Embedded Systems LogiMachine5 Power - Page 225

225
Examples
Write to port
port:write('test data')
Blocking read (script will block until 10 characters are read)
data=port:read(10)
Timeout read (script will wait for 10 characters for 20 seconds)
data=port:read(10, 20)
Close serial port
port:close()
Resident script, RS-485 echo test
-- open port on first call
if not port then
require('serial')
port = serial.open('/dev/RS485-1', { baudrate = 9600, parity = 'even', duplex = 'half' })
port:flush()
end
-- port ready
if port then
-- read one byte
char = port:read(1, 1)
-- send back if read succeeded
if char then
port:write(char)
end
end
HEX to RS-485 example
require('serial')
port = serial.open('/dev/RS485-1', {
baudrate = 4800,
parity = 'none',
duplex = 'half'
})
cmd = string.char(0xAB, 0xF1, 0xFF, 0xFF, 0xFF, 0xFF, 0xBE, 0xD1, 0x01, 0xFE, 0xFF, 0xFF,
0x0A, 0x24)
cmd = 'ABF1FFFFFFFFBED101FEFFFF0A24'
port:write(cmd)
Check which cmd works for you, as it can be either hex-encoded readable data or hex
representation of binary data. You might also need to change the parity config
http://openrb.com/docs/serial.htm