RE: Electronics decoding of outputs

["Mick Furlong" <hiltoneltd@xxxxxxx>]

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@xxxxxxxSent: 07 June 2002 16:38
To: ukha_d@xxxxxxxSubject: 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 the 4th output i.e. set up your address and then trigger it. Lots of 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@xxxxxxxDate: Fri, 7 Jun 2002 15:55:23 +0100
To: ukha_d@xxxxxxxSubject: [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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