Response sluggish

As the number of capacities in series increases, the delay in the initial response (sluggishness) becomes more pronounced. 

Now, from the discussion in Section 19.1 we are well aware of the undesirable consequences that dead time can have on the closed-loop response sluggishness or, even worse, destabilization of the closed-loop response. Therefore, the sampling period should be selected in such a way that the response of a process does not deteriorate. 

Fouling of the pH sensor may occur in solutions containing surface-active constituents that coat the electrode surface and may result in sluggish response and drift of the pH reading. Prolonged measurements in blood, sludges, and various industrial process materials and wastes can cause such drift. Therefore, it is necessary to clean the membrane mechanically or chemically at intervals that are consistent with the magnitude of the effect and the precision of the results requited. 

Time-Delay Compensation Time delays are a common occurrence in the process industries because of the presence of recycle loops, fluid-flow distance lags, and dead time in composition measurements resulting from use of chromatographic analysis. The presence of a time delay in a process severely hmits the performance of a conventional PID control system, reducing the stability margin of the closed-loop control system. Consequently, the controller gain must be reduced below that which could be used for a process without delay. Thus, the response of the closed-loop system will be sluggish compared to that of the system with no time delay. 

It has a disadvantage in that it may have a sluggish response to the control circuit demands due to its high time constant (r= L/R)... 

Any variable or parameter that influences kinetics can be used if well-defined perturbation can be achieved. Temperature was the early favorite in kinetic studies, but in catalysis the heat capacity of the catalyst makes the response for temperature changes very sluggish. A sudden change in one or more of the product or reactant concentrations can be executed faster and usually gives a better response signal. 

The differential-mode filter should have a lower damping factor than the common-mode because the combined damping response of the entire filter section would be too sluggish if higher damping factors were used. A damping factor of a minimum of 0.5 is acceptable. 

When Max Planck wrote his remarkable paper of 1901, and introduced what Stehle (1994) calls his time bomb of an equation, e = / v , it took a number of years before anyone seriously paid attention to the revolutionary concept of the quantisation of energy the response was as sluggish as that, a few years later, whieh greeted X-ray diffraction from crystals. It was not until Einstein, in 1905, used Planck s concepts to interpret the photoelectric effect (the work for which Einstein was actually awarded his Nobel Prize) that physicists began to sit up and take notice. Niels Bohr s thesis of 1911 which introduced the concept of the quantisation of electronic energy levels in the free atom, though in a purely empirical manner, did not consider the behaviour of atoms assembled in solids. 

When the pole p is negative, the decay in time of the entire response will be slower (with respect to only one single pole) because of the terms involving time in the bracket. This is the reason why we say that the response of models with repeated roots (e g., tanks-in-series later in Section 3.4) tends to be slower or "sluggish."... 

Repeated roots (of multi-capacity processes) lead to sluggish response. Tanks-in-series is a good example in this respect. 

In this example, the steady state gain is unity, which is intuitively obvious. If we change the color of the inlet with a food dye, all the mixed tanks will have the same color eventually. In addition, the more tanks we have in a series, the longer we have to wait until the -th tank "sees" the changes that we have made in the first one. We say that the more tanks in the series, the more sluggish is the response of the overall process. Processes that are products of first order functions are also called multicapacity processes. 

Example 3.3. Make use of Eq. (3-37), show how the unit step response Cn(t) becomes more sluggish as n increases from 1 to 5. 

Some texts use the term "sluggish" here without further qualification. The sluggishness in this case refers to the long settling time, not the initial response. 

Heat transfer lags can be significant and the nature of the problem can be quite different in various processes. If there is a sensor lag, it is mostly due to heat transfer between the sensor and the fluid medium. (Thermocouples, depending on how we make them, can have very fast response times.) The overall response is sluggish and PI control will make it more so. It is unlikely we can live with any offsets. PID control is the appropriate choice. 

In terms of the situation, if we use a PI controller on a slow multi-capacity process, the resulting system response will be even more sluggish. We should use PID control to increase the speed of the closed-loop response (being able to use a higher proportional gain) while maintaining stability and robustness. This comment applies to other cases such as temperature control as well. 

Problems with reference electrode/electrolyte. The sample solution can react with the electrolyte. The greatest source of error in biological solutions is through the formation of insoluble silver sulfide, often at the ceramic frit. A blackened spot is usually observed in a pH electrode that has been in service for a few weeks. This precipitate can impede the free flow of electrolyte and cause the probe response to become sluggish and cause large errors in the measured pH. 

Make a small setpoint or load change and observe the response of the con trolled variable. The gain is low so the response will be sluggish,... 

When a set point change from 0.986 to 0.99 for the heavy component (C) was considered, the responses shown in Figure 5 were obtained. The three options show good d mamic responses, with relatively low values of settling times, lower than 0.1 hours. The systems with unidirectional flows show some overshooting, while the Petlyuk system offers a more sluggish response. 

Adipose tissue, fat, is usually thought of as a metabolically sluggish energy reservoir and mechanical and thermal insnlator. It has proved to be much more than that. Adipose tissue influences the body weight, the inunnne response, the control of blood pressure, hemostasis, bone mass, and the fnnctions of thyroid and reproductive glands. It does these things largely on the basis of synthesis and release of a family of adipocyte peptide hormones. 

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