Somfy RTS 485 to SHAC

Hi,

Having recently acquired a SHAC I have been trying to connect my Somfy RTS 485 transmitter directly. I can't seem to get it working tho, I can't tell if it is a case of not wiring it well or sending the wrong serial string...

I've got it wired as:
Somfy + to SHAC AT
Somfy - to SHAC BT
Somfy GND to SHAC COM

Scripting I'm using:

msg = string.char(0x7F,0xF2,0xFA,0x01,0x00,0x00,0xDA,0x68,0xFA,0xFF,0xFE,0x06,0xA5)
require('serial')
port = serial.open('/dev/RS485', {
baudrate = 4800,
databits = 8,
stopbits = 1,
parity = 'odd',
duplex = 'half'
})
port:flush()
port:write(msg)
port:close()

Anyone have any ideas? It's hard to troubleshoot as I don't get any errors, it just doesn't work. The string works when I had it connected to an USB RS232 to RS485 dongle on my PC.

Thanks,
Pete

 

Hi Peteinau,

Are you running this in an event script?

You could try sending the string as an escaped string like,
msg = ("\x7F\xF2\xFAx01\x00\x00\xDA\x68\xFA\xFF\xFE\x06\xA5")

I think the leading zeros ,0x00 may be an issue when using string.char(),
Other thing would be to insert
log(msg) after port:flush() to see how the string looks in the log

Or use USB to 485 converter and wire the SHAC to that then run a terminal session on your computer to see what you have coming out the SHAC 485 port.

 

The 0x notation is correct for Lua.

You do have a syntax error however in the serial.open. You are missing a quote, comma and open curly bracket:

port = serial.open('/dev/RS485', {
baudrate = 4800,
databits = 8,
stopbits = 1,
parity = 'odd',
duplex = 'half'
})

 

It looks like the forum deletes those characters for some reason

Yours is probably correct then.

 

Lucky someone reads the docs

 

Hi guys, thanks for the input, nice to know that I'm at least on the right path!

I've connected it to the A and B with wires twisted and not twisted but still no luck. I tried wiring my RS485-USB cable to the SHAC to see if it was sending anything but doesn't seem to be either....

Is there something I need to turn on with the SHAC to enable the port or something? I feel like I've missed something basic somewhere.

Thanks in advance for any help!

 

Hi Nick,

Ahhhh... that might indeed be the problem! We have been powering it by USB. I thought it could be powered by POE initially, but that didn't seem to work so we just used USB. Ordered a power supply to supply the power, hopefully it will just work then.

Thanks heaps!

 

Hi Guys,

I've been away travelling but got a power supply connected it up, but I can't see the RS485 LED flash when I transmit/receive. Does that mean I haven't configured something?

Thanks,
Pete