Friday is a Meet the Experts day at Emerson Exchange where a multitude of panels are assembled to field questions from the user community.
I’m in the “Expanding the Use of DeltaV Advanced Control” panel with a great line up of advanced control technologists and practitioners. The panel includes Emerson’s Terry Blevins, Will Wojsznis, and Lou Heavner, Spartan Control’s Terry Chmelyk, and Weyerhaeuser’s Chris McNabb.
The panel opened introducing themselves with their combined experience approaching two centuries. Terry Chmelyk then came up to discuss using the model predictive controller, DeltaV PredictPro on top of control systems from other automation suppliers.
While embedded advanced control in the DeltaV system has tremendous advantages in integrated performance, it can also provide benefits when combined with other control systems. MPC can simplify control problems in many cases because it can address interacting loops very well.
The architecture to connect DeltaV advanced control to other systems is connect have the MPC modules at top to connect to emulation modules. These emulation modules connect to landing modules to provide bi-directional reads and writes to the interface layer with the other control system. The interface is typically redundant virtual interface modules (VIMs), OPC, or Modbus.
Terry shared how the optimization in applications including pulp & paper lime kilns created energy savings that funded the control system modernization projects to move to the DeltaV system.
Chris came up to describe a pulp & paper bleaching project where chlorine dioxide is created at the mill. The process required a tremendous number of operator actions to optimize the process. The process had numerous flow controllers and analyzer to measure solution strength. When the DeltaV MPC controller was applied, all of the required manual adjustments were for the most part eliminated.
Lou came up next to share a story of integrating with other control systems. Slower execution rate applications on the order of 5 seconds or greater are ideal for the MPC interfaced with non-DeltaV control systems. It’s important to get the mode-switching and watchdog timer logic in place. He shared some specific applications and tricks to work with compressor controllers, gas chromatographs, and other very-specific equipment.
Terry Blevins came up to describe the use of inputs from wireless devices. With the PIDPlus block in the DeltaV system, the algorithm handled the non-periodic updates.