Mitsubishi Electric MELSEC-Q series Programming Manual page 48

■For QnACPU
Setting Data Data Item
data No.
Common 1 Number of
setting loops
data
2 Number of
loops in one
scan
Data for 1 Selection of
each loop operational
expression
2 Sampling
cycle (T
3 Proportional
constant (K
4 Integral
constant (T
5 Derivative
constant (T
6 Filter
coefficient ()
7 MV Lower
limit (MVLL)
8 MV Upper
limit (MVHL)
9 MV change
rate limit (
MVL)
10 PV change
rate limit (
PVL)
5 PID CONTROL PROCEDURE
46
5.1 PID Control Data
Description
Sets the number of loops for which PID
operation will be executed.
Sets the number of loops for which single
PID operation will be executed when the
multiple loops reaches the sampling cycle
time.
Selects the PID operational expression
indicated in Section 3.2.2. ( Page 21
Operation expressions)
Sets the cycle of PID operation.
)
S
PID operation ratio
)
P
This constant expresses the magnitude of
) the integral operation (I operation) effect.
I
Increasing the integral constant slows
down the manipulated value change.
This constant expresses the magnitude of
) the derivative operation (D operation)
D
effect.
Increasing the derivative constant causes
a significant change in the manipulated
value even with slight change of the
control objective.
Sets the degree of filtering applied to the
process value.
The filtering effect decreases as the value
gets closer to 0.
In the automatic mode, sets the lower limit
for the MV (manipulated value) calculated
in PID operation.
When the MV is less than the MV lower
limit, the MVLL is used as the MV.
In the automatic mode, sets the upper limit
for the MV calculated in PID operation.
When the MV is greater than the MV upper
limit, the MVHL is used as the MV.
Sets the limit for variation between the
previous MV and present MV.
When the MV variation is greater than the
limit value, 1 is set for bit 1 (b1) of the
alarm device.
Does not limit the MV variation.
(If the MV variation is greater than the limit
value, it is used unchanged as the MV
variation to calculate the MV.)
Sets the limit for variation between the
previous PV and present PV.
When the PV variation is greater than the
limit value, 1 is set for bit 0 (b0) of the
alarm device. Does not limit the PV
variation.
(If the PV variation is greater than the limit
value, it is used unchanged as the PV
variation to perform the PID operation.)
Setting User Specifi-
Range cation Range
1 to 32 1 to 32
1 to 32 1 to 32
Forward 0 or 1
operation: 0
Reverse
operation: 1
0.01 to 1 to 6000
60.00s (unit: 10 ms)
0.01 to 1 to 10000
100.00 (unit: 0.01)
0.1 to 1 to 32767
3000.0s (unit: 100 ms)
Infinite()
(If the setting
for TI
exceeds
3000.0 s)
0.00 to 0 to 30000
300.00s (unit: 10 ms)
0 to 100% 0 to 100
-50 to 2050 -50 to 2050
-50 to 2050 -50 to 2050
0 to 2000 0 to 2000
0 to 2000 0 to 2000
Processing when Set Data is
Outside the Allowable Setting
Range
An error occurs and PID operation is
not executed for all loops.
An error occurs and PID operation for
the corresponding loop is not
executed.
An error occurs and PID operation for
the corresponding loop is not
executed.
An error occurs and PID operation for
the corresponding loop is not
executed.
PID operation is performed after
conversion into the following value.
• When the MVLL or MVHL value is
less than -50, it is converted into -
50.
• When the MVLL or MVHL value is
greater than 2050, it is converted
into 2050.
PID operation is performed after
conversion into the following value.
• When the MVL value is less than
0, it is converted into 0.
• When the MVL value is greater
than 2000, it is converted into
2000.
PID operation is performed after
conversion into the following value.
• When the PVL value is less than
0, it is converted into 0.
• When the PVL value is greater
than 2000, it is converted into
2000.