Hanna Instruments HI 8001, Инструкция по эксплуатации

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6.2 PID TUNING PROCEDURE
For the PID controller, we have three working modes:
1. With PID regulation algorithm (Proportional, Integrative and Derivative);
2. With Proportional regulation algorithm;
3. AUTO TUNING mode.
We will have one of the previous working modes as follows:
1. Having all the three components (Proportional, Integrative and Derivative),
the PID regulation algorithm has the best precision. This has the disadvantage of
requiring a most difficult tuning procedure especially for untrained personnel.
2. The Proportional regulation algorithm is very simple in implementation and
also in tuning procedure, but the working mode is not so good. It is used mainly
in systems where the dead time (the time from the on command to the response
of the system) is very small. This has the disadvantage that for non errors (the
measurement value in system reaches the reference value), the output command
is null.
Thus, in order to have an output command it is firstly necessary for the system to
produce an error (measurement value is different form the reference value), which
will have the effect of producing an output command in sense of minimizing that
error.
3. Auto Tuning algorithm is an algorithm that makes his own adjustment for the
output value. It has the advantage that the user is not involved in the tuning
process. From the accuracy point of view, this algorithm is situated between the
PID (well tuned) and Proportional regulators.
In the following sections we present the tuning methods for the first two types of
controllers (PID and Proportional), the third (AUTO TUNING) not involving the
user in the tuning process.
K T
I
T
d
REGULATION TYPE
> 0 < 99.9 > 0 PID
> 0 99.9 0 P
ROPORTIONAL
0
ANY VALUE ANY VALUE
AUTO
T
UNING
(
DEFAULT
)