Burkert Type 8624 - Manual (Page 35)

8624-2 Standard - 33
english
Example of an inverted control system
In the following system the actual value at the output of the unregulated pump is to
be controlled by changing the opening of the proportional valve in a return flow
loop. If the actual value is too high (x
d
<0), the correcting variable must be
increased (inverted control).
Fig.: Example of an inverted control system
Î Via this function you set the sense of action between the input signal and
the setpoint of the valve (factory setting: NO).
6.6.7 INV - inverted/non-inverted control
non-inverted control y = K
p
(x
d
+ T
A
/T
N
∑ ∑ ∑ ∑ ∑ x
d
)
inverted control y = - K
p
(x
d
+ T
A
/T
N
∑ ∑ ∑ ∑ ∑ x
d
)
non-inverted control ( NO):
Output signal y of the PI controller
increases with increasing positive
control difference x
d
= w-x.
inverted control ( YES):
Output signal Y of the PI controller
increases with increasing negative
control difference x
d
= w-x.
1
1
Fig.: inverted/non-inverted control
Working
resistance
Pump
Sensor
Proportional valve