... Operation and control In many processes, a physical variable such as temperature, pressure or voltage has to take up a specified value, and maintain it as accurately as possible A simple example is a ... numerical values, and uses them to calculate the manipulating variable This has certain advantages compared with analog processing: - increased accuracy of control, depending on the measurement ... already discussed in Chapter 1.3, “Operation and control , a parameter can be kept constant by suitable operation An example could be to maintain a constant furnace temperature Assuming a constant...