Siemens SIMATIC S5-115U, Руководство пользователя

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S5-115U Manual Integral Blocks
Figure 11-4. Estimating the Dominant System Time Constant (T
RKdom
)
x
d
t
x
x = Controlled variable
t = Time
T
A
= Sampling time
T
RKdom
= Dominant system time
constant
w = Reference
variable/setpoint
x
d
= System error
w
a a a a
a a a a
a a a a
a a a a
a a a a
T
A
T
RKdom
Example for the Use of the PID Control Algorithm
Using a PID controller to keep an annealing furnace at a constant temperature.
The temperature setpoint is entered via a potentiometer.
The setpoints and actual values are acquired using an analog input module and forwarded to the
controller. The computed manipulated variable is then output via an analog output module.
The controller mode is set in input byte 0 (see control word DW 11 in the controller DB).
You must use the well-known controller design procedure to determine how to tune the con-
troller for each controlled system.
EWA 4NEB 811 6130-02b
11-39