Re: [foxboro] system error in sequences
- From: Gabriel ODwyer <ODWYER_GABRIEL@xxxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Wed, 25 Aug 2010 10:58:37 +0100
Hi Dirk, we have a rule of thumb here that says we put in a WAIT statement
(WAIT 0.1 for example) after every three reads/writes to a C:B.P, the
reason we do this has its origins way back in AP10 time, but we noticed
that, sometimes, if we set more than 3 C:B.P's at a time then some of the
writes beyond three would be missed. Also, we tend to create labels where
possible, i.e. your PRESS_CP4:PT_HOPPER.PNT would be connected to, say,
RI0001 of the sequence block and labeled in the code something like:
HOPPR1_PRESS : RI0001; {Hopper number 1 pressure}.
The reason I say this is because you may, at times, be hitting a situation
where your REPEAT is spinning around too fast and missing reads
occasionally.
We also use the retry facility in our exception handlers with no problems,
usually like this:
{** SYS ERROR SUBROUTINE **}
BLOCK_EXCEPTION
TO_SYS_ERROR
STATEMENTS
IF OP_ERR < 3000 THEN
IF RTYCNT <= 2 THEN
RTYCNT := RTYCNT + 1;
RETRY;
ENDIF;
ENDIF;
SENDMSG ("SYS ERROR = ",OP_ERR," B_STMNO = ",BLOCK_STMNO) TO MSGGR1;
ALSTNG := "SYS ERROR";
CALL SHUTDOWN ();
CALL ALARM ();
CALL HOLD ();
ENDEXCEPTION
Regards,
Gabriel.
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