Pid Algorithm - Siemens SIMATIC Manual

Continuous Temperature Controller FB 58 "TCONT_CP"
2.1.2

PID Algorithm

The schematic below is the block diagram of the PID algorithm:
SP_INT
GAIN
X
ER
Parameter assignment user interface
FB call interface
Parameter assignment user interface, FB call interface
PID Algorithm (GAIN, TI, TD, D_F)
The PID algorithm operates as a position algorithm. The proportional, integral
(INT), and derivative (DIF) actions are connected in parallel and can be activated
or deactivated individually. This allows P, PI, PD, and PID controllers to be
configured.
The controller tuning supports PI and PID controllers. Controller inversion is
implemented using a negative GAIN (cooling controller).
If you set TI and TD to 0.0, you obtain a pure P controller at the operating point.
The step response in the time range is:
LMN_Sum(t)
Where:
LMN_Sum(t)
ER (0)
GAIN
TI
TD
D_F
2-4
f()
PFAC_SP
INT
INT_HPOS
INT_HNEG
TI, I_ITL_ON,
I_ITLVAL
DIF
TD, D_F
= +
GAIN * ER(0)(1
is the manipulated variable in automatic mode of the controller
is the step change of the normalized error
is the controller gain
is the integral time
is the derivative time
is the derivative factor
DISV
+
−
t
1
+
)
t * D_F *
TD/D_F
e
TI
LMN_P
LMN_Sum
+
LMN_I
LMN_D
PID Temperature Control
A5E00125039-02