I'm sorry, I should clarify. It doesn't print the message after sitting
there for a long time. It sometimes prints it when it is started over
again multiple times.
-Patrick
Eric Norum wrote:
I forgot to mention, that I tried your example (with busy loops
removed) on R3.14.11. My test IOC has been sitting there for half an
hour now without printing the message.
On Oct 3, 2009, at 5:13 PM, Eric Norum wrote:
There seems to be a fundamental misunderstanding in your use of the
sequencer. The default action, if no state transition 'when'
statement is true, is to stay in the same state waiting for a
statement to come true. Your examples have lots of statements like:
state clear {
when(efTestAndClear(test_putEvent)) {
efClear(test_putEvent);
} state wait
when () {
} state clear
}
The above code is bad. It sets the sequencer into a busy loop
consuming all available CPU.
I think what you want is the following:
state clear {
when(efTestAndClear(test_putEvent)) {
efClear(test_putEvent);
} state wait
}
This code blocks the sequencer until something 'interesting' happens
at which point it rescans the 'when' statements and checks to see if
any of them are now true.
I suspect that your 'flag' problem is occurring because the busy
loops you've constructed are preventing other threads from getting
the CPU they need.
On Oct 3, 2009, at 4:46 PM, Patrick Thomas wrote:
Hi Mark,
Why does this still sometimes print out the flag?
program sncTest
float test_put;
assign test_put to "H3:TEST_PUT";
monitor test_put;
evflag test_putEvent;
sync test_put test_putEvent;
ss ss1 {
state init {
when () {
efClear(test_putEvent);
test_put = 40;
pvPut(test_put, SYNC);
} state clear
}
state clear {
when(efTestAndClear(test_putEvent)) {
efClear(test_putEvent);
} state wait
when () {
} state clear
}
state wait {
when (efTest(test_putEvent)) {
printf("flag set\n");
} state loop
when () {
} state wait
}
state loop {
when () {
} state loop
}
}
Mark Rivers wrote:
Hi Patrick,
What is it you are trying to do? You are doing both pvPuts and
looking for external changes to the same PV?
If so, then one solution is to ignore events which correspond to
the value that your SNL program set with pvPut, and only act on
events with values that must have been done by some external
agent. Here is an example from one of my programs:
int abort; assign abort to "{P}{R}Abort.VAL";
monitor abort;
evflag abortMon; sync abort abortMon;
...
ss xpsTrajectoryAbort {
state monitorAbort {
when ((efTestAndClear(abortMon)) && (abort==1) &&
(execState==EXECUTE_STATE_EXECUTING)) {
...
abort=0;
pvPut(abort);
} state monitorAbort
}
}
In this case abort can be set to 1 by the user from outside the SNL
program. If that happens then the SNL program takes some
appropriate action, and does a pvPut of abort back to 0. That
would cause another event to be received, but I ignore that event
in the when clause()
when ((efTestAndClear(abortMon)) && (abort==1) &&
(execState==EXECUTE_STATE_EXECUTING)) {
This will always clear event flags on the abort PV, but will only
do the logic inside the when if abort is 1 and execState is
EXECUTE_STATE_EXECUTING.
Mark
________________________________
From: Patrick Thomas [mailto:[email protected]]
Sent: Sat 10/3/2009 12:37 AM
To: Mark Rivers
Cc: [email protected]; [email protected]
Subject: Re: state notation code flags
I see, thank you. So is there a way around this, that is to make sure
the monitors are received and the flag is set before the call to
efClear
is made, or some way to make a particular pvPut not have channel
access
send out monitors for that record?
Mark Rivers wrote:
I think I have figured it out, the following code shows it the most
clearly. Adding SYNC to the pvPut command does not seem to ensure
that
it will finish before the next command is processed:
The pvPut command did "finish" before the efClear command was
executed. That means that it wrote its value to the record, and
processed that record and any records that process as a result of
processing that record. That record told channel access to send
out monitors on that PV to all clients, including your SNL
program. It does NOT wait for those monitors to be received; it
simply requests channel access to send them, which is then done
asynchronously. So the event flag in your SNL program will be set
some time after you do the pvPut. What you are observing is the
expected and documented behavior of EPICS.
Mark
________________________________
From: Patrick Thomas [mailto:[email protected]]
Sent: Fri 10/2/2009 7:03 PM
To: [email protected]
Cc: Mark Rivers; [email protected]
Subject: Re: state notation code flags
I think I have figured it out, the following code shows it the most
clearly. Adding SYNC to the pvPut command does not seem to ensure
that
it will finish before the next command is processed:
program sncTest
float request_maximum_velocity;
assign request_maximum_velocity to "H3:TEST";
monitor request_maximum_velocity;
evflag request_maximum_velocityEvent;
sync request_maximum_velocity request_maximum_velocityEvent;
ss ss1 {
state init {
when () {
efClear(request_maximum_velocityEvent);
request_maximum_velocity = 40;
pvPut(request_maximum_velocity, SYNC);
efClear(request_maximum_velocityEvent);
} state wait
}
state wait {
when () {
if (efTest(request_maximum_velocityEvent)) {
printf("flag set\n");
}
} state wait
}
}
Pete R. Jemian wrote:
sounds a bit off ... show the code
Patrick Thomas wrote:
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:[email protected]] Sent:
Thursday, October 01, 2009 5:20 PM
To: Mark Rivers
Cc: [email protected]
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: [email protected] on behalf of Patrick Thomas
Sent: Wed 9/30/2009 10:35 PM
To: [email protected]
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
--
Eric Norum <[email protected]>
Advanced Photon Source
Argonne National Laboratory
(630) 252-4793
- Replies:
- Re: state notation code flags Eric Norum
- Re: state notation code flags Eric Norum
- References:
- state notation code flags Patrick Thomas
- RE: state notation code flags Mark Rivers
- Re: state notation code flags Patrick Thomas
- RE: state notation code flags Mark Rivers
- Re: state notation code flags Patrick Thomas
- Re: state notation code flags Pete R. Jemian
- Re: state notation code flags Patrick Thomas
- RE: state notation code flags Mark Rivers
- Re: state notation code flags Patrick Thomas
- RE: state notation code flags Mark Rivers
- Re: state notation code flags Patrick Thomas
- Re: state notation code flags Eric Norum
- Re: state notation code flags Eric Norum
- Navigate by Date:
- Prev:
RE: state notation code flags Mark Rivers
- Next:
Re: state notation code flags Eric Norum
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
<2009>
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
- Navigate by Thread:
- Prev:
Re: state notation code flags Eric Norum
- Next:
Re: state notation code flags Eric Norum
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
<2009>
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
|
·
Home
·
News
·
About
·
Base
·
Modules
·
Extensions
·
Distributions
·
Download
·