Data Sheet

Type 3285
10 | 14
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6. Product operation
Standardon/ovalve
In the ON / OFF version, an external voltage signal is digitized and the valve is closed or opened. The status of the two end positions
of the valve are indicated on the LED. In addition, the valve position “closed” is reached via the digital output.
Standard control valve
The standard proportional valve converts an external standard signal (position set-point value) into a valve position. Both valve
end positions are indicated by the LED status. Additionally, the digital output indicates when the “closed” valve position has been
achieved.
Process diagram Description
Valve opening
Electromotive
actuator
Position measuring
system
Position
controller
Position
setpoint
value
CMD Xd1
CTRL
POS
Z1
POS
Position control
circuit
+
-
Valve body
Positioner version
The positioner proportional valve converts an external standard
signal (position set-point value) into a valve position. The position
of the actuator is controlled according to the position set-point
value. The current position (POS) of the electromotive valve is re-
corded by the position measuring system. The position controller
compares this position actual value to the set-point value (CMD)
specied as the standard signal. In case of a control dierence
(Xd1), the motor control signal is sent to the actuating drive as the
actuating variable. Z1 is a disturbance value.
Both valve end positions are indicated by the LED status. Moreo-
ver, the position actual value recorded using the position measur-
ing system is output via the M12 circular plug-in connector.
Process
controller
Position
control
circuit
-
SP
CMD
Z2
PV
Process variable
+
Xd2
-
Transmitter
Process
Process set-
point value
Vale
opening
Process controller version
The additionally implemented PID controller can perform not
only the actual position control but also a process control in the
sense of a cascade control. The process controller is integrated
in a control circuit. The position set-point value of the valve is cal-
culated from the process set-point value and the process actual
value using the control parameters (PID controller). The process
set-point value can be specied by an external signal. During the
process control the position control mentioned above becomes
the subordinate auxiliary control circuit; this results in a cascade
control. The process controller in the main control circuit has a
PID function.
The process set-point value (SP) is specied as a set-point value
and is compared with the actual value (PV) of the process variable
to be controlled. The position measuring system records the
current position (POS) of the electromotive linear actuator. This
position actual value is compared by the position controller with
the set-point value (CMD) specied by the process controller. If
there is a control dierence (Xd2), the actual position (POS) and
therefore the valve opening are changed by the control variable
(CTRL). Z2 represents a disturbance variable.