1 General Part -- Fundamental control technology terms
Manual
12
SIPART DR21
C73000-B7476-C143-08
D
Controller output signal
The controller ouptut signal must be adapted to the final control element. The following must
be used according to the type of drive/final control element:
Type of drive/actuator
Controller output signal
Electric actuators
Three-position step controllers
Pneumatic and hydraulic actuators
Continuous controllers
Direct heaters/coolers
Two-position controllers
D
Three-position step controller with internal feedback
The three-position step controller switches the electric motor of the actuator to clockwise,
stop or counterclockwise by means of relays or semiconductor switches. The rate of adjust-
ment of the actuator can be influenced using different switch-on/pause ratios.
w
Command variable
x
Controlled variable
xd System deviation
y
Manipulated variable
1
Transmitter
2
Stepoint adjuster
3
Three-position switch
4
Feedback with time
response
5
Control amplifier
6
Actuator
2
M
w
xd
5
3
4
L1
N
1
x
6
y
0 to 20mA
(4 to 20mA)
Figure 1-7 Function diagram of three-position step controller
The output response to the three-position amplifier in conjunction with the integral-action
actuator permits a “continuous” manipulated variable taking into account the response
threshold.
Summary of Contents for SIPART DR21
Page 1: ...SIPART DR21 C73000 B7476 C143 08 1 SIPART DR21 6DR 210 Edition 08 2010 Manual ...
Page 2: ...SIPART DR21 C73000 B7476 C143 08 2 ...
Page 148: ...4 Installation 4 2 Electrical Connection Manual 148 SIPART DR21 C73000 B7476 C143 08 ...
Page 180: ...5 Operation 5 5 CPU self diagnostics Manual 180 SIPART DR21 C73000 B7476 C143 08 ...
Page 242: ...Manual 242 SIPART DR21 C73000 B7476 C143 07 ...