Understanding What Process Control Is

Although it may seem strange, there are certain forms of process control that we execute on a daily basis. Suppose you are taking a shower, in which the flow rate of hot water is fixed, and we can adjust the flow rate of cold water to achieve a pleasant water temperature. Most likely, you would proceed as follows  

Through our skin we are continuously sensing (feeling) the temperature of the water. 

(a) If the water is warmer than we expect, then we will increase the flow rate of cold water, (b) If the water is colder than we expect, then we will reduce the flow rate of cold water. 

After changing the flow rate of cold water, given that the skin is constantly sensing water temperature (step 1), then depending on the outcome, we will return to step 2(a) or (b) until we feel a pleasant water temperature. 

Using this everyday example, we can identify several elements that constitute a controlled process as follows. 

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