Static tags of PID_3Step V2 (S7-1200, S7-1500)

Static tags of PID_3Step V2

Note
Change the tags identified with (1) only in "Inactive" mode to prevent malfunction of the
PID controller.

The names of the following variables apply both to the data block and to access via the
Openness API.

Tag Data Default Description

type

In manual mode, each rising edge opens the

valve by 5% of the total control range or for the
FALS duration of the minimum motor transition time.
ManualUpInternal BOOL
E ManualUpInternal is only evaluated if you are
not using Output_PER or a position feedback.
This tag is used in the commissioning dialog.
In manual mode, every rising edge closes the
valve by 5% of the total control range or for the
FALS duration of the minimum motor transition time.
ManualDnInternal BOOL
E ManualDnInternal is only evaluated if you are
not using Output_PER or position feedback.
This tag is used in the commissioning dialog.
The ActivateRecoverMode V2 tag determines
ActivateRecoverMode BOOL TRUE
the reaction to error.
Activate operating mode at Mode parameter af-
ter CPU restart
If RunModeByStartup = TRUE, PID_3Step starts
RunModeByStartup BOOL TRUE in the operating mode saved in the Mode param-
eter after CPU startup.
If RunModeByStartup = FALSE, PID_3Step re-
mains in "Inactive" mode after CPU startup.
If LoadBackUp = TRUE, the last set of PID pa-
FALS rameters is reloaded. The set was saved prior to
LoadBackUp BOOL
E the last tuning. LoadBackUp is automatically set
back to FALSE.
Unit of measurement of the process value and
setpoint, e.g., ºC, or ºF.
PhysicalUnit serves the display in the editors
PhysicalUnit INT 0 and has no influence on the behavior of the con-
trol algorithm in the CPU.
When importing PID_3Step via the Openness
API, PhysicalUnit is reset to the default value.
Physical quantity of the process value and set-
PhysicalQuantity INT 0
point, e.g., temperature

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

PhysicalQuantity serves the display in the edi-

tors and has no influence on the behavior of the
control algorithm in the CPU.
When importing PID_3Step via the Openness
API, PhysicalQuantity is reset to the default val-
ue.
If ErrorBehaviour = FALSE and an error has oc-
curred, the valve stays at its current position and
the controller switches directly to "Inactive" or
"Error monitoring" mode.
If ErrorBehaviour = TRUE and an error occurs,
the actuator moves to the substitute output value
and only then switches to "Inactive" or "Error
monitoring" mode.
FALS
ErrorBehaviour BOOL If the following errors occur, you can no longer
E
move the valve to a configured substitute output
value.
• 2000h: Invalid value at Feedback_PER pa-
rameter.
• 4000h: Invalid value at Feedback parameter.
• 8000h: Error during digital position feedback.
• 20000h: Invalid value at SavePosition tag.
The Warning tag shows the warnings since Re-
set = TRUE or ErrorAck =TRUE. Warning is re-
tentive.
DWO DW#1 Cyclic warnings (for example, process value
Warning warning) are shown until the cause of the warn-
RD 6#0
ing is removed. They are automatically deleted
once their cause has gone. Non-cyclic warnings
(for example, point of inflection not found) re-
main and are deleted like errors.
Substitute output value
If ErrorBehaviour = TRUE, the actuator is moved
to a position 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 ActivateReco-
verMode.
The permitted value range is determined by the
SavePosition REAL 0.0 configuration.
• Config.FeedbackOn = FALSE and Config.Out-
putPerOn = FALSE:
SavePosition = 0.0 or 100.0
• Config.FeedbackOn = TRUE or Config.Out-
putPerOn = TRUE:
Config.OutputUpperLimit ≥ SavePosition ≥
Config.OutputLowerLimit

