About The Pid Operation; Operation Method And Formula - Mitsubishi Electric MELSEC Q Series User Manual

1 GENERAL DESCRIPTION

1.3 About the PID Operation

1.3.1 Operation method and formula

SV(Set value)
Kp
: Proportional gain
Ti
: Integral time
T
: Derivative time
D
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The Q64TC can perform PID control in process-value incomplete differentiation.
The PID control in process-value incomplete differentiation is an operation method
which puts the first-order delay filter as the input for derivative control action, and
performs PID operation with the error deviation (E) after deleting the high-frequency
noise component.
(1) The algorithm of the PID control in process-value incomplete
differentiation is shown in Figure 1.6.
Control response
parameters
Slow
Normal control
Fast
: Derivative gain
S : Laplace transform conversion
Fig. 1.6 Algorithm of PID control in process-value incomplete differentiation
(2) The formula used for the Q64TC is shown below:
MV = MV
n n-1
: Sampling period
MV : Incomplete derivative output
PV : Process value
T : Derivative time
D
1
: Derivative gain
search engine
Q64TC
+
Kp(1+
-
T
D
(PV - PV ) -
+
n-1 n
T
+ T
D
MELSEC-Q
Disturbance D
Control object
1
+
)
G(s)
Ti s
MV
-
Kp T s
D
1+ T
D S
PV(Process value)
MV
n-1
D
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