Allan Kern

Allan Kern, P.E., is Principal APC Consultant with Lin & Associates, Inc., of Phoenix, Arizona. He is the inventor of patented Rate-Predictive Control (RPC) and Model-less Multivariable Control (XMC).

latest from Allan Kern

PID, APC

Understanding the role of multivariable control in industrial process operations

Courtesy: Control Engineering webcast, Advanced process control: Past, present and future.

PID, APC

Advanced process control: More answers

Figure 1: Multivariable control matrix for an atmospheric crude distillation column, based on operation-driven design practice. The matrix is smaller than traditional crude column applications. It addresses primarily column pressure and product inferential quality control, which are often the most valuable objectives of this application – and often the ones found “unclamped” in existing large-matrix applications. Courtesy: APC Performance LLC

PID, APC

Operation-driven matrix design

Figure: Rate-predictive control (RPC) is inherently adaptive (think naturally self-tuning) to changes in process gain. In the top graph, process gain is 1.0, while in the bottom graph, process gain is 2.0. Control performance remains “perfect,” with no change to RPC tuning parameters. Courtesy: APC Performance LLC

PID, APC

Advantages of RPC and limits of model-based control

Figure 3: An alarm priority matrix shows potential the severity of consequences versus time-to-respond. Courtesy: APC Performance

Process Safety

10 alarm management tips for the busy control engineer

Model-less multivariable control (XMC) automates the way operating teams have always carried out multivariable constraint control and optimizaton manually. Notably, this method does not require detailed models or embedded optimizers. XMC uses patented rate-predictive control (RPC) internally. Courtesy: APC Performance LLC

Process Instrumentation and Sensors

Model-less multivariable control benefits

Figure: Rate-predictive control (RPC) uses a pre-set move rate, and tapers the move based on the PV’s predicted (apparent or already manifest) value. The U.S. Patent and Trademark Office (USPTO) has hundreds of patents for process control; as of this writing, RPC is the only one with the claim of being inherently adaptive. Courtesy: APC Performance LLC

Process Instrumentation and Sensors

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