Re: [foxboro] Cascade Master Block Reversing Control

I doubt TAC could reproduce your problem, unless you make it happen with =
a
simulation or provide some very specific test data.  Basically the =
BCALCI
incorporates the FBK and the INITO functions in one connection and are
redundant.  I would try to capture the deviation between the =
MASTERBLOCK.OUT
and the MASTERBLOCK.BCALCI as this is the integration input for the =
Integral
action.  Additionally, I would verify that neither the master or the =
slave
.INITI bits are true.   One other thing to check is the derivative.  If =
the
MASTERBLOCK.MEAS is oscillating unsymmetrically (high frequency =
saw-tooth
for example), it might be possible that the derivative function is =
driving
the controller output.  You might set the Derivative to 0.0 during such =
an
event to see if it stops.  Also the derivative has a Kd filter that can =
be
adjusted in case you are picking up some noise somehow.  Not sure why =
you
have PRIBLK=3D1 for the MASTERBLOCK?  I think this should be =3D 0.  I =
assume
that neither the Master of Slave loops are limited in any way during =
this
behavior.

=20
Rick Rys P.E.
www.R2Controls.com
508-369-5186 Cell
508-339-6633 Home Office
=20



 
 
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