INFICON Composer Gas Concentration Controller - Manual (Page 90)

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Composer Operating Manual
Figure 3-12 Linear regression fit of data points taken in Figure 3-11 . In this particular process,
the time constant and dead time are 33.5 sec and 9.1 sec respectively.
3.2.3 How to Determine Process Parameters
Whether one uses the PID controller or the Fuzzy Logic controller, knowledge
of the process to be controlled is essential, because the control parameters are
ultimately derived from process parameters. The process parameters can be
effectively determined by using either the Composer Setup Tool software, or the
Monitor software, or the Composer’s system I/O interface, or the front panel
keypad (for unit with LCD display). The following sub-sections describe
step-by-step the procedure for deriving these parameters using each of the
aforementioned interfaces. The values determined in this manner are not
precise, but result in adequate functioning of the control loop. A more precise
method for determining process parameters has been elaborated in
section
3.2.2, How to Precisely Tune a Control Loop, on page 3-25 .