I.
Manual tuning
For manual tuning in online system one of the methods is first setting all gains to zero. Increase
the
value until the constant oscillation of the output is obtained and then
should be set
to approximately half of that value for a quarter amplitude decay type response. After that
increase
to minimize the P term offset in a particular time for the process considering that
too much
can be a cause of instability. Finally, increase
, if required, until the system
becomes acceptably quick to reach the Set Point and decrease the oscillation. However, too
much KD will lead to overshoot in the system. A quick PID controller loop normally has a little
overshoots to achieve the desired value very fast; but in some systems cannot receive
overshoot. In these systems a KP should be set remarkably less than half of the KP setting
which provoked oscillation, to make over-damped in the closed-loop system [9] [15].
Parameter
Rise Time
Overshoot
Settling
Time
Steady-State
Error
Stability
Increasing
Decrease
Increase
Small
Increase
Decrease
Decrease
Increasing
Small
Decrease
Increase
Increase
Large
Decrease
Decrease
Increasing
Small
Decrease
Decrease
Decrease
Minor Change Improve
Table 3. 1 Effects of independent P, I and D tuning on closed-loop response
II.
CONVENTIONAL PID TUNINGS TECHNIQUE
There are different tuning correlations used in conventional PID tunings technique among
those some of the methods are discussed below.
Fuzzy PID Based Temperature Control of Electric Furnace for Glass Tempering Process
M.Sc. Thesis, Addis Ababa University, December 2016
35
Do'stlaringiz bilan baham: |