Re: state notation code flags

[Patrick Thomas <thomas_p@ligo-wa.caltech.edu>]

It does seem to be related to that other variable, and occurs even if it 
is set to some constant instead. But I can't figure how it can be 
setting anything to do with the first variable. I'm going to write a 
piece of shorter test code...
Mark Rivers wrote:
> I don't think the fact that variable 1 was set to variable2 is relevant.
>
> But if you do a pvPut on variable1 that could cause variable2 to change
> in your IOC, depending on the database logic, etc.  When the event flag
> is set on variable2 is the value changing?
>
> Here is a way to help figure it out:  run the following EPICS command
> from the shell:
>
> camonitor variable2
>
> That will print a message every time a monitor is sent for variable2.
> It should print a message each time you get an event on variable2 in
> your SNL program.
>
> Mark
>
>
> -----Original Message-----
> From: Patrick Thomas [mailto:thomas_p@ligo-wa.caltech.edu] 
> Sent: Friday, October 02, 2009 4:47 PM
> To: Mark Rivers
> Cc: tech-talk@aps.anl.gov
> Subject: Re: state notation code flags
>
> I think I have it narrowed down. It appears that when I set variable1 
> equal to variable2 and variable2 has a flag synced to it (variable1 does
> not), and then do a pvPut on variable1, sometimes the flag is set on 
> variable2 and sometimes it isn't. Am I correct? Why does this occur?
> Thank you,
> Patrick
>
> Mark Rivers wrote:
>   
> > Patrick,
> >
> > Event flags can be explicitly set, which is typically used to allow
> > communication between state sets.  Or event flags can be synced to a
> >     
> PV,
>   
> > and will be set whenever a monitor is received for that PV, as in the
> > example I sent you.
> >
> > You can use the efTest() function outside of a when statement, just
> >     
> like
>   
> > any other function.
> >
> > Mark
> >
> >
> > -----Original Message-----
> > From: Patrick Thomas [mailto:thomas_p@ligo-wa.caltech.edu] 
> > Sent: Thursday, October 01, 2009 5:20 PM
> > To: Mark Rivers
> > Cc: tech-talk@aps.anl.gov
> > Subject: Re: state notation code flags
> >
> > Hi Mark,
> >
> > Are the flags on a monitored variable set whenever the monitored 
> > variable is used in the code, including a pvPut, pvGet, assignment, 
> > calculation, or print statement? Is there a way to test if the flag is
> >     
>   
> > set besides an efTest in a when statement?
> >
> > Thank you,
> > Patrick
> >
> > Mark Rivers wrote:
> >   
> >     
> > > Hio Patrick,
> > >
> > > Here are some code snippets from one of my SNL programs.  It has a
> > >     
> > >       
> > variable nelements assigned to a PV, and a monitor on that PV.  It has
> > an event flag, nelementsMon that is synced to nelements.  Whenever
> > nelements changes the event flag will be set.  In the init state I
> >     
> clear
>   
> > the event flag, just to be sure it is clear when the SNL code starts
> > running (after all PVs connect).  I then use efTestAndClear in a when
> > statement to take actions when that event flag is set, and to clear
> >     
> it.
>   
> > This works fine for me.
> >   
> >     
> > > int     nelements;   assign nelements    to "{P}{R}Nelements.VAL";
> > > monitor nelements;
> > > evflag nelementsMon;    sync nelements  nelementsMon;
> > >
> > >
> > >     /* Initialize things when first starting */
> > >     state init {
> > >         when() {
> > >             /* Clear all event flags */
> > > ...
> > >
> > >             efClear(nelementsMon);
> > >         } state monitor_inputs
> > >     }
> > >
> > >
> > > ...
> > >
> > >     state monitor_inputs {
> > >
> > > ...
> > >
> > >         when(efTestAndClear(nelementsMon) && (nelements>=1)) {
> > >             /* If nelements changes, then change endPulses to this
> > >     
> > >       
> > value,
> >   
> >     
> > >              * since this is what the user normally wants.  endPulses
> > >     
> > >       
> > can be
> >   
> >     
> > >              * changed again after changing nelements if this is
> > >     
> > >       
> > desired. */
> >   
> >     
> > >             if (moveMode == MOVE_MODE_RELATIVE)
> > >                 endPulses = nelements;
> > >             else
> > >                 endPulses = nelements-1;
> > >             pvPut(endPulses);
> > >         } state monitor_inputs
> > >     }
> > >
> > > Mark
> > >
> > > ________________________________
> > >
> > > From: tech-talk-bounces@aps.anl.gov on behalf of Patrick Thomas
> > > Sent: Wed 9/30/2009 10:35 PM
> > > To: tech-talk@aps.anl.gov
> > > Subject: state notation code flags
> > >
> > >
> > >
> > > Hi,
> > >
> > > I was wondering if there is a way to track at what point in the state
> > > notation code evflags are getting set and cleared, or if someone
> > >       
> could
>   
> > > clarify under what conditions they get set. I'm having trouble with
> > >     
> > >       
> > them
> >   
> >     
> > > getting set somewhere and not being cleared, but I'm not sure where.
> > >
> > > Thank you,
> > > Patrick
> > >
> > >
> > >   
> > >     
> > >       
> >   
> >     
>