Inserting The Pid Instruction And Technological Object - Siemens SIMATIC S7 System Manual

The PID controller uses the following formula to calculate the output value for the
PID_Compact instruction.
y = K
y
w
K
p
T
1
T
D
The PID controller uses the following formula to calculate the output value for the PID_3Step
instruction.
Δ y = K
y
w
K
p
T
1
T
D
9.2.1

Inserting the PID instruction and technological object

STEP 7 provides two instructions for PID control:
● The PID_Compact instruction and its associated technological object provide a universal
● The PID_3Step instruction and its associated technological object provide a PID
After creating the technological object, you must configure the parameters (Page 337). You
also adjust the autotuning parameters ("pretuning" during startup or manual "fine tuning") to
commission the operation of the PID controller (Page 340).
S7-1200 Programmable controller
System Manual, 11/2011, A5E02486680-05
1
[
(b · w - x) +
p T · s
I
Output value
Setpoint value
Proportional gain
(P component)
Integral action time
(I component)
Derivative action time
(D component)
[
· s · (b · w - x) +
p
Output value
Setpoint value
Proportional gain
(P component)
Integral action time
(I component)
Derivative action time
(D component)
PID controller with tuning. The technological object contains all of the settings for the
control loop.
controller with specific settings for motor-activated valves. The technological object
contains all of the settings for the control loop. The PID_3Step controller provides two
additional Boolean outputs.
T · s
D
(w - x) + (c · w - x)
a · T · s + 1
D
x
s
a
b
c
1 T · s
D
(w - x) +
T · s a · T · s + 1
I D
x
s
a
b
c
102BTechnology instructions
]
Process value
Laplace operator
Derivative delay coefficient
(D component)
Proportional action weighting
(P component)
Derivative action weighting
(D component)
]
(c · w - x)
Process value
Laplace operator
Derivative delay coefficient
(D component)
Proportional action weighting
(P component)
Derivative action weighting
(D component)
9.2 PID control
325