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6F3B0253
Basic Hardware and Function 219
7. Instructions
FUN 156 PID3 Pre-derivative real 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 Constant Index
X Y R S T. C. XW YW RW SW T C D I J K
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