The next step was to develop the basic control philosophy.
This will include items like set point, hi and lo limits, kind
of exceptions reporting, etc.; also, at the same time, the
types of reports to be generated were also being defined.
These were broken down into two categories, the periodic
management reports and the process-variable messages. It
was decided to print the latter based upon management
by exception philosophy, i.e., a message will only be typed
when an out-of-limit condition was detected or when a
change was made.