Pid Parameter Settings - Siemens SIMATIC S7-1200 Function Manual

2.8

PID parameter settings

Rule of Thumb for the Parameter Setting
Instead of v
In the case of controllers with PID structure the setting of the integral action time and
differential-action time is usually coupled with each other.
The ratio TI / TD lies between 4 and 5 and is optimal for most controlled systems.
Non-observance of the differential-action time TD is uncritical at PD controllers.
In the case of PI and PID controllers, control oscillations occur if the integral action time TI
has been select by more than half too small.
An integral action time that is too large slows down the settling times of disturbances. One
cannot expect that the control loops operate "optimally" after the first parameter settings.
Experience shows that adjusting is always necessary, when a system exists that is "difficult
to control" with T
PID control
Function Manual, 03/2017, A5E35300227-AC
Controller structure
P
PI
PD
PID
PD/PID
= ∆ / ∆ , you can use X
max x t
/ T > 0.3.
u g
GAIN ≈ v × T [° C ]
max u
GAIN ≈ 1.2 × v × T [° C ]
max u
TI ≈ 4 × T [ min ]
u
GAIN ≈ 0.83 × v × T [° C ]
max u
TD ≈ 0.25 × v × T [ min ]
max u
TM_LAG ≈ 0.5 × TD[ min ]
GAIN ≈ 0.83 × v × T [° C ]
max u
TI ≈ 2 × T [ min ]
u
TD ≈ 0.4 × T [ min ]
u
TM_LAG ≈ 0.5 × TD[ min ]
GAIN ≈ 0.4 × v × T [° C ]
max u
TI ≈ 2 × T [ min ]
u
TD ≈ 0.4 × T [ min ]
u
TM_LAG ≈ 0.5 × TD[ min ]
/ T .
max g
Principles for control
2.8 PID parameter settings
Setting
37