Mitsubishi Electric MELSEC System Q, Special Instructions Manual

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6 PID CONTROL INSTRUCTION
6.2 PID Control Instruction (Exact Differential)
Setting data
Device Data item Description Setting range Setting
side Processing when the
setting data are outside
the setting range
With PID limits Without PID
limits
(s)+0 Operational
expression
selection Select the PID operational
expression.
*1
0: Forward
operation
1: Reverse
operation 0: Forward
operation
1: Reverse
operation User An error occurs and the PID
operation for the
corresponding loop is not
performed.
(s)+1 Sampling cycle
(T
S
)
Set the PID operation cycle. 1 to 6000
(unit: 10ms) 1 to 6000
(unit: 10ms) User
(s)+2 Proportional
constant (K
P
)
Proportional gain of PID
operation 1 to 10000
(unit: 0.01) 1 to 10000
(unit: 0.01) User An error occurs and the PID
operation for the
corresponding loop is not
performed.
(s)+3 Integral constant
(T
I
)
Constant that expresses the
magnitude of the integral
action (I action) effect.
Increasing the integral
constant slows down the
manipulated value change. 1 to 32767
(unit: 100ms)
If setting value
> 30000
T
I
= Infinite (

)
1 to 32767
(unit: 100ms)
If setting value
> 30000
T
I
= Infinite (

)
User
(s)+4 Derivative constant
(T
D
)
Constant that expresses the
magnitude of the derivative
action (D action) effect.
Increasing the derivative
constant causes significant
changes in the manipulated
value even with a slight
change of the control target. 0 to 30000
(unit: 10ms) 0 to 30000
(unit: 10ms) User
(s)+5 Filter coefficient (

) Set the degree of filtering to
be applied to the process
value.
The filtering effect decreases
as the value gets closer to 0. 0 to 100 0 to 100 User
(s)+6 MV lower limit
(MVLL) Set the lower limit for the
manipulated value (MV)
calculated in PID operation in
automatic mode.
If the MV is less than the set
lower limit value (MVLL), the
value is clipped to the MVLL. -50 to 2050 -32768 to 32767 User In the case of "With PID
limits", the PID operation is
not performed after values
are replaced as follows:
• If MVLL or MVHL value is
less than -50, the value is
clipped to -50.
• If MVLL or MVHL value is
greater than 2050, the
value is clipped to 2050.
(s)+7 MV upper limit
(MVHL) Set the upper limit for the
manipulated value calculated
in PID operation in automatic
mode.
If the MV is greater than the
set upper limit value (MVHL),
the value is clipped to the
MVHL. -50 to 2050 -32768 to 32767 User
(s)+8 MV change rate
limit (

MVL)
Set the variation limit
between the previous MV
and the present MV.
When the MV variation is
greater than the limit value,
bit 1 (b1) of the alarm device
is set to '1'.
MV variation is not limited.
(Even if the MV variation
exceeds the limit value, the
actual MV variation is used
as it is for calculating the
MV.) 0 to 2000 -32768 to 32767 User In the case of "With PID
limits", the PID operation is
performed after values are
replaced as follows:
•

MVL value is less than 0,
the value is clipped to 0.
•

MVL value is greater than
2000, the value is clipped
to 2000.