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

Currently active setpoint. This value is frozen at

CurrentSetpoint REAL 0.0
the start of tuning.
Permissible fluctuation of setpoint during tuning.
Tuning is not canceled until:
• Setpoint > CurrentSetpoint + CancelTuningLe-
CancelTuningLevel REAL 10.0 vel
or
• Setpoint < CurrentSetpoint - CancelTuningLe-
vel
Progress REAL 0.0 Progress of tuning as a percentage (0.0 - 100.0)
If InputPerOn = TRUE, the Input_PER parame-
Config.InputPerOn(1) BOOL TRUE ter is used. If InputPerOn = FALSE, the Input pa-
rameter is used.
If OutputPerOn = TRUE, the Output_PER pa-
Config.OutputPer- FALS rameter is used. If OutputPerOn = FALSE, the
BOOL
On(1) E Ouput_UP and Output_DN parameters are
used.
Invert control logic
Config.InvertCon- FALS
BOOL If InvertControl = TRUE, an increasing control
trol(1) E
deviation causes a reduction in the output value.
If FeedbackOn = FALSE, a position feedback is
Config.Feedback- FALS simulated.
BOOL
On(1) E Position feedback is generally activated when
FeedbackOn = TRUE.
FeedbackPerOn is only effective when Feed-
backOn = TRUE.

Config.FeedbackPer- If FeedbackPerOn = TRUE, the analog input is

FALS
BOOL used for the position feedback (Feedback_PER
On(1) E
parameter).
If FeedbackPerOn = FALSE, the Feedback pa-
rameter is used for the position feedback.
Config.ActuatorEnd- If ActuatorEndStopOn = TRUE, the digital posi-
FALS
BOOL tion feedback Actuator_L and Actuator_H are
StopOn(1) E
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
Config.InputUpperLi- maximum of 18% higher than the standard
REAL 120.0 range (overrange). An error is no longer signaled
mit(1)
due to a violation of the "Process value high lim-
it". Only a wire-break and a short-circuit are rec-
ognized and PID_3Step reacts according to the
configured reaction to error.
InputUpperLimit > InputLowerLimit
Config.InputLowerLi- Low limit of the process value
REAL 0.0
mit(1) InputLowerLimit < InputUpperLimit

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

Warning high limit of the process value

If you set InputUpperWarning outside the proc-
ess value limits, the configured absolute process
value high limit is used as the warning high limit.
Config.InputUpper- +3.40
REAL 2822e If you configure InputUpperWarning within the
Warning(1) +38 process value limits, this value is used as the
warning high limit.
InputUpperWarning > InputLowerWarning
InputUpperWarning ≤ InputUpperLimit
Warning low limit of the process value
If you set InputLowerWarning outside the proc-
ess value limits, the configured absolute process
value low limit is used as the warning low limit.
Config.InputLower- -3.402
REAL 822e+ If you configure InputLowerWarning within the
Warning(1) 38 process value limits, this value is used as the
warning low limit.
InputLowerWarning < InputUpperWarning
InputLowerWarning ≥ InputLowerLimit
High limit of output value
The following value range is permitted:
Config.OutputUpper-
REAL 100.0 UpperPointOut ≥ OutputUpperLimit > OutputLo-
Limit(1)
werLimit
For more details, see OutputLowerLimit.
Low limit of output value
The following value range is permitted:
OutputUpperLimit > OutputLowerLimit ≥ Lower-
PointOut
When using Output_PER, an output value limit
of -100% corresponds to the value Out-
put_PER = -27648; 100% correspond to the val-
Config.OutputLower- ue Output_PER = 27648.
REAL 0.0
Limit(1)
If OutputPerOn = FALSE and Feedback-
On = FALSE, OutputLowerLimit and OutputUp-
perLimit are not evaluated.
Output_UP and Output_DN are then reset at Ac-
tuator_H = TRUE or Actuator_L = TRUE (if Ac-
tuatorEndStopOn = TRUE) or after a travel time
of Config.VirtualActuatorLimit * Retain.Transi-
tTime/100 (if ActuatorEndStopOn = FALSE).
High limit of setpoint
Config.SetpointUp- +3.40 If you set SetpointUpperLimit outside the proc-
REAL 2822e ess value limits, the configured absolute process
perLimit(1) +38 value high limit is preassigned as the setpoint
high limit.

