Setting Point Determination

Less Less Flow Excess ammonia in reactor. Release to work area, with amount released related to quantitative reduction in supply. Team member to calculate toxicity vs. flow reduction. 1. Valve A partially closed. 2. Partial plug or leak in pipe. Automatic closure of valve B on reduced flow from phosphoric acid supply. Set point determined by toxicity vs. flow calculation. 

If very close control is desired, then any disturbance due to steam pressure changes should be minimized. Figure 7-9 shows how this can be done using a cascade control system. In this case, the temperature of the process stream is measured and compared to its desired value, as before. The output of the controller, however, instead of affecting the control valve, regulates the set point of a second controller, the steam-pressure controller. This controller compares the set point determined by the first controller with the pressure downstream of the steam valve. 

Keesey RE, Hirvonen MD. Body weight set-points determination and adjustment. J Nutr 1997 127 1875S-1883S. Keesey RE, Mitchel JS, Kemnitz JW. Body weight and body composition of male rats following hypotha-... 

A volume of wine is pumped into the treatment vat and then into the diluate circuit of the electrodialysis cells. When conductivity reaches the set point, determined by an instability test, the wine is automatically pumped into a reception vat using a system controlled by solenoid valves. A new volume of wine is then pumped into the system and stabilized under the same conditions. Treatment time and, consequently, the performance of the system depend on the wine s degree of instability. Treatment flow rates vary from 50 to 150 1/h/m, depending on this parameter. The concentrate circuit consists of a saline solution that collects the ions extracted from the wine. The ion load is adjusted by adding water to avoid the precipitation of bitartrate crystals inside the small, easily blocked cells. This function is also automatically controlled by conductivity measurements. 

T is the jacket temperature set point determined by the primary controller. Recall the observer-based inverse dynamics (Eq. 41), drop its dynamics component (Eq. 41a), replace Tj by Tj, assume that xi is known, and obtain the observer (43a) plus the nonlinear state feedback controller (43b) ... 

Repeat starting from step 1 for two new potential controlled variables and/or different set points. Determine which combination of controlled variables produces the best overall control performance for all the feed variances by finding the pair with corresponding set points that meet the control objectives for all variances tested. 

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