Siemens SIMATIC S7-1200 Function Manual page 303

● Startup characteristics
The operating mode specified at the Mode parameter is also started on a negative edge
at Reset and during a CPU cold restart, if RunModeByStartup = TRUE.
● ENO characteristics
ENO is set depending on the operating mode.
If State = 0, then ENO = FALSE.
If State ≠ 0, then ENO = TRUE.
● Manual mode
The Manual_UP and Manual_DN input parameters no longer function as edge-triggered
parameters. Edge-triggered manual mode continues to be possible using the
ManualUpInternal and ManualDnInternal tags.
In "Manual mode without endstop signals" (Mode = 10), the endstop signals Actuator_H
and Actuator_L are ignored even though they are activated.
● Default value of PID parameters
The following default settings have been changed:
– Proportional action weighting (PWeighting) from 0.0 to 1.0
– Derivative action weighting (DWeighting) from 0.0 to 1.0
– Coefficient for derivative delay (TdFiltRatio) from 0.0 to 0.2
● Limiting of motor transition time
You configure the maximum percentage of the motor transition time that the actuator will
travel in one direction in the Config.VirtualActuatorLimit tag.
● Setpoint value specification during tuning
You configure the permitted fluctuation of the setpoint during tuning at the
CancelTuningLevel tag.
● Switching a disturbance variable on
You can switch a disturbance variable on at the Disturbance parameter.
● Troubleshooting
If the endstop signals are not activated (ActuatorEndStopOn = FALSE), ScaledFeedback
is determined without Actuator_H or Actuator_L.
PID_3Step V1.1
● Manual mode on CPU startup
If ManualEnable = TRUE when the CPU starts, PID_3Step starts in manual mode. A
positive edge at ManualEnable is not necessary.
● Reaction to error
The ActivateRecoverMode tag is no longer effective in manual mode.
● Troubleshooting
The Progress tag is reset following successful tuning or transition time measurement.
PID control
Function Manual, 03/2017, A5E35300227-AC
Instructions
9.2 PID_3Step
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