Re: [foxboro] system error in sequences
- From: dirk.pauwels@xxxxxxxxxx
- To: foxboro@xxxxxxxxxxxxx
- Date: Mon, 30 Aug 2010 10:02:31 +0200
Hi Chuck,
Thanks for the advice, For these (small) sequences I already changed the
code using user labels, but I have many sequences where there are too many
C:B.P references to use user labels, I'll go through the sequences and
change the network calls using variables where needed.
Rgds,
Dirk
"Jones, Charles R. (Chuck)" <Chuck.Jones@xxxxxxxxxxxxxxx>
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27/08/2010 12:30
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Re: [foxboro] system error in sequences
Dirk,
I have another suggestion (or maybe just a style point). I try not to
put more than one network call into a single line of code. For example:
IF (:PRESS_CP4:PT_HOPPERR1.PNT -
:LOGIC_PRESS:R1_PRESS.RO01) <
RI0002 AND :PRESS_CP4:PT_HOPPERR1.PNT < 5 THEN
In that line there are three calls to the network for information (one
is called twice). Each call causes the current sequence to wait for at
least one BPC of the sequence block. If one of the calls fails, how
will you know which is the problem? The sequence block error message
will only give you the line number in the sequence.
Another way to write the same code would be to use some new variables:
HOPPERR1 := :PRESS_CP4:PT_HOPPERR1.PNT;
R1_PRESS := :LOGIC_PRESS:R1_PRESS.RO01;
DeltaPress := HOPPERR1 - R1_PRESS;
IF (DeltaPress < RI0002) AND (HOPPERR1 < 5.0) THEN
It may only be a style point, but I have had fewer problems since I
started breaking things up.
Chuck Jones
Automation Technologist
Tate & Lyle Lafayette Plant
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