Mitsubishi FX3U-4AD User Manual page 445

FX /FX /FX PLC User's Manual - Analog Control Edition
3G 3U 3UC
PID Instruction (FNC 88)
3.2.4 Proportional gain (K
During the proportional operation, the output (MV) increases in proportion to the deviation (difference
between the target value (SV) and the measured value (PV)).
This deviation is called proportional gain (Kp), and expressed in the following relational expression:
Output (MV) = Proportional gain (K
The reciprocal of the proportional gain (K
As the proportional gain (K
(PV) be nearer to the target value (SV) becomes stronger.
Example 1: Proportional operation (P operation) in heating (backward operation)
Example 2: Proportional operation (P operation) in cooling (forward operation)
K
3.2.5 Integral time (T
During the integral operation, the time after deviation is generated until the integral operation output becomes
the proportional operation output. This is called integral time and is expressed as "T
As T becomes smaller, the integral operation becomes stronger.
I
): (S3)+3
P
) x Deviation (EV)
P
) is called proportional band.
P
) is larger (as shown in the example below), the motion to let the measured value
P
K
P3
K
P2
K
P1
K
K
K
P3
P1
P2
K K
P3 P2 P1
K K K
P3 P2 P1
): (S3)+4
I
Setting range: 0 to 32767 [ × 100 ms] "0" is handled as "∞" (no integration).
Setting range: 1 to 32767[%]
PID control: Proportional operation
Target value (SV)
Measured value (PV)
Remaining deviation
Proportional gain
K > K > K
P3 P2 P1
Time
Proportional gain
K > K > K
P3 P2 P1
Time
Proportional gain
K > K > K
P3 P2 P1
Measured value (PV)
Target value (SV)
Remaining deviation
Time
Proportional gain
K > K > K
P3 P2 P1
Time
PID operation: Integral operation
3 Parameter
3.2 Details of Parameters
".
I
L-13
K
L