Siemens SIPART DR21

1 General Part -- Fundamental control technology termsManual
SIPART DR21
C73000-B7476-C143-08
13
Kp Proportional gain
Tn Integral action time
xd System deviation
Δy Manipulated variable of controller
y Manipulated variable of motor
Tn
Kp · xd
y
Δy
t
t
Figure 1-8 Transient function and parameters of the three-position step controller
D Continuous controller
The controller output 0 to 20 mA or 4 to 20 mA acts on the final control element via an
electropneumatic signal converter or an electropneumatic positioner.
2
w
xd
3
1
x
y
-
4
0to20mA
(4 to 20 mA)
0.2 to 1 bar
w Command variable
x Controlled variable
xd System deviation
y Manipulated variable
1 Transmitter
2 Stepoint adjuster
3 Control amplifier
4 Electropneumatic signal
converter
5 Pneumatic actuator
Figure 1-9 Function diagram of continuous controller
This type of controller is preferentially used in the chemical industry.