RACOM RipEX2, Руководство пользователя

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Fig. 5.4: Router - Base driven, Addressing - Serial
5.2.2. Router - Flexible
Router mode with Flexible protocol is suitable for Multipoint networks of all topologies with unlimited
number of repeaters on the way, and all types of network traffic where Multi-master applications and
any combination of simultaneous polling and/or report-by-exception protocols can be used.
Each RipEX2 can access the Radio channel spontaneously using sophisticated algorithms to prevent
collisions when transmitting to the Radio channel. Radio channel access is a proprietary combination
of CSMA and TDMA; the Radio channel is deemed to be free when there is no noise, no interfering
signals and no frames being transmitted by other RipEX2 stations. In this situation, a random selection
of time slots follows and a frame is then transmitted on the Radio channel.
Frame acknowledgement, retransmissions and CRC check, guarantee data delivery and integrity even
under harsh interference conditions on the Radio channel.
5.2.2.1. Functionality example
In the following example, there are two independent SCADA devices connected to RipEX2's ports
(COM and ETH). One is designated RTU (Remote Telemetry Unit) and is assumed to be polled from
the centre by the FEP (Front End Processor). The other is labelled PLC (Programmable Logic Controller)
and is assumed to communicate spontaneously with arbitrary chosen peer PLCs.
47 © RACOM s.r.o. – RipEX2 Radio modem & Router
RipEX2 in detail