Experimental Physics and
Industrial Control System

Tim Mooney <[email protected]> · Tue, 3 Jan 2012 12:59:24 -0600 (CST)

Hi,

seqFlag is just a variable - just a location in RAM that contains a value.  There is no machinery associated with it that would wake up the state set and cause it to execute the 'when' statement.  pv1 has that machinery because it's assigned to a PV and you specified 'monitor'.

Tim

----- Original Message -----
From: "S. Stein" <[email protected]>
To: [email protected]
Sent: Saturday, December 31, 2011 5:43:06 PM
Subject: Peculiar SNL behaviour

Last question for 2011 from me - I promise!

I have a sequence program with a couple of state sets running. To enable a state transition in one state-set, I set (or reset) a variable (which does not correspond to an EPICS PV) - see example below. here is my issue: I cannot seem to get the 'wait' state in stateset 2 to fire off without toggling 'pv1'.  

Here's what I do: assuming the PV  'epics:pv1C' is set to a BO record, I run the IOC. I see the console messages for the state sets firing off. I then set the VAL of 'epics:pv1C' to '1' and see that the ioc console responds with "PV Change state". After 2 seconds delay the internal variable 'seqFlag' is set to true, which _should_ (at least I think) fire off the 'wait' state in the second set, thus printing "Wait State Reached" on the IOC console. It does not. I have to set the PV 'epics:pv1C' to '0' and back to '1' to get the state transition to fire.

I don't think this behavior is appropriate - what say the community?

Contrived example:

/* epics variables */
short pv1; assign pv1 to "epics:pv1C"; monitor pv1;
/* sequencer variables */
short seqFlag = FALSE;

ss set1 {
 state init {
  entry {
   printf("Set 1 started\n");
  }
  when (pv1 == TRUE);{
   printf("PV Change state\n");
   } state seqHold
  }

 state seqHold {
  when(delay(2)) {
   seqFlag = TRUE;
  } state done

 state done {
  when(FALSE) {
  } state init
 }
}

ss set2 {
 state init {
  when(Delay(1){
   printf("Set 2 started\n");
  } state wait
 }

 state wait {
 when ((pv1 == TRUE) && (seqFlag == TRUE)) {
   printf("'Wait state' reached\n");
  } state done

 state done {
  when(FALSE) {
  } state init
 }
}

-- 
Tim Mooney ([email protected]) (630)252-5417
Software Services Group (www.aps.anl.gov)
Advanced Photon Source, Argonne National Lab

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System