BEA Multibeam - Manual (Page 3)

1. Hardware :
The communication module uses the standard RS485, the driver is a low EMI 250 Kbits-type,
protected against electrostatic discharges.
Up to 32 terminals may be connected on the same BUS line.
The twin-wire communication enables the Half Duplex operating mode.
A dip-switch enables you to choose the operating mode of the MULTIBEAM. Be aware to always
make an “on/off” operation on the MULTIBEAM after each modification to the dip-switches in order to
activate this modification.
OFF ASCII bus mode SW mode
ON quick mode
(House)
OFF 9600bps SW2 (baud
rate) ON 19200bps
OFF,OFF address 0
OFF,ON address 1
ON,OFF address 2
SW3 et SW4
(address)
ON,ON address 3
2. Software :
Dip switches enable you to choose between bus or quick mode.
With the dip-switch you can choose the baud-rate : 9600 or 19200 Bps.
2.1. ASCII BUS mode
The communication and the processing of head signals are asynchronous. The controller leads the
communication and sequentially questions the terminals on the BUS.
Each terminal has a different address. This address can be fixed between 0 and 3 thanks to the two
dip-switches, which can be found on the MULTIBEAM receiving module. The controller interrogation
speed can vary from 33ms to endless time without troubling the process of the module.
In case of communication interruption, the beams keep on working as well as the visualization LEDs.
A delay of 1,5 ms before the MULTIBEAM sends its answer has been added in order to avoid any
trouble on the RS485 line.
Structure of the byte for the ASCII BUS mode
Start bit, 7 data bits, 1 bit of even parity
and 1 stop bit.
Structure of the controller frame to the MULTIBEAM
Header ‘ :’
Address from 0 to 3 (for example '0' '1')
Function ‘0’ ‘0’
Checksum ‘F’ ‘F’ 2's complement (adress + function)
CRLF carriage return et linefeed 0x0d 0x0a
Total : 9 bytes
Structure of the MULTIBEAM frame to the controller
Header ‘ :’
Address from 0 to 3 (for example '0' '1')
Function ‘0’ ‘0’
low detection ’0’ ‘0’ (first 8 beams)
high detection ’0’ ‘0’ (last 8 beams)
Checksum ‘F’ ‘F’ 2's complement (address + function + low detection + high detection)
CRLF carriage return et linefeed 0x0d 0x0a
Total : 13 bytes
The response will be sent 1.5 ms after receiving the demand.
COMMUNICA –
TION STUCTURE