Hitachi J300U Series instruction manual Appendix 8 PID Function, Wiring Sketch, PID Gain

Appendix 8 PID Function

1.Function

The PID (Proportional, Integral, Differential) control functions can apply to controlling of the air (water) amount of a fan pump, etc., as well as controlling of pressure within a fixed value.

Set the reference signal according to the frequency setting method or the internal level.

Set the feed-back signal according to the analog voltage input (0 to 5V or 0 to 10V) or analog current input (4 to 20 mA).

[Wiring Sketch]

0 to 10 V Reference

0 to 5 V

4 to 20 mA

or Internal level 0 to 200%

J300

Load (Fan Pump, etc.)

Sensor

Transducer

Feed-back Signal (0 to 5 V, 0 to 10 V, 4 to 20 mA)

2.PID Gain

If the response is not stabilized in a PID control operation, adjust the gains as follows according to the symptom of the inverter.

•The change of controlled variable is slow even when the target value is changed.

—Increase the P gain.

•The change of controlled variable is fast, but not stable.

—Decrease the P gain.

•It is difficult to make the target value match with the controlled variable.

—Decrease the I gain.

•Both the target value an the controlled variable are not stable. They match after oscillation.

—Increase the I gain.

•The response is slow even when the P gain is increased.

—Increase the D gain.

•The response is not stabilized due to oscillation even when the P gain is increased.

—Decrease the D gain.

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