Step Response Method; Parameters To Be Set By Auto-Tuning (Step Response Method; Auto-Tuning Procedure - Mitsubishi Electric FX3G User Manual

FX /FX /FX /FX /FX
3S 3G 3GC 3U 3UC
PID Instruction (FNC 88)
4.2

Step Response Method

4.2.1

Parameters to be set by auto-tuning (step response method)

Parameter
Operation setting (ACT)
Proportional gain (K
4.2.2

Auto-tuning procedure

1
Transferring the output value for auto-tuning to the output value
Set the output value for auto-tuning to the maximum available output value multiplied by 0.5 to 1 for
the output equipment.
2
Setting the parameter
tuning according to the system
Note that auto-tuning may not be executed normally if the cautions described below are not fol-
lowed
1. Set items
Set item and parameter
Target value (SV)
Sampling time (T
S
Input filter (α)
Differential gain (K
Others
2. Cautions on setting
1) Difference between the target value (SV) and the measured value (PV)
If the difference between the target value (SV) and the measured value (PV) is less than 150 when auto-
tuning is started, auto-tuning is not executed normally.
Accordingly, if the difference is less than 150, set the target value for auto-tuning.
Set the target value again when auto-tuning is completed.
Set item
Target value (SV)
2) Sampling time (T
Make sure the sampling time is set for auto-tuning to 1 second (1000 ms) or more.
It is recommended that the sampling time is set to that it is considerably longer than the output change
cycle.
3
Setting to ON bit 4 of
When the variation from the measured value at the start of auto-tuning to the target value reaches
1/3 or more, auto-tuning is completed. And bit 4 of
automatically set to OFF.
1. Important point
Start auto-tuning while the system is stable.
If the system is unstable when auto-tuning is started, auto-tuning may not be executed normally.
PLC User's Manual - Analog Control Edition
Setting position
S +1, bit 0 (operation direction)
3
)
P S +3
3
, target value (SV), etc. that cannot be set in auto-
S
3
The difference from the measured value (PV) should be 150 or more.
S
1
(For the details, refer to "2. Cautions on setting" below.)
) 1,000 ms or more (For the details, refer to "2. Cautions on setting" below.)
S
3
S
+2
3
) When setting the input filter, set the differential gain to "0" usually.
D S +5
3
Set other items, as necessary.
Setting in PID instruction
S
1
)
S
S
3
+1 (operation setting ACT) to start auto-tuning
S
3
Parameter
Integral time (T
Differential time (T
Remarks
Make sure that the difference from the measured value is 150 or
more when auto-tuning is started.
+1 (operation setting ACT) is
S
3
4 Auto-Tuning
4.2 Step Response Method
Setting position
)
I S +4
3
)
D S +6
3
D
M-21
K
L
M