Specifications

9.2. MASTER – SLAVE with several Masters

The behaviour of Master and Slave is exactly the same as in the previous scenario, i.e. a Slave always

responds to the address from which the request was sent. If by chance two simultaneous requests

from different Masters are received by a slave radiomodem, the RipEX radio modem waits for the first

reply from the connected SCADA device before transmitting the request which arrived second. The

500 ms timeout applies again, i.e. when there is no reply for the first request, the second one is trans-

mitted after the timeout expires.

9.3. MASTER – MASTER

The Master - Master communication is possible. The translation of addresses is proceeded with every

packet incoming to the RipEX radio modem from connected SCADA equipment, thus it is suitable for

SCADA protocols containing the destination address in all packets.

The Poll Response Control has to be set to OFF for the MASTER-MASTER type of communication.

9.4. MASTER UNI – ASYNC LINK SLAVES

The combination of the UNI and the ASYNC LINK protocols is useful for networks where one application

master communicates with many slaves and the slaves are allowed to spontaneously send messages

to the master. The UNI-Master RipEX§s address is configured as the ASYNC LINK protocol destination

address at all the slaves. This arrangement makes the syntax of application protocol messages generated

by slave completely arbitrary. All slave messages are transparently delivered to the application master.

UNI protocol