Re: [Advert] [BulkBuy] Low Cost RS232 Serial to EthernetConvertors

[Dave McLaughlin <dave@xxxxxxx>]

Hi Stephen,

You could just about get away with sending 9600 baud RS232 along about
100m of cable, but you would be very susceptible to noise with this.
RS232 was only designed for shortish distances. In your case RS485 would
better suit your needs as it can travel much longer distances and at
higher speeds. I have used RS485 on a 10,000 foot umbilical at 9600 with
no data loss. Being multi drop, it also lends itself to a 2 wire network
as RS232 is really only designed for point to point between 2 devices as
there is no control over the transmit lines activation.

Another option may be CAN bus if you are talking about a simple control
system for valves and temperature.
http://www.embeddedcomputer.co.uk/Projects/CAN_Bus/can_bus.html
is my
website and this shows my own system. The guys on this list also have
xPL and xAP which would lend itself to a microcontroller interface too.
Needs much more code space, but can be done with todays modern
microcontrollers with loads of flash rom. There are quite a few lower
cost options out there.

Regards
Dave...
---

Very funny Scotty, now beam down my clothes...!!
---
http://www.v8carlton.com
http://www.embeddedcomputer.co.uk
---


Stephen wrote:

> On Tue, 6 Jan 2004 15:03:39 -0000, you wrote:
>
> Hi,
>
> These sound great but after thinking about it a bit more I wonder: if
> you have got lots of spare cable in situ ready to connect one of these
> to, why not just wire a serial port into that cable directly? Isn't
> the beauty of serial transfer that it can go over long distance?
>
> One day I'd like to have serial thermometers and r232 controlled
> radiator valves in every room; this device sounds wonderful but would
> cost a fortune if I bought one for each room!



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