Products: Controller trouble-shooting software on site or long distance

By Control Engineering Staff February 7, 2007

The TOPAS process control toolset from ACT is available for purchase outright or through a service arrangement with the company for assistance with difficult situations via long distance. In one situation, ACT’s managing director, Hans Eder, recounted that a customer sent process parameters for a unit that had a swinging controller which would not settle down. ACT loaded the information into its software and calculated settings that stabilized the process in only 10 minutes.

TOPAS reportedly uses more than 20 tuning methods, evaluates them specifically for the given situation, and selects the best results. Besides a proprietary method, highly recognized formulas like Astrom, Cohen-Coon, Chien-Hrones-Reswick, IMC, ITAE, etc. have been included, some adapted. Tuning is calculated specifically for setpoint changes or load upsets and users can opt for best performance, smoothest control action, or minimum consumption of the resource. For the three best results, the loop behavior is presented graphically. Further testing and quick refining such as for the effect of noise, sticking valves, process non-linearity, or changes in the dynamics can be carried out with the integrated simulation environment.

For easy and fast estimation of process parameters, TOPAS provides several methods, from a step or relay test or operating data, even from a closed loop test (no oscillation required). Furthermore, general formulas for integrating processes have been added to the ones for tight and average (error squared) liquid level control.

— Control Engineering Daily Daily News Desk Peter Welander , process industries editor