allan kern, p. e. owner and president, apc performance,...
TRANSCRIPT
Allan Kern, P. E. Owner and President, APC Performance, LLC
Preamble
Grew out of 10+ year effort to improve, not replace, model-based control
A natural continuation of that work, for the benefit of industry
Today’s presentation is “selected APC topics” ╸Technical presentation/information available online
Thesis is an impending update to APC 1.0 paradigm
Slide 2
APC 2.0 Presentation contents
Built-in DCS functionality (think function blocks) Emphasis on basic process control (not opt.) Matrix is the core concept (not model-based control) Automated modeling will not resolve MPC issues ╸just as auto-tuning was unable to resolve PID
Model-less control theory: RPC® Rate-Predictive Control (single-loop) ╸Inherently adaptive (think “naturally self-tuning”) ╸This has always been the grail of process control
XMC® Model-less matrix control (multivariable) ╸“Pre-certified” – automates traditional (pre-computer)
industrial process operation methods
Slide 3
Built-in / Agile / “Operational” APC 2.0 Solution
Native (built into) DCS (think function blocks) Owned by site process control engineers ╸And applied by site operating team
No ongoing cost or maintenance req’ments Intuitive to operators (not complex/confusing) No barriers (time/cost/resource) Scalable, agile, operational, etc. (flexible tool) Core competency of process industries Organic vs. monolithic paradigm Compare to evolution of similar technology: ╸Alarm Management and GPS
Slide 4
Behold the matrix!
Slide 5
The most important and (ultimately) enduring contribution to APC from the model-based era ╸not “model-based control”
Defines the constraint management and optimization scenario of essentially every industrial process
The “same page” for control engineers, process engineers, operations team, and RTO
ICV 1 2 3 4 5 6
51AI110 51AI115 51AI116 51AI125 51PC105 51PDI104
DCV NAP90 KERO90 KEROFLSH DSL90 PRESSURE TOP DP
1 51TC102 HEATER +1
2 51FC103 STEAM +1
3 51FC128 PUMP-AR -1 -1
4 51TC106 TOP TEMP +1 +1 +1 +1
5 51FC112 KERO DRAW +1 +1
6 51FC122 DIESEL DRAW +1
7 51HC128A PA BYPASS +1 +1
Optimization pyramid:
Planning Level (RTO) ╸Planning, process engr., maintenance ╸Site or enterprise wide (no horizon limit)
Operating Level ╸Chain of command, field operators,
console operators, business tools, etc.
Control System Level ╸Goal is to close loops ╸Manage dynamic constraints / matrix ╸Optimization is misplaced focus at this
level
Slide 6
Local
Global
Automation horizon
Op. Team horizon
Automated remodeling is the latest (but not last) attempt to overcome structural limitations
Models change ╸short-lived, often dynamic, anything but durable
Model-based performance is not appropriate in most applications
Vastly over-engineered solution ╸Large matrix vs. small matrix design practice ╸Embedded optimizer vs. configured objectives
“Aha” (structural issues): ╸PID and MPC have followed same trajectory!
Slide 7
Rate-Predictive Control (RPC®) (Patented)
Inherently adaptive to changes in process gain
Preset move rate
SP or Target change
and to changes in move size
RPC®
Slide 8
XMC® Model-less multivariable control method
5-Second Period
1. Based on gain directions, constraints and targets
Automates traditional proven operating methods Reliably captures multivariable control value
2. Based on experience, procedures & knowledge
3. Novel method to taper moves predictively
Directional Move-Solver
Pre-Selected Move Rates
Rate-Predictive Control (RPC®)
Slide 9
Value in solving a demanding problem in a simple way
As simple as possible, but not simpler Build a better mouse trap Everyone got a microwave, but nobody got rid of
their oven
Slide 10
Model-less:
Model-based:
Who will benefit from model-less control?
Control and Process Engineers ╸A more agile and accessible tool to meet everyday
challenges
Supervisors and Managers ╸A more cost-effective and manageable alternative
Advanced process control community ╸Compelling theoretical foundation and practical
basis
Control system manufacturers ╸Add value by building model-less technology into
product offerings
Slide 11
Conclusions
Industry is in a position to re-evaluate the PID and MPC paradigms, now with viable alternatives for comparison
Due to structural limitations, model-based technology will continue to underserve industry as an operational technology
Model-less technology is breakthrough technology, both single-loop and multivariable, with notable industry firsts
Inherently adaptive control is the grail of process control, and multivariable control is an essential core-competency
Model-less technology would be competitive in any environment, today it should be especially welcome!
Slide 12
