Burkert Type 8693 - Manual (Page 20)

20
Description of system
7. Type 8692
pOsiTiOner WiTh pOsiTiOn cOnTrOller
The position measuring system records the current position ( POS) of the pneumatic actuator. The position controller
compares this actual position value with the set-point value ( CMD), which is definable as norm signal. In case of
a control deviation (Xd1), a pulse-width modulated voltage signal is sent to the control system as a manipulated
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
Continuous
valve Control system
solenoid valves
Position measuring
Positioner Position set-
point value
CMD Xd1
B1
E1
P
K
Z1
POS
position control circuit
+ -
Figure 4: Signal flow plan of position controller
english
Type 8692, 8693