Siemens SIMATIC S7-1500T Function Manual

Principles for control
2.7 Selection of the controller structure for specified controlled systems
PID control
36 Function Manual, 03/2017, A5E35300227-AC
2.7
Selection of the controller structure for specified controlled systems
Selection of the Suitable Controller Structures
To achieve optimum control results, select a controller structure that is suitable for the
controlled system and that you can adapt to the controlled system within specific limits.
The table below provides an overview of suitable combinations of a controller structure and
controlled system.
Controlled system
Controller structure
P
PD
PI
PID
With dead time only Unsuitable Unsuitable Suitable Unsuitable
PT1 with dead time Unsuitable Unsuitable Well suited Well suited
PT2 with dead time Unsuitable Suited conditionally Well suited Well suited
Higher order Unsuitable Unsuitable Suited conditionally Well suited
Not self-regulating Well suited Well suited Well suited Well suited
The table below provides an overview of suitable combinations of a controller structure and
physical quantity.
Physical quantity
Controller structure
P
PD
PI
PID
Sustained control deviation
No sustained control deviation
Temperature For low perfor-
mance require-
ments and
proportional action
controlled systems
with T
u
/Tg < 0,1
Well suited The most suitable controller structures
for high performance requirements
(except for specially adapted special
controllers)
Pressure Suitable, if the
delay time is in-
considerable
Unsuitable The most suitable controller structures
for high performance requirements
(except for specially adapted special
controllers)
Flow rate Unsuitable, be-
cause required
GAIN range is
usually too large
Unsuitable Suitable, but inte-
gral action control-
ler alone often
better
Hardly required

Siemens SIMATIC S7-1500T Specifications

General

Brand	Siemens
Model	SIMATIC S7-1500T
Category	Controller
Language	English