My site has an MPC-Pro application for supplemental fuel minimization, for a fired heater that also has constraints on stack emissions.
Periodically, the stack emissions sampling system initiates a calibration or a blow-back, lasting about five minutes. A sample-and-hold is invoked for the variables, but this can cause issues if the "hold" is invoked during a higher excursion.
"MP Operate Pro" interface displays a "Disable" button for each variable - I would like to disable the stack variable constraints during these episodes. Anyone have an idea what variable / parameter in the MPC-Pro block I would toggle to accomplish this?
Thanks,
John
In reply to James Beall:
In reply to Lou Heavner:
Great info from Lou Heavner! Note that you can actually specify the Shed time in multiples of the Tss with the parameter "SIM_TIME_FACTOR". Be aware that there was a time period (Version 13.3 I think) where the the SIM_TIME_FACTOR parameter did not act as stated in BOL shown below. Check with DeltaV tech support on this issue. You could still use the parameter, you just had to adjust the value that you used to get the Shed time you desired.
In reply to John Rezabek: