Mitsubishi FX3U-4AD User Manual page 446

FX /FX /FX PLC User's Manual - Analog Control Edition
3G 3U 3UC
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)
TI3
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.
L-14
T
I3
T T
I2 I1
Integral time (T
0 < T
Integral time (T
0 < T
T
I3
T
I2 T
I1
Integral time (TI)
0 < TI3 < TI2 < TI1
TI2
TI1
Integral time (TI)
0 < TI3 < TI2 < TI1
TI3
TI2 TI1
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
Measured value in proportional operation
Measured value in PI operation
Time
Output in PI operation
Output in proportional operation
Time
Output of
"proportional operation + integral operation"
Output of integral operation
Output of proportional operation
) × Deviation (E)
Proportional gain (K
P
Time
3 Parameter
3.2 Details of Parameters