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

If you configure SetpointUpperLimit within the

process value limits, this value is used as the
setpoint high limit.
Low limit of the setpoint
If you set SetpointLowerLimit outside the proc-
- ess value limits, the configured absolute process
Config.SetpointLo- 3.4028 value low limit is preassigned as the setpoint low
REAL
werLimit(1) 22e+3 limit.
8
If you set SetpointLowerLimit within the process
value limits, this value is used as the setpoint
low limit.
Minimum ON time
Minimum time in seconds for which the servo
Config.MinimumOn- drive must be switched on.
REAL 0.0
Time(1)
Config.MinimumOnTime is only effective if Out-
put_UP and Output_DN are used (Config.Out-
putPerOn = FALSE).
Minimum OFF time
Minimum time in seconds for which the servo
Config.MinimumOff- drive must be switched off.
REAL 0.0
Time(1)
Config.MinimumOffTime is only effective if Out-
put_UP and Output_DN are used (Config.Out-
putPerOn = FALSE).
If all the following conditions have been satis-
fied, the actuator is moved in one direction for
the maximum period of VirtualActuatorLimit ×
Retain.TransitTime/100 and the warning 2000h
is output:
• Config.OutputPerOn = FALSE
• Config.ActuatorEndStopOn = FALSE
Config.VirtualActua-
REAL 150.0
• Config.FeedbackOn = FALSE
torLimit(1)
If Config.OutputPerOn = FALSE and Config.Ac-
tuatorEndStopOn = TRUE or Config.Feedback-
On = TRUE, only the warning 2000h is output.
If Config.OutputPerOn = TRUE, VirtualActuator-
Limit is not taken into consideration.
As of PID_3Step Version 2.3 the monitoring and
limiting of the travel time can be deactivated with
Config.VirtualActuatorLimit = 0.0.
Scaling Input_PER high
Config.InputScal- 27648. Input_PER is converted to a percentage based
REAL on the two value pairs UpperPointOut, Upper-
ing.UpperPointIn(1) 0
PointIn and LowerPointOut, LowerPointIn of the
InputScaling structure.
Scaling Input_PER low
Config.InputScal-
REAL 0.0 Input_PER is converted to a percentage based
ing.LowerPointIn(1)
on the two value pairs UpperPointOut, Upper-

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

PointIn and LowerPointOut, LowerPointIn of the

InputScaling structure.
Scaled high process value
Config.InputScal- Input_PER is converted to a percentage based
REAL 100.0 on the two value pairs UpperPointOut, Upper-
ing.UpperPointOut(1)
PointIn and LowerPointOut, LowerPointIn of the
InputScaling structure.
Scaled low process value
Config.InputScal- Input_PER is converted to a percentage based
REAL 0.0 on the two value pairs UpperPointOut, Upper-
ing.LowerPointOut(1)
PointIn and LowerPointOut, LowerPointIn of the
InputScaling structure.
Scaling Feedback_PER high
Config.FeedbackScal- 27648. Feedback_PER is converted to a percentage
REAL based on the two value pairs UpperPointOut,
ing.UpperPointIn(1) 0
UpperPointIn and LowerPointOut, LowerPointIn
of the FeedbackScaling structure.
Scaling Feedback_PER low
Config.FeedbackScal- Feedback_PER is converted to a percentage
REAL 0.0 based on the two value pairs UpperPointOut,
ing.LowerPointIn(1)
UpperPointIn and LowerPointOut, LowerPointIn
of the FeedbackScaling structure.
High endstop
Feedback_PER is converted to a percentage
based on the two value pairs UpperPointOut,
UpperPointIn and LowerPointOut, LowerPointIn
of the FeedbackScaling structure.
The permitted value range is determined by the
Config.FeedbackScal- configuration.
REAL 100.0
ing.UpperPointOut(1)
• FeedbackOn = FALSE:
UpperPointOut = 100.0
• FeedbackOn = TRUE:
UpperPointOut = 100.0 or 0.0
UpperPointOut ≠ LowerPointOut
Low endstop
Feedback_PER is converted to a percentage
based on the two value pairs UpperPointOut,
UpperPointIn and LowerPointOut, LowerPointIn
of the FeedbackScaling structure.
Config.FeedbackScal- The permitted value range is determined by the
REAL 0.0 configuration.
ing.LowerPointOut(1)
• FeedbackOn = FALSE:
LowerPointOut = 0.0
• FeedbackOn = TRUE:
LowerPointOut = 0.0 or -100.0

