Page 52 - Practical Control Engineering a Guide for Engineers, Managers, and Practitioners

lntroductiou to Developing Control Algorithms l1

FIGURE 2-8 The diamond road map icon.

team can basically obviate the need for the activities in the "control
development comer."
However, should an algorithm be developed and installed, one
would move on to the top of the diamond and study the controlled
process in the time domain. Having done this, one could continue
around the diamond gaining insight and solving problems. For mne-
monic purposes the diamond is symbolized in Fig. 2-6.

2-3 Dealing with Control Algorithms
Bundled with the Process
What if you are selling a product such as an optical amplifier and you
want to augment your product with a controller that will, say, main-
tain a desired optical output power? Now, you are bundling the pro-
cess to be controlled with the controller and forming a product that
contains two components. This is quite a different situation compared
to that covered in Sec. 2-2.
What Is the Problem?
The product now has two components that can have problems: the
process and the controller. If the product is constructed so that only
the final output, say the optical power in the case of an optical ampli-
fier, can be monitored then how do you diagnose problems? Is it the
process or is it the controller?

Separation and Success
The key to success lies in designing the product with ports that
will allow the problem solver to tap into internal signals, namely
the controller input and the controller output. With these sig-
nals available, the problem solver can isolate the controller from
the process.