AVR-Chat

Chuck

So, are the variables internally determined (for example, from sensors) while the expression is entered by the user such that the symbols (T1, and so forth) are just references to the internal variables?

Jim Wagner
Oregon Research Electronics

On Nov 25, 2012, at 4:23 PM, Chuck Hackett wrote:

> > From: Jim Wagner
> > 
> > Is this an ASCII input or are the variables just pin states? Is the
> expression
> > variable from one time to the next (that is, does the machine have to
> parse
> > the expression) or is the expression set at compile time?
> 
> Expression is in ASCII and is evaluated at run time.
> 
> The "known variables" I referred to are values known at run time - they are,
> in fact, the "occupied" / "unoccupied" state of tracks in a 7.5" railroad -
> this logic is part of the signal system logic.
> 
> So: "(T1 & T2) | T3" evaluates to true if "Track 1 AND Track 2 are occupied,
> OR Track 3 is occupied"
> 
> The expression is part of the configuration data loaded into the control
> node at the time it is configured by the user.
>  
> Cheers,
> 
> Chuck Hackett
> "Good judgment comes from experience, experience comes from bad judgment"
> 7.5" gauge Union Pacific Northern (4-8-4) 844
> http://www.whitetrout.net/Chuck
> 
> 



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