Re: FLOW disciplines and KCL

Implicit equations can also be signal flow - why not?

Jonathan David wrote:
> No, you are confusing implicit equations which support
> having the simulator solve for the solution with
> signal-flow which lets you use
> --- peterl@xpedion.com <peterl@xpedion.com> wrote:
> 
>>I think the original idea behind signal flow is to
> 
> make it an "unknown" 
> 
>>in a differential algebraic equation so it can be
> 
> solved as part of the 
> 
>>system and then used.  As I originally stated,
> 
> something like
> 
>>"V(n1) <+ 2*V(n1) +1;" is definitally allowed.
>>We can then use the simulator as a more general
> 
> solver.
> 
>>NOTE: A signal flow node should be the similar to a
> 
> free quantity in 
> 
>>VHDL-AMS.
>>
>>Peter Liebmann
>>
>>Marq Kole wrote:
>>
>>>Jonathan,
>>>
>>>A resulting limitation for the signal flow
> 
> disciplines connecting to a 
> 
>>>conservative discipline would be that a signal
> 
> flow node can have only 
> 
>>>one conservative instance connected to it, and
> 
> that all signal-flow 
> 
>>>instances need to have the same port direction,
> 
> i.e. all in or all out.
> 
>>>Should an inout port direction not be allowed for
> 
> signal flow models: it 
> 
>>>has to be either in or out. I can image a model
> 
> where a signal-flow port 
> 
>>>is either read or driven, dependent on a parameter
> 
> setting, but it 
> 
>>>cannot read and drive at the same time...
>>>
>>>Regards,
>>>Marq
>>>
>>>
>>>Marq Kole
>>>Competence Leader Analog Simulation, Philips ED&T
>>>
>>>
>>>Marq Kole/EHV/RESEARCH/PHILIPS wrote on 02-06-2006
> 
> 16:08:32:
> 
>>> > Jonathan,
>>> >
>>> > Your reply required some thinking before I
> 
> could answer; I'll also
> 
>>> > copy the reflector as I think this is relevant
> 
> to our discussions.
> 
>>> >
>>> > Regards,
>>> > Marq
>>> >
>>> >
>>> > Marq Kole
>>> > Competence Leader Analog Simulation, Philips
> 
> ED&T
> 
>>> >
>>>
>>> > Jonathan David <jb_david@yahoo.com> wrote on
> 
> 31-05-2006 18:41:25:
> 
>>> >
>>> > > Hi Marq,
>>> > >
>>> > > thanks for the reply. It looks like you
> 
> missed part of
> 
>>> > > my point.
>>> > >
>>> > > Let me ask a question;  For a potential
> 
> nature, do you
> 
>>> > > expect KVL to be obeyed? I do, and I think
> 
> you do
> 
>>> > > also..
>>> > > V(B) = V(A) + V(B,A)
>>> > > V(A,gnd) + V(B,A) + V(gnd,B) = 0;
>>>
>>> > This is not necessarily the KVL: in mathematics
> 
> this is also known
> 
>>> > as associativity. If you consider 0 to be the
> 
> mathematical ground
> 
>>> > i..e reference, then with V(B) = 2 and V(A) = 3
> 
> you say:
> 
>>> >
>>> > 2 = 3 + (2 - 3)
>>> > (3 - 0) + (2 - 3) + (0 - 2) = 0
>>> >  
>>> > > therefor when I flip to the FLOW side, I
> 
> expect KCL to
> 
>>> > > be obeyed.
>>> > > KCL: Sum(I)@node = 0;
>>> > >
>>> > > In fact if it isn't, it wouldn't be possible
> 
> to
> 
>>> > > connect the flow type to the flow connection
> 
> of the
> 
>>> > > compatible conservative discipline.
>>> > >
>>> > > but your example doesn't show a violation.
>>> > > Without the context (how the block is
> 
> connected) we
> 
>>> > > can't talk about KCL.
>>> > > Your example has no context.. its not
> 
> connected up
> 
>>> > > with any thing else, and without the
> 
> connection nodes,
> === Message Truncated === 
>