avoidance capability, it uses frame acknowledgement, retransmissions and CRC checks to guarantee
data delivery and integrity even under harsh interference conditions on the radio channel.
RipEX works as a standard IP router with 2 independent interfaces: radio and ETH. Each interface has
its own MAC address, IP address and mask.
IP packets are processed according the routing table rules. You can also set the router’s default gateway
(applies to both interfaces) in the routing table.
The COM ports are treated as standard host devices, messages can be delivered to them as UDP
datagrams to selected port numbers. The destination IP address of a COM port is either the IP of ETH
or the IP of a radio interface. The source IP address of outgoing packets from COM ports is always the
IP of the ETH interface.
2.3.2. Functionality example
In the following example, there are two independent SCADA devices connected to RipEX's two COM
ports. 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.
Step 1
FEP sends a request packet for RTU1 through COM2 to
its connected RipEX.
Simultaneously PLC2 sends a packet for PLC1 to RipEX2
through COM1.
Step 2
FEP’s RipEX transmits an addressed packet for RTU1 on
Radio channel.
RipEX1 receives this packet, checks data integrity and
transmits the acknowledgement.
At the same time packet is sent to RTU1 through COM2.
RipEX3 receives this packet too. It doesn’t react, because
this packet is directed to RipEX1 only.
Step 3
RipEX2 waits till previous transaction on Radio channel is
finished (anti-collision mechanism).
Then RipEX2 transmits on Radio channel the addressed
packet for PLC1.
RipEX1 receives this packet, checks data integrity and
transmits acknowledgement.
At the same time packet is sent to PLC1 through COM1.
Simultaneously the reply packet from RTU1 for FEP is re-
ceived on COM2.
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© RACOM s.r.o. – RipEX Radio modem & Router
RipEX in detail
Summary of Contents for RipEX 1.5
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