Displaying 1–25 of 41 results for Cecil L. Smith, Cecil L. Smith, Inc
Most processes are multivariable, which means they need a control system with two or more loops. Sometimes, interaction among loops can render one or more of them untunable. Here are practical pointers on how to address such issues.
Understand the nuances for steam-heated exchangers
Professional development courses can give you an edge
Well-known authority presents a series focused on a multivariable application
Neglect Level Control at Your Peril -- This first article in a four-part series examines reset mode tuning issues.
Control Level with a Cascade -- This requires different thinking about master and slave loops.
Instrumentation: Consider Cascade Control -- Such configurations sometimes offer benefits for tubular exchangers.
Look at Liquid Bypass -- Such process-side control of tubular exchangers offers advantages.
Avoid Vessel Level Trips -- Nonlinear control equations provide important advantages.
Be Levelheaded About Surge-Tank Control -- Vessels used to smooth out flow pose special tuning issues.
Pump curves suggest rethinking the usual control strategy
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<p>One of our Ask the Experts panelists, Girish K. Malhotra, alerted me to ...
The critical variables are the scrubber duct inlet temperature and the bag house inlet temperature. Both must remain above the dew point at all times. This video examines how these two loops affect each other.
The temperature of the hot air is determined by the opening of the fuel gas valve and the opening of the fresh air damper. Based on the process understanding from previous videos, this video proposes alternate control logic for these two final control elements.
The loops proposed in the previous video complete the alternate control configuration. A previous video also examined tuning the feedback trim controller for the hot air temperature. This video will tune the other three loops. The first issue is the order for tuning the loops.
Short video highlights when blocks such as summers, selectors, etc., are inserted between the output of the PID block and the final control element, some configuration issues must be addressed for the PID block.
The subject of this video is commissioning the ratio configuration that uses the characterization function.
Should a hot air damper be driven either fully open or fully closed, integral tracking must be activated in either the hot air pressure controller or the bag house inlet temperature controller. The issues are similar to those for output tracking presented in a previous video.
This video proposes controls for the hot air pressure and the bag house inlet temperature. Interaction is a major concern. Opening either hot air damper decreases the hot air pressure. Opening the hot air damper to bag house inlet increases the bag house inlet temperature. Opening the hot air ...
For a PID controller to perform as expected, changes in the controller output must lead to changes in the opening of one or more final control elements, which must affect the measured variable for the PID controller. Driving a final control element to either limit disrupts this sequence. This ...
<p>This video examines the degree of interaction between the scrubber duct ...
<p>The off-gas process is an excellent example of a multivariable process ...
Previous videos examined output tracking for the scrubber duct inlet temperature controller and the hot air temperature controller. This video examines output tracking for the hot air pressure controller and the bag house inlet temperature controller.
This video examines output tracking for the hot air temperature controller. The hot air temperature controller outputs to a summer whose output is the fresh air damper opening.