M-24
5 Example of Practical Programs (for Step Response Method)
FX
3G
/FX
3U
/FX
3UC
PLC User's Manual - Analog Control Edition
PID Instruction (FNC 88)
5.2 Program example of auto-tuning (step response method) and PID control
5.2 Program example of auto-tuning (step response method) and PID control
M8002
The mode of FX
2N
-4AD-TC is set.
Ch 1: Unused Ch 3: Unused
Ch 2: K type Ch 4: Unused
K500 D500 The target value is set (to 50°C).
K 70 D512 The input filter constant (
α
) is set
(to 70%).
K 0 D515
The output value upper limit is set
(to ON for 2 sec).
K2000 D532
The output value lower limit is set
(to ON for 0 sec).
K 0 D533
X010
PID control is started
after auto-tuning
PLS M0 The auto-tuning setting is started.
X011
PID control is started
(without auto-tuning)
M0
SET M1
Auto-tuning setting flag
K3000 D510
H0031 D511
K1800 D502
M1
Auto-tuning ON flag
K500 D510
M8002
Initial pulse
K 0 K 0 H3303 K 1
M8000
RUN monitor
K 0 K 10 D501 K 1
M8002
Initial pulse
RST D502
X11
PID control is started
(without auto-tuning)
D500 D501 D510 D502
X10
PID control is
started after
auto-tuning
The differential gain (K
D
) is set
(to 0%).
Auto-tuning ON flag
The sampling time (Ts) for auto-
tuning is set (to 3 sec).
Operation setting (ACT)
Auto-tuning is started.
The output value for auto-tuning is
set (to ON for 1.8 sec).
The sampling time (Ts) for normal
operation is set (to 500 ms).
Data is read from the channel 2 in
FX
2N
-4AD-TC.
The PID operation is initialized.
PID instruction is driven.
X010
PID control is started
(without auto-tuning)
PID control is
started after
auto-tuning
The PID operation is executed.
X011
M3
FNC 12
MOV
FNC 12
MOV
FNC 12
MOV
FNC 12
MOV
FNC 12
MOV
FNC 12
MOV
FNC 12
MOV
FNC 12
MOV
FNC 12
MOVP
FNC 79
TO
FNC 78
FROM
FNC 88
PID
Initial pulse