Thermometer step response

Figure 3.22 shows, in bloek diagram form, the transfer funetions for a resistanee thermometer and a valve eonneeted together. The input X[ t) is temperature and the output Xo t) is valve position. Find an expression for the unit step response funetion when there are zero initial eonditions. 

The step response for Example 3.8, the resistanee thermometer and valve, shown in Figure 3.23 ean be generated with seript file examp38.m. 

The ideal (bio)chemical sensor should operate reversibly and respond like a physical sensor (e.g. a thermometer), i.e. it should be responsive to both high and low analyte concentrations and provide a nil response in its absence. One typical example is the pH electrode. In short, a reversible (bio)chemical sensor provides a response consistent with the actual variation in the analyte concentration in the sample and is not limited by any change or disruption in practical terms, responsiveness is inherent in reversibility. An irreversible-non-regenerable (bio)chemical sensor only responds to increases in the analyte concentration and can readily become saturated only those (bio)chemical sensors of this type intended for a single service (disposable or single-use sensors) are of practical interest. On the other hand, an irreversible-reusable sensor produces a response similar to that from an irreversible sensor but does not work in a continuous fashion as it requires two steps (measurement and renewal) to be rendered reusable. Figures 1.12 and 1.13 show the typical responses provided by this type of sensor. Note... 

Platinum resistance thermometers monitor the temperature, and a three-term tunable PID controller, which is RS232-linked to a PC, stabilizes the v ue at the set point to an accuracy of at least 0.1 °C by regulating the secondary heat transfer. The set point temperature can be prograimned, so that precise thermal cycling is available, or manually entered for step variation. The woridng temperature range is 5 C with a thermal response 0.2°C/s. 

Fig. 1.7. Thermometer response to a step ehange in environmental temperature.

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