Siemens SIMATIC S7-1200 Function Manual page 424

Instructions
9.3 PID_Temp
Tag
PIDCtrl.PIDInit
Retain.CtrlParams.SetByUser
Retain.CtrlParams.Heat.Gain
Retain..CtrlParams.Heat.Ti
Retain.CtrlParams.Heat.Td
Retain.CtrlParams.Heat
.TdFiltRatio
424
Data type Default
BOOL FALSE
BOOL FALSE
REAL 1.0
REAL 20.0
REAL 0.0
REAL 0.2
Description
PIDCtrl.PIDInit is available as of PID_Temp version 1.1.
If PIDCtrl.PIDInit = TRUE in "Automatic mode", the integral
action PIDCtrl.IOutputOld is pre-assigned automatically as
if PidOutputSum = OverwriteInitialOutputValue in the pre-
vious cycle. This can be used for a Override control with
PID_Temp (Page 202).
If the PID parameters are entered manually in the configu-
ration editor, SetByUser = TRUE.
This parameter is used for display in the editors and does
not influence the control algorithm.
SetByUser is retentive.
Active proportional gain for heating
Heat.Gain is retentive.
Heat.Gain ≥ 0.0
Active integral action time for heating in seconds
The integral action for heating is switched off with
Heat.CtrlParams.Ti = 0.0.
Heat.Ti is retentive.
100000.0 ≥ Heat.Ti ≥ 0.0
Active derivative action time for heating in seconds
The derivative action for heating is switched off with
Heat.CtrlParams.Td = 0.0.
Heat.Td is retentive.
100000.0 ≥ Heat.Td ≥ 0.0
Active derivative delay coefficient for heating
The derivative delay coefficient delays the effect of the
derivative action.
Derivative delay = derivative action time × derivative delay
coefficient
0.0: Derivative action is effective for one cycle only and
•
therefore almost not effective.
0.5: This value has proved useful in practice for con-
•
trolled systems with one dominant time constant.
> 1.0: The greater the coefficient, the longer the effect
•
of the derivative action is delayed.
Heat.TdFiltRatio is retentive.
Heat.TdFiltRatio ≥ 0.0
Function Manual, 03/2017, A5E35300227-AC
PID control