The benefit of a low-software, high-speed, hardware-driven network like RFM is extremely low data latency, both overall and between individual network nodes. This low-latency performance is of paramount importance when building real-time systems such as simulators, PLC controller systems or test stands.
RFM networks can be configured in either Ring or Star topology. The RFM Ring architecture is capable of data transfer rates of 170 MB/s over fiber-optic media. It is not a collision-based bus arbitration system as most Ethernet systems are, so it avoids the complexities of queuing and checking data packets. This topology also ensures proper connectivity and does not impose additional loading restrictions or termination.
The Star topology uses the ACC-5595 bypass hub. With the fiber-optic hub, the RFM network will continue to operate even if a node has been turned off. The hub automatically bypasses any network node that ceases operation to ensure data continues to the next node in the network maintaining the integrity of the ring. Hubs can be cascaded, permitting a managed hub array with up to 256 nodes. Each port regenerates the serial optical signal, eliminating problems with insertion losses and cable attenuation. Signal regeneration also reduces jitter.
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