Using Pi Control - Omron I537-E2-01 User Manual

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Using PI Control

PI control is a method of making the feedback value (detection value) match the set target value. By combin-
ing proportional control (P) and integral control (I), you can even control targets (machinery) with play time.
The characteristics of the PI control operations are given below.
P control Outputs the amount of operation proportional to the deviation. You cannot, however, set the
deviation to zero using P control alone.
I control Outputs the amount of operation that integrates the deviation. Used for matching feedback
value to the target value.
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PI Control Operation
To understand the differences between the PI control operations P and I, the variation in the amount of opera-
tion (output frequency) is as shown in the following diagram when the deviation (i.e., the difference between
the target value and feedback value) is fixed.
Deviation
Amount of operation
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PI Control Applications
The following table shows examples of PI control applications using the Inverter.
Applica-
tion
• Feeds back machinery speed information and matches speed to the target value.
Speed Con-
• Inputs speed information from other machinery as the target value and performs
trol
synchronous control using the actual speed feedback.
Pressure
Feeds back pressure information and performs parameter pressure control.
Control
Flow Rate
Feeds back flow rate information and controls the flow rate highly accurately.
Control
Tempera-
Feeds back temperature information and performs temperature adjustment control by
ture Con-
rotating the fan.
trol
Fig 6.42 PI Control Operation
Control Details
Individual Functions
Time
P I con trol
I control
P control
Time
Example of
Sensor Used
Tachometer genera-
tor
Pressure sensor
Flow rate sensor
• Thermocouple
• Thermistor
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