From regulation basics to advanced control

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From regulation basics to advanced control
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Overview

• Regulation what is a control loop?
• What is a PID controller?
• What is advanced control?
• Identifying, Modeling . Tuning
• Advanced control example predictive control
• Schneider tool for Modeling and Tuning available
  in ITCO
• Application for GCS MultiController

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Regulation what is a control loop?

• I want to see a measured value which corresponds
  to my request

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Regulation what is a control loop?
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Regulation what is a control loop?

• Control Loop system Representation
• Example Open Loop representation

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Regulation what is a control loop?

• Control Loop system Representation
• Example Closed Loop representation

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G(p)
Desired Temperature (SP, 150C)
C(p)
Acts on heating power (u, 4-20mA)
Reaction The water temperature reacts on heating
power changes
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What is a PID controller?

• PID means Proportional, Derivative Integrative.
• In a classic control loop system, the PID is the
  controller placed before the process

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What is a PID controller?

• PID Elementary actions
• Proportional

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What is a PID controller?

• PID Elementary actions
• Integrative
• Ti is the coefficient given to increase or
  decrease the integrative action

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What is a PID controller?

• PID Elementary actions
• Derivative
• Td is the coefficient given to increase or
  decrease the derivative action

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What is a PID controller?

• PID Elementary actions
• Sum up

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What is advanced control?
Advanced Control - Sébastien Cabaret 9 Feb. 2006
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Identifying, Modeling Tuning

• Process to tune a controller
• We should have the knowledge of the system
• We should give information to the controller for
  its tuning

Controller parameters TUNING Ex P,I and D for
PID
System information
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Advanced control example predictive control

• The predictive control method is an advanced
  control strategy
• It is a good compromise between performance and
  complexity
• It is based on a model for the prediction of the
  process output and on a determinate horizon
• It also uses a reference trajectory to attempt
  the desire response
• Several predictive controls exist due to various
  mathematical approaches of automation people.

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The predictive control is closed to human driver
behavior
The controller contains the model of the process
to drive
The driver has built a mental picture of its
car behaviors
He knows the efficiency of the brakes and knows
the effect to his car
The model allows to predict the effect of the
action to the system output
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Predictive Control

• The model used by the controller is a dynamic
  representation of the input/output relationships
  (ex mental model of the car vs. the road)
• The reference trajectory is known by the
  controller (ex car trajectory)
• The horizon definition is specified (ex 20
  seconds)

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Model
Set Point
Horizon
Real trajectory
Reference trajectory
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Future
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Schneider tool for Modeling and Tuning available
in ITCO
DataStore
Optireg

• Some predictive
• algorithms
• PID

• Schneider PLC

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Application MultiController object in GCS project
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Application MultiController object in GCS project
Smith Predictor
IF1
MultiController

• The MultiController is a standard UNICOS object
  for Schneider PLC and PVSS SCADA system
• Replace UNICOS PID controller
• UNICOS compatible (modes, connection, hierarchy)
• It has a single interface for all regulation
  algorithms
• The design allows the addition of new control
  loop algorithms without changing the object
  interface
• It has been design to offer a recipe mechanism.
  It allows the process expert to keep and reuse
  pertinent sets of tuning parameters

PID
RST
PFC generalized
SF1
DC3
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Application MultiController object in GCS project

• The MultiController is a standard UNICOS object
  for Schneider PLC and PVSS SCADA system
• It has a unique Human Machine Interface with
  different views
• It is composed of a synoptic, trend views,
  navigation buttons
• It allows a global control of the regulation loop
  via a centralized object representation in the
  HMI with different views

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MultiController operation under PVSS
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MultiController future application adaptive
control
System to control
Online Model Identification under PLC
GPC tuning Mechanism in PLC (Predictive strategy)
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Advanced Control

• Questions