Technical data

Table Of Contents
SFBs for Integrated Control
System Software for S7-300/400 System and Standard Functions - Volume 2/2
A5E00739858-01
27-21
The following figure shows the asymmetric curve of the three-step controller (ratio
factor = 0.5):
100%
-200%
PER_TM
PER_TM P_B_TM
P_B_ T M
PER_TM
PER_TM P_B_TM
P_B_ T M
Duration of the
pos. pulse
Duration of the
neg. pulse
Ratio Factor > 1
The pulse duration at the positive pulse output calculated from the input variable
multiplied by the period time is reduced by the ratio factor.
Dur. of negative pulse =
100
INV
PER_TM
INV
PER_TM
RATIOFAC
Dur. of positive pulse =
100