YASKAWA CIPR-GA50C series Technical Manual page 499

target value to the detected value. Use this function to adjust the drive output to accurately match the flow,
pressure, and temperature in the application match the target value.
Use a combination of these controls to increase the performance:
• P control
P control has a proportional effect on the deviation. It outputs the product (the controlled output) proportional to
the deviation. You cannot use only the offset from P control to get to zero deviation.
• I control
I control is the integral of the deviation. It uses an integral value of the deviation to output the product (the
controlled output). I control helps align the feedback value and the target value. If you use only a proportional
effect (P control), it will cause and offset. Use a proportional effect with integral control, and the offset will
disappear over time.
• D control
D control is the derivative of the deviation. D control has an effect on drive output when there are sudden, large
changes in the deviation or feedback value. It quickly returns drive output to the value before the sudden
change. It multiplies a time constant by a derivative value of the deviation (slope of the deviation), and adds that
result to PID input to calculate the deviation of the signal, then it corrects the deviation.
Note:
D control has causes less stable operation because the noise changes the deviation signal. Use D control only when necessary.
■
PID Control Operation
Figure 12.28 shows PID control operation. The modified output (output frequency) changes when the drive uses
PID control to keep the deviation (the difference between the target value and the feedback value) constant.
■
PID Control Applications
Table 12.29 shows applications for PID control.
Application
Speed Control
Pressure control
Flow control
Temperature control
■
Input Methods for the PID Setpoint
Use b5-01 [PID Mode Setting] to select how the PID setpoint is input to the drive.
When b5-01 = 1 or 2 [Standard or Standard (D on feedback)], either the frequency reference set in b1-01
[Frequency Reference Selection 1] or b1-15 [Frequency Reference Selection 2] will be the PID setpoint, or the
one of the inputs in Table 12.30
YASKAWA SIEPC71061753A GA500 Technical Manual
Figure 12.28 PID Control Operation
Table 12.29 PID Control Applications
Control Content
• The drive uses a feedback signal for the machine
speed, and adjusts that speed to align with the target
value.
• The drive uses speed data from other machinery as the
target value to do synchronous control. The drive then
adds that target value to the feedback from the
machine it is operating to align its speed with the other
machinery.
The drive uses feedback from the actual pressure to hold
constant pressure.
The drive uses feedback from the actual flow to hold
constant flow.
The drive uses feedback from the actual temperature to
control a fan and hold constant temperature.
will be the PID setpoint.
12.3 b: Application
Sensors Used
Tacho generator
Pressure sensor
Flow rate sensor
Thermocoupler, thermistor
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