Product : ISaGRAF V3
Date : 26-August-1996
File : PID_AL.Complex PID algorithm implementation.htm
Subject : Complex PID algorithm implementation
Keywords: PID - PID_AL
A pid is a process regulator. Using the Feed Back concept, an output
is regulated according to the difference between what it is really
and what it should be.
PV is the output. At the entry the error e is calculated as the
difference SP-PV. The control calculates the action to do on the system
to keep the regulation.
System to command : for the simulation, it is a second order system that
has been simulated.
On the contrary, on a non regulated system we have :
Major points of the PID described here :
SP is the set point : value wanted at the output.
X0 (open loop case, in manual mode) is the non regulated value entering the system.
Xout (close loop case with regulation) is the regulated value entering the system.
CJ PID-Al description
call: - Auto:automatic or manual mode
Pv :Process output value
Sp :Set point value
X0 :Adjustment value: In manual mode, output pid controller equal to X0
Kp :Proportionality constant
Ti :Integral time constant
Td :derivative time constant
Ts :Sampling period
Min, Max : range of accepted values of Xout
return: - Xout : Command
prototype: - PID (Auto,Pv,Sp,X0,Kp,Ti,Td,Ts, Min, Max);
command := PID.Xout;
notes: - automatic mode must be set to false at init
- The implemented model is :
Theoretical Continue formula
Implemented Discret formula
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