BEA Multibeam dimensions Hardware, Software, Communica, Tion Stucture

COMMUNICA–

TION STUCTURE	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.
		SW mode		OFF	ASCII bus mode
				ON	quick mode
					(House)
		SW2	(baud	OFF	9600bps
		rate)		ON	19200bps
		SW3 et SW4		OFF,OFF	address 0
		(address)		OFF,ON	address 1
				ON,OFF	address 2
				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.