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

LowerPointOut ≠ UpperPointOut
If InvertDirection = FALSE, the valve is fully
opened, closed, and then reopened in order to
GetTransitTime.Inver- FALS determine the valve transition time.
BOOL
tDirection E
If InvertDirection = TRUE, the valve is fully
closed, opened, and then closed again.
If SelectFeedback = TRUE, then Feed-
back_PER, or Feedback is taken into considera-
GetTransitTime.Se- FALS tion in the transition time measurement.
BOOL
lectFeedback E If SelectFeedback = FALSE, then Actuator_H
and Actuator_L are taken into consideration in
the transition time measurement.
Current phase of the transition time measure-
ment
• State = 0: Inactive
• State = 1: Open valve completely
• State = 2: Close valve completely
GetTransitTime.State INT 0
• State = 3: Move valve to target position (New-
Output)
• State = 4: Transition time measurement suc-
cessfully completed
• State = 5: Transition time measurement can-
celed
Target position for transition time measurement
with position feedback
GetTransitTime.New- The target position must be between "High end-
REAL 0.0
Output stop" and "Low endstop". The difference be-
tween NewOutput and ScaledFeedback must be
at least 50% of the permissible control range.
If StartEstimation = TRUE, the measurement of
CycleTime.StartEsti- the PID_3Step sampling time is started. Cycle-
BOOL TRUE
mation Time.StartEstimation = FALSE once measure-
ment is complete.
If EnEstimation = TRUE, the PID_3Step sam-
pling time is calculated.
CycleTime.EnEstima- If CycleTime.EnEstimation = FALSE, the
BOOL TRUE
tion PID_3Step sampling time is not calculated and
you need to correct the configuration of Cycle-
Time.Value manually.
If EnMonitoring = TRUE, the PID_3Step sam-
pling time is monitored. If it is not possible to ex-
ecute PID_3Step within the sampling time, the
error 0800h is output and the operating mode is
CycleTime.EnMonitor- switched. ActivateRecoverMode and ErrorBeha-
BOOL TRUE
ing viour determine which operating mode is switch-
ed to.
If EnMonitoring = FALSE, the PID_3Step sam-
pling time is not monitored, the error 0800h is

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

not output, and the operating mode is not

switched.
PID_3Step sampling time in seconds

CycleTime.Value(1) REAL 0.1 CycleTime.Value is determined automatically

and is usually equivalent to the cycle time of the
calling OB.
Saved value of Retain.CtrlParams.SetByUser
CtrlParamsBack- FALS
BOOL You can reload values from the CtrlParamsBack-
Up.SetByUser E
Up structure with LoadBackUp = TRUE.
CtrlParamsBack-
REAL 1.0 Saved proportional gain
Up.Gain
CtrlParamsBackUp.Ti REAL 20.0 Saved integration time in seconds
CtrlParamsBack-
REAL 0.0 Saved derivative action time in seconds
Up.Td
CtrlParamsBack-
REAL 0.2 Saved derivative delay coefficient
Up.TdFiltRatio
CtrlParamsBack-
REAL 1.0 Saved proportional action weighting
Up.PWeighting
CtrlParamsBack-
REAL 1.0 Saved derivative action weighting
Up.DWeighting
CtrlParamsBack- Saved sampling time of PID algorithm in sec-
REAL 1.0
Up.Cycle onds
CtrlParamsBack-
REAL 0.0 Saved deadzone width of the control deviation
Up.InputDeadBand
The properties of the controlled system are
saved during tuning. If CalculateParams =
PIDSelf- TRUE, the PID parameters are recalculated on
FALS
Tune.SUT.Calculate- BOOL the basis of these properties. The PID parame-
E
Params ters are calculated using the method set in Tu-
neRule. CalculateParams is set to FALSE follow-
ing calculation.
Methods used to calculate parameters during
pretuning:
• SUT.TuneRule = 0: PID fast I (faster control
response with higher amplitudes of the output
value than with SUT.TuneRule =1)
• SUT.TuneRule = 1: PID slow I (slower control
response with lower amplitudes of the output
value than with SUT.TuneRule = 0)
PIDSelfTune.SUT.Tu-
neRule
INT 1 • SUT.TuneRule = 2: Chien, Hrones and Res-
wick PID
• SUT.TuneRule = 3: Chien, Hrones, Reswick PI
• SUT.TuneRule = 4: PID fast II (faster control
response with higher amplitudes of the output
value than with SUT.TuneRule = 5)
• SUT.TuneRule = 5: PID slow II (slower control
response with lower amplitudes of the output
value than with SUT.TuneRule = 4)

