RE: RE: Electronics decoding of outputs

["i.bird@xxxxxxx" <Ian@xxxxxxx>]

Well, the relay board needs a little more testing and maybe a mod. After
that it is a couple of weeks to get them ,ade so at a guess a month or so
won't be far out.

For the PIC side of things - assuming a simple serial link at 9600 then
that is a couple of nights work. The relay board supplies power for the PIC
and all that is needed then is a serial copnnection and power supply (for
the relay board). I would make a board for the PIC as I don't think at this
stage there would be the demand to make having them done commercially
viable. Say a week or two. The only thing to get in the way is unforseen
problems and family commitments.

I will be posting relay board updates in due course, when you see one
saying nearly done then remind me and will put together the PIC code etc.
You will need to write the PC program to send the codes and read in the
status answers. I would suggest VB as it is simple and others can use it
and modify etc. at will. I will post the codes in due course but they will
be simple e.g. A1 for relay A on. A0 for relay A off.

As a future step I will be running these from RS485 and use a protocol so
the command e.g. A1 will be addressable to a specific PIC chip. This means
you would be able to have many boards and PIC chips all on the same bus and
all individually addressable. This is where the code starts to merge with
the IR repeater code I have been writing over the few months.

Interesting times (I hoipe you think).

Ian B



Original Message:
-----------------
From: Mick Furlong hiltoneltd@xxxxxxx
Date: Fri, 7 Jun 2002 16:43:01 +0100
To: ukha_d@xxxxxxx
Subject: RE: [ukha_d] Electronics decoding of outputs


Sounds like the idea I was toying with is a real pain so I am
definitely
interested Ian, how far in the future is your solution?

Cheers
Mick

  -----Original Message-----
  From: i.bird@xxxxxxx [mailto:i.bird@xxxxxxx]On Behalf Of
i.bird@xxxxxxx
  Sent: 07 June 2002 16:38
  To: ukha_d@xxxxxxx
  Subject: RE: [ukha_d] Electronics decoding of outputs


  Hi Mick

  The answer is yes and no.

  I 'think' there are 4 to 16 decoder chips - there are cirtainly 3 to
8
ones. I don't know without looking in the catalogues.

  And now the BUT(s)

  Using a decoder only you will only be able to change the state of
one
relay at any given time if you have 16. Also with relays, if you remove
the
switching current the relay will turn off. This means you will need
some
type of flip flop which changes state with a pulse to hold the relay in
its
given position. This now presents you with a state question, i.e. is it
on
or off? There is also the question of what are you trying to do -
assuming
these relays controlling the 4 lines swich at normal speeds you will be
sending all sorts of combinations down the decoder as you get to your
final
state. You probably stand to have a load of very confused relays. The
fix
would be to have a three to 8 decoder and then a 'switch' or 'do it'
line
>from
fun challenges like that.

  I have been looking at this recently and you may be better off
building a
PIC controlled board (like my relay board when it gets to production).
This
would give you serial (or 485) control - your choice. If you want to
know
more on this I will expand in another mail. Connect two together under
RS485
and you have 16 relays with status feedback!!

  Ian B



  Original Message:
  -----------------
  From: Mick Furlong hiltoneltd@xxxxxxx
  Date: Fri, 7 Jun 2002 15:55:23 +0100
  To: ukha_d@xxxxxxx
  Subject: [ukha_d] Electronics decoding of outputs


  Ok the same Linux box mentioned in my previous email has 4 outputs
which
are
  relay based potential-free switch contacts. These are rated 1.5A at
230 V
AC
  and 2A at 30VDC.

  What I would like to do is to decode these outputs giving me 
additional
  states (something similar to how frank is doing the HV/IR stuff I
guess)
if
  my math holds up I should be able to control 16 relays using
combinations
of
  the 4 signals.

  Is it as simple as using a set of logic gates to do this?

  Is there a solution on a chip ?

  Any other help?

  btw I am VERY rusty with my electronics....23 years rusty ....so go
easy
on
  me ;)

  Thanks
  Mick



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