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

1 OVERVIEW

1.3 PID Operation

1.3.1 Operation method and formula

Set value (SV)
K : Proportional gain
P
T : Integral time
I
T :
Derivative time
D
Fig. 1.5 Algorithm of PID control in measured value incomplete differentiation
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The Q62HLC can perform PID control in measured value incomplete differentiation.
The PID control in measured value incomplete differentiation is an operation method
which puts the primary delay filter as the input for derivative control action, and
performs PID operation with the deviation (E) after eliminating the high-frequency noise
component.
(1) The algorithm of the PID control in measured value incomplete
differentiation is shown in Figure 1.5.
Control response
parameters
Slow
Normal
Fast
Derivative
η:
Laplace transform
s:
E: Deviation
(2) The formula used for the Q62HLC is shown below:
MV = K E + E + I
n P n n
T
I
Deviation (SV-PV)
E:
:
Sampling cycle
MV:
PID control in measured value incomplete differentiation output
Process value
PV:
Proportional gain
K :
P
T :
Integral time
I
Derivative time
T :
D
:
Derivative
I: Integral value
Derivative value
D:
Q62HLC
+
K (1 +
P
- E
T
T
D
+ D -
n-1
n-1
+ T + T
D
Disturbance D
+
1
)
T · s
-
I
Manipulated
value (MV)
K · T · s
P D
1 + η · T · s
D
D
PV - PV
n n-1
D
MELSEC-Q
Controlled object
G(s)
Process value (PV)
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