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

The methods SUT.TuneRule = 0 and 1 differ

from the methods SUT.TuneRule = 4 and 5 only
in the calculation of the proportional gain:
When SUT.TuneRule = 0 and 1, the proportional
gain is calculated based on the compensation
time of the process. When SUT.TuneRule = 4
and 5, this happens based on the delay time of
the process.
SUT.TuneRule = 4 and 5 returns a higher value
for the proportional gain and thus a faster control
response with higher amplitudes of the output
value than with SUT.TuneRule = 0 and 1.
The SUT.State tag indicates the current phase of
pretuning:
• State = 0: Initialize pretuning
• State = 50: Determine start position without
position feedback
PIDSelf-
Tune.SUT.State
INT 0 • State = 100: Calculate the standard deviation
• State = 200: Find the point of inflection
• State = 300: Determine the rise time
• State = 9900: Pretuning successful
• State = 1: Pretuning not successful
With the RunIn tag, you can specify that fine tun-
ing can also be performed without pretuning.
• RunIn = FALSE
Pretuning is started when fine tuning is started
from inactive or manual mode.
If fine tuning is started from automatic mode,
the system uses the existing PID parameters
to control to the setpoint.
PIDSelf- FALS Only then will fine tuning start. If pretuning is
BOOL
Tune.TIR.RunIn E not possible, PID_3Step switches to the mode
from which tuning was started.
• RunIn = TRUE
The pretuning is skipped. PID_3Step attempts
to reach the setpoint with the minimum or
maximum output value. This can produce in-
creased overshoot. Only then will fine tuning
start.
RunIn is set to FALSE after fine tuning.
The properties of the controlled system are
saved during tuning. If CalculateParams =
TRUE, the PID parameters are recalculated on
PIDSelfTune.TIR.Cal- FALS
BOOL the basis of these properties. The PID parame-
culateParams E
ters are calculated using the method set in Tu-
neRule. CalculateParams is set to FALSE follow-
ing calculation.

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

Methods used to calculate parameters during

fine tuning:
• TIR.TuneRule = 0: PID automatic
• TIR.TuneRule = 1: PID fast (faster control re-
sponse with higher amplitudes of the output
value than with TIR.TuneRule = 2)
• TIR.TuneRule = 2: PID slow (slower control
response with lower amplitudes of the output
value than with TIR.TuneRule = 1)
• TIR.TuneRule = 3: Ziegler-Nichols PID
PIDSelfTune.TIR.Tu-
INT 0 • TIR.TuneRule = 4: Ziegler-Nichols PI
neRule
• TIR.TuneRule = 5: Ziegler-Nichols P
To be able to repeat the calculation of the PID
parameters with TIR.CalculateParams and
TIR.TuneRule = 0, 1 or 2, the previous fine tun-
ing also has to have been executed with TIR.Tu-
neRule = 0, 1 or 2.
If this is not the case, TIR.TuneRule = 3 is used.
The recalculation of the PID parameters with
TIR.CalculateParams and TIR.TuneRule = 3, 4
or 5 is always possible.
The TIR.State tag indicates the current phase of
fine tuning:
• State = -100 Fine tuning is not possible. Pre-
tuning will be performed first.
• State = 0: Initialize fine tuning
• State = 200: Calculate the standard deviation
PIDSelf- • State = 300: Attempt to reach the setpoint with
INT 0 the maximum or minimum output value
Tune.TIR.State
• State = 400: Attempt to reach the setpoint with
existing PID parameters (if pretuning was suc-
cessful)
• State = 500: Determine oscillation and calcu-
late parameters
• State = 9900: Fine tuning successful
• State = 1: Fine tuning not successful
Motor transition time in seconds
Time in seconds the actuating drive requires to
Retain.TransitTime(1) REAL 30.0 move the valve from the closed to the opened
state.
TransitTime is retentive.
If SetByUser = FALSE, the PID parameters are
determined automatically and PID_3Step oper-
Retain.CtrlPar- ates with a dead zone at the output value. The
FALS
BOOL deadzone width is calculated during tuning on
ams.SetByUser(1) E
the basis of the standard deviation of the output
value and saved in Retain.CtrlParams.Output-
DeadBand.

