5
figure 4.
Figure 4: Radio network typical configuration
The network is based on ID numbers associated with each robot present in the
radio network. The radio base station ID is always 0. The ID of a radio turret can be set
on the radio turret itself using the ID selector (see the Khepera radio turret user manual
for more details).
The radio turret ID should be never set to 0.
4.4
Radio properties and correct data transmission
The radio channel is a half duplex channel, which means that reception and trans-
mission of data are mutually exclusive. The default state of the radio module is reception.
As soon as data has to be transmitted, the state changes and the data is transmitted.
The state of the radio module is visualized on the RxHF (radio receive) and on the
TxHF (radio transmit) LEDs.
The data transmitted on the radio channel is encapsulated in messages including
information on the type of message, the sender ID, the destination ID, length of data and
a checksum for error correction. The receiver acknowledges the reception of the mes-
sage. The sender considers the message as correctly sent only if acknowledged by the
receiver. If no acknowledgment is received in a given timeout, the message is sent again.
The same procedure is repeated until a maximum number of repetitions is reached. If all
repetitions fail, the message is considered lost.
RS232
Power supply
radio ID: 1 (to be set)
radio ID: 2 (to be set)
radio base ID: 0
