User manual - CONTROLLER PUR-94
Fuzzy logic block (FuZL submenu)
Step changes in the setpoint can be mitigated by the use of the fuzzy logic block, which
inserts speed control of the setpoint change. Thanks to its application the user may dictate
how quickly a fuzzy value approximates the target value in the process (
SEtP
).
This feature is particularly useful in systems where too rapid change in the setpoint and,
as it is possible in such a situation, the control signal, could lead to unwanted behaviour on the
part of a object, for instance destruction of the product being manufactured. It is also possible
to set the minimum difference between the setpoint (
SEtP
), and the fuzzy setpoint, beyond
which the controller step changes the fuzzy setpoint to the setpoint (
SEtP
). This is defined by
the
HYST
parameter. Both controllers use the same settings of the fuzzy logic block.
Figure 6.7. Comparison of the PID-H controller’s response to a change in the setpoint using
and without the use of fuzzy logic
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PID-H controll loop
FuZL on
FuZL off
time
se
tp
oi
nt
Histeresis
