6F3B0253
Basic Hardware and Function 219
7. Instructions
FUN 156 PID3 Pre-derivati ve real PID
Expression
Input −[ A PID3 B → C ]− Output
Function
Performs PID (Proportional, Integral, Der ivative) control which is a fundamental method of feed-
back control. (Pre-derivative real PID a l gori thm) 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 f ilter is available for PV .
• Direct / reverse operation is selectable.
Execution condition
Input Operation Output
OFF Initializati on OFF
ON Ex ecute PID every setting int erval ON when
execution
Operand
Name Device Register ConstantI ndex
X Y R S T. C. XW YW RW SW T C D I J K
ATop of input data √√√√√√√
BTop of parameter √√√√√√√
CTop of output data √√√√√√
Input data Control par am eter Output data
AProcess input value PVC BProportional gain KPCManipulation v alue MV
A+1 A-mode set value ASV B+1 Integral t i m e TIC+1 Last error en-1
A+2 C-mode set value CSV B+2 Derivative time TDC+2 Last der i vative val ue Dn-1
A+3 M-mode MV input MMV B+3 Dead-band GP C+3 Last PV PVn-1
A+4 MV tracking input TMV B+4 A-mode initial SV ISV C+4 Last SV SVn-1
A+5 Mode setting MODE B+5 Input filter constant FT C+5 Integral rem ainder Ir
B+6 ASV differential limit DSV C+6 Derivati ve remainder Dr
B+7 MMV differential limit DMMV C+7 Internal MV MVn
A-mode: Auto mode B+8 Initial status ST S C+8 Internal counter C
C-mode: Cascade mode B+9 MV upper li mit 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