Mitsubishi Electric FX3G User Manual page 512

FX /FX /FX /FX /FX
3S 3G 3GC 3U
PID Instruction (FNC 88)
Example 1: PI operation in heating (backward operation)
Target
value (SV)
Example 2: Proportional operation (P operation) in cooling (forward operation)
T
I3
Target
value(SV)
Important point
The integral operation changes the output so that the continuously generated deviation is eliminated.
As a result, the remaining deviation generated in the proportional operation can be eliminated.
M-14
PLC User's Manual - Analog Control Edition
3UC
T
I3
T T
I2 I1
Integral time (T
0 < T
Integral time (T
0 < T
T
I3
T
I2 T
I1
Integral time (T
0 < T
I3
T
I2
T
I1
Integral time (T
0 < T
I3
T
I3
T T
I2 I1
Deviation (EV)
Time
Integral time (T )
I
Measured value in PI operation
Measured value in proportional operation
)
I
< T < T
I3 I2 I1
Time
)
I
< T < T
I3 I2 I1
Output in PI operation
Output in proportional operation
Time
)
I
< T < T
I2 I1
Measured value in proportional operation
Measured value in PI operation
Time
)
I
< T < T
I2 I1
Output in PI operation
Output in proportional operation
Time
Output of
"proportional operation + integral operation"
Output of integral operation
Output of proportional operation
Proportional gain (K ) × Deviation (E)
P
Time
3 Parameter
3.2 Details of Parameters