B5: Pi Control - YASKAWA E1000 Technical Manual

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Timer Function Operation
When the timer function input closes for longer than the value set in b4-01, the timer output switches on. When the timer
function input is open for longer than the value set in b4-02, the timer output function switches off. The following
diagram demonstrates the timer function operation.
Figure 5.14
Multi-function Contact
Input: Timer Function
Multi-function Contact
Output: Timer Function

◆ b5: PI Control

The drive has a built in PI (Proportional + Integral) controller that can be used for closed loop control of system variables
such as pressure, temperature, and so on. The difference between the target and the feedback value (deviation) is fed into
the PI controller. The PI controller adjusts the drive output frequency in order to minimize the deviation, providing
accurate control of system variables.
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P Control
The output of P control is the product of the deviation and the P gain so that it follows the deviation directly and linearly.
With P control, only an offset between the target and feedback remains.
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I Control
The output of I control is the integral of the deviation. It minimizes the offset between target and feedback value that
typically remains when pure P control is used. The integral time (I time) constant determines how fast the offset is
eliminated.
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PI Operation
To better demonstrate how PI works, the diagram below shows how the PI output changes when the PI input (deviation)
jumps from 0 to a constant level.
Figure 5.15
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Using PI Control
Applications for PI control are listed in the table below.
Application
Machinery speed is fed back and adjusted to meet the target value. Synchronous control is performed using speed data from
Speed Control
other machinery as the target value.
Pressure Maintains constant pressure using pressure feedback.
Fluid Control Keeps flow at a constant level by feeding back flow data.
Temperature Control Maintains a constant temperature by controlling a fan with a thermostat.
YASKAWA ELECTRIC SIEP C710616 35D YASKAWA AC Drive E1000 Technical Manual
ON
ON
b4-01 b4-02
Figure 5.14 Timer Operation
PI input
PI Output
Figure 5.15 PI Operation
Description
ON
ON
b4-01 b4-02
Time
PI output
common_TMonly
I control
P control
Time
5.2 b: Application
On (Closed)
Off (Open)
On (Closed) common_TMonly
Off (Open)
Sensors Used
Tachometer
Pressure sensor
Flow rate sensor
Thermocoupler, Thermistor
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