Re: Simulating simple electric circuits

In article <5ae44aF2ku9rtU1@xxxxxxxxxxxxxxxxxx>,
Bjoern Schliessmann <usenet-mail-0306.20.chr0n0ss@xxxxxxxxxxxxxxx>
wrote:

Sounds more familiar than the analog approach. Maybe I misunderstood
something ... but I can't transfer my problem to this way of
thinking yet. My biggest problem is the fact that relays aren't
really interested in voltage, but current.

Also, I find it difficult to transfer this circuit logic to boolean
logic I can contruct logic gates from. Sometimes, electric circuits
are used in different directions.

Yep, the traditional digital simulation techniques don't apply very well
to things like switches and relays. Going with a different approach is
probably cleaner.


I set up the mentioned "controller" which, at the beginning, tries
out all possible ways through the network and saves them. So, for
every possible circuit it knows which switches must be closed and
which relays will work if it's "on". In theory, it should now be
possible to try out every path, tell the relays if they have
voltage/current, and let the relays report back in to the
controller if their status changes so it can again test the
circuits that may have changed. I haven't tried out the last step,
but I will in the next days. Is there any logic error in my
strategy?

Sounds reasonable. Depending on the size of your network, I might not
worry too much about precomputing and saving information. If your
circuit has loops in it (where the output of a later relay circles back
to an earlier relay's coil), then it is possible for the circuit to
oscillate, so you might have to be careful about this. For example, if
your basic simulation flow was:

1) set initial conditions (switches, etc)
2) let power flow through the system
3) determine which relays will be thrown
4) if any relays have changed state, go to 2

Then an oscillating circuit would never quit. You might want to put a
limit on the number of iterations through the loop, or logic that
explicitly checks for oscillation. Or you could analyze the circuit
ahead of time to see whether it has oscillation or not.

Dave
.

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