Formulas
Original instructions
Transfer function
Depending on whether the mixed or parallel structure is being used, the transfer function is as follows:
Structure
Formulas
Mixed
Parallel
with α = scaling factor
Calculation formulas
The formulas actually used vary depending whether the function block uses the incremental or absolute form of the algorithm.
In a simplified form, the function block can use one of the following formulas:
Algorithm
ti
Formulas
Absolute
0
Incremental
>0
Explanation of formula variables
The meaning of the formula sizes is given in the following table:
Variable
Meaning
(new)
Value which is calculated on current execution of the function block
(old)
Value which is calculated on previous execution of the function block
OUT
Absolute value output
OUTD
Incremental value output
TermD
Value of the differential component
TermFF
Value of the feed forward component (disturbance compensation)
TermI
Value of the integral component
TermP
Value of the proportional component