46
PROSEC T3H
2. Expanded Functions
2.4.2 Essential PID (PID3)
FUN 156
PID3
Essential PID
Expression
Input
─
[
A
PID3
B
→
C
]
─
Output
Function
Performs PID (Proportional, Integral, Derivative) control which is a fundamental method of feed-back control.
(Pre-derivative real PID algorithm)
This PID3 instruction has the following features.
•
For derivative action, incomplete derivative is used to suppress interference of high-frequency noise and to
expand the stable application range,
•
Controllability and stability are enhanced in case of limit operation for MV, by using digital PID algorithm
succeeding to benefits of analog PID.
•
Auto, cascade and manual modes are supported in this instruction.
•
Digital filter is available for PV.
•
Direct / reverse operation is selectable.
Execution condition
Input Operation Output
OFF Initialization
OFF
ON
Execute PID every setting interval
ON when
execution
Operand
Name
Device
Register
Con-
Index
X Y S L R Z T. C. I O X
W
Y
W
S
W
L
W
R
W
W T C D F I
W
O
W
I J K
stant
A
Top of input
data
√
√
√
√
√
√
√
√
√
√
√
B
Top of
parameter
√
√
√
√
√
√
√
√
√
√
√
C
Top of
output data
√
√
√
√
√
√
√
√
√
√
Input data
Control parameter
Output data
A
Process input value
PVC
B
Proportional gain
K
P
C
Manipulation value
MV
A+1
A-mode set value
ASV
B+1
Integral time
T
I
C+1
Last error
e
n-1
A+2
C-mode set value
CSV
B+2
Derivative time
T
D
C+2
Last derivative value
D
n-1
A+3
M-mode MV input
MMV
B+3
Dead-band
GP
C+3
Last PV
PV
n-1
A+4
MV tracking input
TMV
B+4
A-mode initial SV
ISV
C+4
Last SV
SV
n-1
A+5
Mode setting
MODE
B+5
Input filter constant
FT
C+5
Integral remainder
Ir
B+6
ASV differential limit
DSV
C+6
Derivative remainder
Dr
B+7
MMV differential limit
DMMV
C+7
Internal MV
MV
n
A-mode: Auto mode
B+8
Initial status
STS
C+8
Internal counter
C
C-mode: Cascade mode
B+9
MV upper limit
MH
C+9
Control interval
∆∆∆∆
t
M-mode: Manual mode
B+10
MV lower limit
ML
B+11
MV differential limit
DMV
B+12
Control interval setting
n
