User manual - CONTROLLER PUR-94
Figure 6.5. The general structure of the
Figure 6.6. General scheme of the PID controller implemented in the
device
Configuring the PID controller
The PID controller can be configured in two ways: manually and automatically.
In manual mode, the user defines all factors and additional elements of the controllers
(fuzzy logic, inertia, output limiting and dead zone) at their own discretion. The settings chosen
by the device in automatic mode can also be improved and fine-tuned. The user can disable
each block of the PID controller as well as additional blocks. This is done by setting the zero
value or
OFF
option in the selected parameter.
In automatic mode, in the auto-tuning process using the
Ziegler-Nichols
method, the
device calculates and tunes the parameters
P, I
and
D
of
one of the controller’s loops.
Additional blocks (fuzzy logic, inertia, output limiting and dead zone) are not configured in this
mode and the user must choose them himself according to respective applications. The auto-
tuning process is described later in this chapter.
23
FuZL
Setpoint
SEtP
inPt
Controlled
object
Measurement
input
Fuzzy logic block
Feedback
Fuzzy
setpoint
PID H
PID C
Modbus
Master
Sour
modE
Out.: rELx/OCx
OSou
Omod
Analogue
output
LooP
Err
1
P
-H
P
-C
t
I
-H
t
I
-C
t
d
-H
t
d
-C
dEAd
InEr
Dead zone
Proportional
block
Integral
block
Derivative
block
Inertial
block
Feedback
Output
limits
Setpoint
SEtP
or
Fuzzy
setpoint
Upper limit
Hi-H
Hi-C
Lower limit
Lo-H
Lo-C
Offset
OF-H
OF-C
