On 15 May 2015 at 07:26, alex chiosso <achio...@gmail.com> wrote:

> And when an where the logic elaboration should be ?

There isn't any HAL logic elaboration as you seem to be describing it.

All the HAL logic is handled by individual components. Those
components read their inputs and update their outputs one by one in
the order they are placed in the thread.

(Some components have more than one "function" and strictly-speaking
it is the functions that execute in the order they are added to the
thread)

What I am saying is that there is that the sequence that things appear
in the HAL files has little bearing on the sequence in which they
happen.
When LinuxCNC starts it reads through all the HAL files in sequence
and sets up all the HAL connections. This is a one-time process at
startup, and from that point on the HAL file is not looked at again.
It is a mistake to imagine that the HAL file is somehow "interpreted"
every cycle as some people seem to. This is why it isn't a programming
language.

If there are two HAL files, and the first contains:

addf parport.0.read thread1
addf and2.0  thread1
addf parport.0.write

and a the second contains

addf or2.0

Then the sequence is that the parport is scanned and the
parport.0.pin-in-NN pin values are updated
Then the and2.0 funsction runs, reading its inputs and updating the outputs
Then the parport.0.write function runs, updating the voltages on the
parport output pins.
Then the or2.0 function runs, reading its inputs and writing its outputs.

I rather worry that my original intention of trying to make HAL
simpler to understand has just become subverted by discussion of
technical details that were not part of the original question at all.


-- 
atp
If you can't fix it, you don't own it.
http://www.ifixit.com/Manifesto

------------------------------------------------------------------------------
One dashboard for servers and applications across Physical-Virtual-Cloud 
Widest out-of-the-box monitoring support with 50+ applications
Performance metrics, stats and reports that give you Actionable Insights
Deep dive visibility with transaction tracing using APM Insight.
http://ad.doubleclick.net/ddm/clk/290420510;117567292;y
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Reply via email to