Mitsubishi Electric MELSEC-L Special Instructions Manual page 231

Device Data item
(s)+10 MV change rate
limit (MVL)
(s)+11 PV change rate
limit (PVL)
(s)+12 (Fixed value)
(s)+13 Derivative gain
(K
)
D
(s)+14 (Fixed value)
(s)+15 (Fixed value)
Setting data for No. 2 loop (device: (s)+16 to (s)+29)
Description Setting range
With PID limits
Set the variation limit 0 to 2000
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.)
Set the variation limit 0 to 2000
between the previous PV and
the present PV.
When the PV variation is
greater than the limit value,
bit 0 (b0) of the alarm device
is set to '1'.
PV variation is not limited.
(Even if the PV variation
exceeds the limit value, the
actual PV variation is used as
it is for performing the PID
operation.)

0
Set a duration (delay in 0 to 32767
action) for derivative action. (unit: 0.01)
As the setting value
increases, the duration If setting value
becomes smaller and action > 30000
K
becomes closer to exact = Infinite ()
D
differential.
Ideal value K = 8.00
D

0
 0
Setting
side
Without PID
limits
-32768 to 32767 User
-32768 to 32767 User
0 User
0 to 32767 User
(unit: 0.01)
If setting value
> 30000
K
= Infinite ()
D
0 User
0 User
6 PID CONTROL INSTRUCTION
6.1 PID Control Instruction (Inexact Differential)
Processing when the
setting data are outside
the setting range
In the case of "With PID
limits", the PID operation is
performed after values are
replaced as follows:
• If the MVL value is less
than 0, the value is clipped
to 0.
• If the MVL value is
greater than 2000, the
value is clipped to 2000.
In the case of "With PID
limits", the PID operation is
performed after values are
replaced as follows:
• If the PVL value is less
than 0, the value is clipped
to 0.
• If the PVL value is greater
than 2000, the value is
clipped to 2000.

An error occurs and the PID
operation for the
corresponding loop is not
performed.


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