Siemens SIMATIC S7-1500T Function Manual

Instructions
9.3 PID_Temp
PID control
Function Manual, 03/2017, A5E35300227-AC
445
9.3.4.11
PwmPeriode tag
If the PID algorithm sampling time (Retain.CtrlParams.Heat.Cycle or
Retain.CtrlParams.Heat.Cycle) and thus the time period of the pulse width modulation is very
high when you use OutputHeat_PWM or OutputCool_PWM, you can define a deviating
shorter time period at the Config.Output.Heat.PwmPeriode or
Config.Output.Cool.PwmPeriode parameters to improve the smoothness of the process
value.
Time period of the pulse width modulation at OutputHeat_PWM
Time period of the PWM at output OutputHeat_PWM depending on
Config.Output.Heat.PwmPeriode:
● Heat.PwmPeriode = 0.0 (default)
The sampling time of the PID algorithm for heating (Retain.CtrlParams.Heat.Cycle) is
used as time period of the PWM.
● Heat.PwmPeriode > 0.0
The value is rounded off to an integer multiple of the PID_Temp sampling time
(CycleTime.Value) and used as time period of the PWM.
The value must meet the following conditions:
– Heat.PwmPeriode ≤ Retain.CtrlParams.Heat.Cycle
– Heat.PwmPeriode > Config.Output.Heat.MinimumOnTime
– Heat.PwmPeriode > Config.Output.Heat.MinimumOffTime
Time period of the pulse width modulation at OutputCool_PWM
Time period of the PWM at output OutputCool_PWM depending on
Config.Output.Cool.PwmPeriode and the method for heating/cooling:
● Cool.PwmPeriode = 0.0 and cooling factor (Config.AdvancedCooling = FALSE):
The sampling time of the PID algorithm for heating (Retain.CtrlParams.Heat.Cycle) is
used as time period of the PWM.
● Cool.PwmPeriode = 0.0 and PID parameter switching (Config.AdvancedCooling =
TRUE):
The sampling time of the PID algorithm for cooling (Retain.CtrlParams.Cool.Cycle) is
used as time period of the PWM.
● Cool.PwmPeriode > 0.0:
The value is rounded off to an integer multiple of the PID_Temp sampling time
(CycleTime.Value) and used as time period of the PWM.
The value must meet the following conditions:
– Cool.PwmPeriode ≤ Retain.CtrlParams.Cool.Cycle or Retain.CtrlParams.Heat.Cycle
– Cool.PwmPeriode > Config.Output.Cool.MinimumOnTime
– Cool.PwmPeriode > Config.Output.Cool.MinimumOffTime

Siemens SIMATIC S7-1500T Specifications

General

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