Pid_Temp; Description Of Pid_Temp - Siemens SIMATIC S7-1200 Function Manual

Instructions

9.3 PID_Temp

9.3.4 PID_Temp
9.3.4.1

Description of PID_Temp

Description
The PID_Temp instruction provides a PID controller with integrated tuning for temperature
processes. PID_Temp can be used for pure heating or heating/cooling applications.
The following operating modes are possible:
● Inactive
● Pretuning
● Fine tuning
● Automatic mode
● Manual mode
● Substitute output value with error monitoring
For a more detailed description of the operating modes, see the State parameter.
PID algorithm
PID_Temp is a PIDT1 controller with anti-windup and weighting of the proportional and
derivative actions. The PID algorithm operates according to the following equation (control
zone and dead zone deactivated):
The table below shows the meaning of the icons used in the equation and in the subsequent
figures.
Icon
y
K
p
s
b
w
x
T
I
378
Description
Output value of the PID algorithm
Proportional gain
Laplace operator
Proportional action weighting
Setpoint
Process value
Integral action time
Associated parameters of the
PID_Temp instruction
-
Retain.CtrlParams.Heat.Gain
Retain.CtrlParams.Cool.Gain
CoolFactor
-
Retain.CtrlParams.Heat.PWeighting
Retain.CtrlParams.Cool.PWeighting
CurrentSetpoint
ScaledInput
Retain.CtrlParams.Heat.Ti
Retain.CtrlParams.Cool.Ti
Function Manual, 03/2017, A5E35300227-AC
PID control