Output Value Limits And Scaling - Siemens SIMATIC S7-1200 Function Manual

6.2.3.2

Output value limits and scaling

Depending on the operating mode, the PID output value (PidOutputSum) is calculated
automatically by the PID algorithm or by the manual value (ManualValue) or the configured
substitute output value (SubstituteOutput).
The PID output value is limited depending on the configuration:
● If the cooling is deactivated in the basic settings (Config.ActivateCooling = FALSE), the
value is limited to the high limit of the PID output value (heating)
(Config.Output.Heat.PidUpperLimit) and the low limit of the PID output value (heating)
(Config.Output.Heat.PidLowerLimit).
You can configure both limits at the horizontal axis of the scaling characteristic line in the
"OutputHeat / OutputCool" section. These are displayed in the "OutputHeat_PWM /
OutputCool_PWM" and "OutputHeat_PER / OutputCool_PER" sections, but cannot be
changed.
● If the cooling is activated in the basic settings (Config.ActivateCooling = TRUE), the value
is limited to the high limit of the PID output value (Config.Output.Heat.PidUpperLimit) and
the low limit of the PID output value (cooling) (Config.Output.Cool.PidLowerLimit).
You can configure both limits at the horizontal axis of the scaling characteristic line in the
"OutputHeat / OutputCool" section. These are displayed in the "OutputHeat_PWM /
OutputCool_PWM" and "OutputHeat_PER / OutputCool_PER" sections, but cannot be
changed.
The low limit of the PID output value (heating) (Config.Output.Heat.PidLowerLimit) and
the high limit of the PID output value (cooling) (Config.Output.Cool.PidUpperLimit) cannot
be changed and have to be assigned the value 0.0.
The PID output value is scaled and output at the outputs for heating and cooling. Scaling can
be specified separately for each output and is specified across 2 value pairs each, consisting
of a limit value of the PID output value and a scaling value:
Output
OutputHeat
OutputHeat_PWM
PID control
Function Manual, 03/2017, A5E35300227-AC
Value pair Parameter
Value pair 1 PID output value high limit (heating)
Config.Output.Heat.PidUpperLimit,
Scaled high output value (heating) Con-
fig.Output.Heat.UpperScaling
Value pair 2 PID output value low limit (heating)
Config.Output.Heat.PidLowerLimit,
Scaled low output value (heating) Con-
fig.Output.Heat.LowerScaling
Value pair 1 PID output value high limit (heating)
Config.Output.Heat.PidUpperLimit,
Scaled high PWM output value (heating)
Config.Output.Heat.PwmUpperScaling
Value pair 2 PID output value low limit (heating)
Config.Output.Heat.PidLowerLimit,
Scaled low PWM output value (heating)
Config.Output.Heat.PwmLowerScaling
Using PID_Temp
6.2 Configuring PID_Temp
167