1 OVERVIEW
1.3.5 Derivative action (D-action)
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(1) When a deviation occurs, the derivative action adds the manipulated value
proportional to the change speed to eliminate the deviation.
This can protect the control target from a sudden change due to disturbance.
(2) In the derivative action, the time from the deviation occurrence until the
manipulated value of the derivative action becomes that of the proportional action is
called the derivative time, and is indicated by T
(3) Figure 1.9 shows the derivative action for the step response with a constant
deviation.
(4) The derivative action is used in the PID action in combination with the proportional
and integral actions.
The PD action in combination with the proportional action, or the derivative action
by itself is not available.
T
D
*1: The PD action is not available for this module.
E
Time
K
E
P
Time
Fig. 1.9 Derivative action for step response
MELSEC-Q
.
D
Manipulated value of the proportional
action + derivative action
Manipulated value of the proportional
action
Manipulated value of the derivative
action
*1
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