Pid Algorithms; Standard Pid Algorithm - Siemens SIMATIC 505 User & Programmers Manual

5.2

PID Algorithms

5.2.1
Standard PID
Algorithm
5-4 Selected Functions
The TurboPlastic module provides two distinct user-selectable PID
algorithms that give different control responses (see PID, Section 1.3).
Algorithm selection depends on the machine controlled by the user and the
response desired.
The standard PID algorithm is one of several offered in the 505 series of
controllers, except that when a change of set point is requested, this new
setpoint value is immediately output. This provides an instantaneous or
"step" change in the output to the new setpoint value. PID control then
takes place about the setpoint value. In one case, you can select set point
output as an option; see constant 14, bit 8, page 2-19.
The basic equation for the standard PID algorithm is as follows:
Calculate integral constant term:
Calculate derivative constant term:
Calculate process variable:
Calculate new error term:
Calculate new bias term:
Calculate new output value: