Principles for control
2.3 Characteristic values of the control section
PID control
20 Function Manual, 03/2017, A5E35300227-AC
Characteristic values of the control section
Determining the time response from the step response
Time response of the controlled system can be determined based on the time characteristic
of process value x following a step change of output value y. Most controlled systems are
self-regulating controlled systems.
The time response can be determined by approximation using the variables Delay time T
u
,
Recovery time T
g
and Maximum value X
max
. The variables are determined by applying
tangents to the maximum value and the inflection point of the step response. In many
situations, it is not possible to record the response characteristic up to the maximum value
because the process value cannot exceed specific values. In this case, the rate of rise v
max
is
used to identify the controlled system (v
max
= Δ
x
/Δ
t
).