Burkert Type 8793 - Manual (Page 19)

19
Description of System
8. POSITIONER TYPE 8792
The position sensor records the current position ( POS) of the pneumatic actuator. The positioner compares this
actual position value with the set-point value ( CMD) which is specified as a standard signal. If there is a control dif-
ference (Xd1), the actuator is aerated and deaerated via the control system. 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 sensor
Positioner Position set-
point value
CMD Xd1
B1
E1
P
K
Z1
POS
Position control circuit
+ -
Figure 3: Position control circuit in Type 8792
8.1. Positioner (position controller) Type 8793 Remote
with external position sensor
In the case of this model, Type 8793 has no position sensor in the form of a rotary position sensor, but an external
path sensor.
By connecting the path sensor to the analog interface (4... 20 mA), Type 8793 can be operated only as a
positioner (position controller).
The options for connection of a path sensor are described in Chapter “12.4. Remote operation with
external position sensor”.
English
Types 8792, 8793