Siemens SIMATIC S7-1200 Function Manual page 322

Instructions
9.2 PID_3Step
Tag
SavePosition
CurrentSetpoint
CancelTuningLevel
Progress
Config.InputPerOn
Config.OutputPerOn
Config.InvertControl
Config.FeedbackOn
Config.FeedbackPerOn
Config.ActuatorEndStopOn
Config.InputUpperLimit
Config.InputLowerLimit
322
Data type Default
REAL 0.0
REAL 0.0
REAL 10.0
REAL 0.0
BOOL TRUE
BOOL FALSE
BOOL FALSE
BOOL FALSE
BOOL FALSE
BOOL FALSE
REAL 120.0
REAL 0.0
Description
Substitute output value
If ErrorBehaviour = TRUE, the actuator is moved to a posi-
tion that is safe for the plant when an error occurs. As soon
as the substitute output value has been reached, PID_3Step
switches the operating mode according to ActivateRecov-
erMode.
Currently active setpoint. This value is frozen at the start of
tuning.
Permissible fluctuation of setpoint during tuning. Tuning is
not canceled until:
Setpoint > CurrentSetpoint + CancelTuningLevel
•
or
Setpoint < CurrentSetpoint - CancelTuningLevel
•
Progress of tuning as a percentage (0.0 - 100.0)
If InputPerOn = TRUE, the Input_PER parameter is used. If
InputPerOn = FALSE, the Input parameter is used.
If OutputPerOn = TRUE, the Output_PER parameter is
used. If OutputPerOn = FALSE, the Ouput_UP and Out-
put_DN parameters are used.
Invert control logic
If InvertControl = TRUE, an increasing control deviation
causes a reduction in the output value.
If FeedbackOn = FALSE, a position feedback is simulated.
Position feedback is generally activated when Feed-
backOn = TRUE.
FeedbackPerOn is only effective when Feed-
backOn = TRUE.
If FeedbackPerOn = TRUE, the analog input is used for the
position feedback (Feedback_PER parameter).
If FeedbackPerOn = FALSE, the Feedback parameter is
used for the position feedback.
If ActuatorEndStopOn = TRUE, the digital position feedback
Actuator_L and Actuator_H are taken into consideration.
High limit of the process value
Input and Input_PER are monitored to ensure adherence to
this limit.
At the I/O input, the process value can be a maximum of
18% higher than the standard range (overrange). An error is
no longer signaled due to a violation of the "Process value
high limit". Only a wire-break and a short-circuit are recog-
nized and PID_3Step reacts according to the configured
reaction to error.
InputUpperLimit > InputLowerLimit
Low limit of the process value
InputLowerLimit < InputUpperLimit
Function Manual, 03/2017, A5E35300227-AC
PID control