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

If SetByUser = TRUE, the PID parameters are

entered manually and PID_3 Step operates with-
out a dead zone at the output value. Re-
tain.CtrlParams.OutputDeadBand = 0.0
SetByUser is retentive.
Active proportional gain
To invert the control logic, use the Config.Inver-
tControl tag. Negative values at Gain also invert
Retain.CtrlPar- the control logic. We recommend you use only
REAL 1.0
ams.Gain(1) InvertControl to set the control logic. The control
logic is also inverted if InvertControl = TRUE and
Gain < 0.0.
Gain is retentive.
• Ti > 0.0: Active integration time in seconds
Retain.CtrlPar-
REAL 20.0 • Ti = 0.0: Integral action is deactivated
ams.Ti(1)
Ti is retentive.
• Td > 0.0: Active derivative action time in sec-
onds
Retain.CtrlPar-
ams.Td(1)
REAL 0.0 • Td = 0.0: Derivative action is deactivated
Td is retentive.
Active derivative delay coefficient
The derivative delay coefficient delays the effect
of the derivative action.
Derivative delay = derivative action time × deriv-
ative delay coefficient
Retain.CtrlPar- • 0.0: Derivative action is effective for one cycle
REAL 0.2 only and therefore almost not effective.
ams.TdFiltRatio(1)
• 0.5: This value has proved useful in practice
for controlled systems with one dominant time
constant.
• > 1.0: The greater the coefficient, the longer
the effect of the derivative action is delayed.
TdFiltRatio is retentive.
Active proportional action weighting
The proportional action may weaken with
changes to the setpoint.
Values from 0.0 to 1.0 are applicable.
Retain.CtrlPar- • 1.0: Proportional action for setpoint change is
REAL 1.0 fully effective
ams.PWeighting(1)
• 0.0: Proportional action for setpoint change is
not effective
The proportional action is always fully effective
when the process value is changed.
PWeighting is retentive.
Retain.CtrlPar-
REAL 1.0 Active derivative action weighting
ams.DWeighting(1)

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 Static tags of PID_3Step V2 (S7-1200, S7-1500)

The derivative action may weaken with changes

to the setpoint.
Values from 0.0 to 1.0 are applicable.
• 1.0: Derivative action is fully effective upon
setpoint change
• 0.0: Derivative action is not effective upon set-
point change
The derivative action is always fully effective
when the process value is changed.
DWeighting is retentive.
Active sampling time of PID algorithm in sec-
Retain.CtrlPar- onds, rounded to an integer multiple of the cycle
REAL 1.0 time of the calling OB.
ams.Cycle(1)
Cycle is retentive.
Retain.CtrlParams.In- Deadzone width of the control deviation
REAL 0.0
putDeadBand(1) InputDeadBand is retentive.

See also
Parameters State and Mode V2 (S7-1200, S7-1500)
Tag Warning V2 (S7-1200, S7-1500)
Tag ActivateRecoverMode V2 (S7-1200, S7-1500)
Downloading technology objects to device

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