SED 024.16.720 - Type 024.16.720 Positioner with Position Controller; Schematic Representation of the Position Control Type 024.16.720

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System Description
Type 024.16.720
6.5. Type 024.16.720 Positioner with position controller
The position measuring system records the current position (POS) of the pneumatic actuator. The position con-
trollercomparesthisactualpositionvaluewiththeset-pointvalue(CMD)whichisdenableasstandardsignal.In
case of a control deviation (Xd1), a pulse-width modulated voltage signal is sent to the control system as a manip-
ulated variable. If there is a positive control difference in single-acting actuators, the air inlet valve is controlled via
output B1. If the control difference is negative, the bleed valve is controlled via output E1. In this way the
position of the actuator is changed until control difference is 0. Z1 represents a disturbance variable.
Valve
opening
Control valve Control system
Solenoid valves
Position measuring system
Position
controller
Position
set-point
value
CMD Xd1
B1
E1
P
K
Z1
POS
Position control
circuit
+
-
Fig. 4: Signal ow plan of position controller
6.5.1. Schematic representation of the position control Type 024.16.720
4 ... 20 mA
1)
0 ... 20 mA
CHARACT
SPLTRNG
2)
DIR.CMD
CUTOFF
X.TIME
2)
X.CONTROL
DBND
POS
CMD
INP
POS
CMD
DIR.ACT
2)
X.LIMIT
2)
1)
Default setting
2)
can only be activated with communications software
Fig. 5: Schematic representation of position control