Справочник Пользователя для Mitsubishi Electronics Q64TCRTBWN

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An integral action is an action which continuously changes the manipulated value (MV) to eliminate the deviation (E) 
when there is any.
The offset caused by a proportional action can be eliminated.

In an integral action, the time from a deviation occurrence until when the manipulated value (MV) of the integral action 
becomes equals to that of the proportional action is called integral time, and is indicated as T

I

.

The following table describes the difference of actions depending on the value of T

I

, integral time.

The following figure shows an integral action of step responses where the deviation (E) is a fixed value.

An integral action is used as a PI action in combination with a proportional action, or PID action in combination with a 
proportional and derivative actions.
An integral action cannot be used by itself.

T

I

 is a small value

The integral effect gets large, and time to eliminate the offset gets short.
Though, the temperature process value (PV) tends to fluctuate around the set value.

T

I

 is a large value

The integral effect gets small, and time to eliminate the offset gets long.

E

Manipulated value of the Proportional action

Manipulated value of the Integral action

Manipulated value of the Proportional action + Integral action

Time

Time

T

I

Deviation

(E)

Manipulated

value (MV)

K

P  

E