(19)
(11)EP 3 161 562 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
20.05.2020 Bulletin 2020/21

(21)Application number: 15734470.6

(22)Date of filing:  25.06.2015
(51)Int. Cl.: 
G05B 9/03  (2006.01)
G05B 19/042  (2006.01)
G05B 17/02  (2006.01)
G05B 19/418  (2006.01)
(86)International application number:
PCT/IB2015/054769
(87)International publication number:
WO 2015/198256 (30.12.2015 Gazette  2015/52)

(54)

A METHOD FOR CONTROLLING A PROCESS PLANT USING A REDUNDANT LOCAL SUPERVISORY CONTROLLER

VERFAHREN ZUR STEUERUNG EINER PROZESSANLAGE MIT EINEM REDUNDANTEN LOKALEN ÜBERWACHUNGSSTEUERGERÄT

PROCÉDÉ DE COMMANDE D'UNE INSTALLATION DE TRAITEMENT AU MOYEN D'UN CONTRÔLEUR DE SUPERVISION LOCAL REDONDANT


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 26.06.2014 IN 3099CH2014

(43)Date of publication of application:
03.05.2017 Bulletin 2017/18

(73)Proprietor: ABB Schweiz AG
5400 Baden (CH)

(72)Inventors:
  • BHAT, Shrikant
    Nagpur 440015 (IN)
  • LUNDH, Michael
    S-72349 Vasteras (SE)

(74)Representative: Zimmermann & Partner Patentanwälte mbB 
Josephspitalstr. 15
80331 München
80331 München (DE)


(56)References cited: : 
EP-A1- 2 293 159
US-A1- 2007 142 936
US-A1- 2005 004 684
US-A1- 2013 285 799
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    FIELD OF INVENTION



    [0001] The present invention relates to control systems and industrial automation. More particularly, the present invention relates to redundant secondary controllers of control systems.

    BACKGROUND



    [0002] In automation context, advanced process control applications are control applications supervise and regulate the local control applications. Advanced process control applications, due to their high processing requirements, are present on remote servers and communicate with the local control applications within the plant site in terms of assigning the set-points to the local control applications. The local control applications targets to attain the received set points. For example, a model predictive control assigns set-point to the plant level PID control and PID controller targets to attain that.

    [0003] Usually advanced process control applications involve use of model, control, optimization, analytical computations, etc., with different levels of complexity and often require an expert support. While shifting advanced applications to a cloud platform or a remote computing platform, the computational complexity and expertise stays with the cloud platform, and only the optimal set points are communicated to the plant level local control applications. In case of failure of connectivity to the cloud platform, or any other issues that prevent communication between the advanced process control application and the local control application, the local control application keeps operating at the previously assigned set-points from the advanced control application.

    [0004] Conventionally, one approach to handle loss of connectivity between the cloud platform and the local control application, a backup or redundant network access point having similar functionality as the advanced control application is provided. Upon detection of loss of connectivity, the redundant network access point is selected to act as the advanced control application. In another approach, a secondary communication channel is present between the cloud platform and the local control application. The advanced control application is accessed through the secondary communication channel upon failure of the primary communication channel.

    [0005] US 2005/0004684 A1 relates to a system and a method for adjusting a control model, wherein control information is received from a sensor. In US 2013/0285799 A1, a cloud-hosted control system for protecting against local control failure is described. A process control system that integrates the collection and analysis of process control data is presented in US 2007/0142936 A1.

    [0006] However, these approaches involve considerable costs. Therefore, there is a need for an improved method and system which is capable of handling loss of connectivity between the advanced control processes on the cloud platform and the local control infrastructure present in the plant

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0007] 

    Figure 1 illustrates a system for controlling a process using a plurality of field devices in a process plant, in accordance with various embodiments of the present invention; and

    Figure 2 illustrates a method for controlling a process using a plurality of field devices in a process plant, in accordance with various embodiments of the present invention.


    DETAILED DESCRIPTION OF THE INVENTION



    [0008] In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments, which may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments, and it is to be understood that other embodiments may be utilized and that logical, mechanical, electrical and other changes may be made without departing from the scope of the embodiments. The following detailed description is, therefore, not to be taken in a limiting sense.

    [0009] Figure 1 illustrates a system 100 controlling a process using a plurality of field devices (not shown in figure 1) in a process plant 150. The plurality of field devices includes one or more sensors located in various areas of the process plant for measuring process variables associated with the process. These process variables are herein referred to as measured process variables. Additionally, the plurality of field devices includes one or more actuators which regulate various physical parameters in relation to the process.

    [0010] The plurality of field devices including the sensors and the field devices are operatively connected to a plurality of corresponding regulatory controllers 160 (illustrated in figure to as controller 163 and controller 166), thereby forming one or more control loops. The regulatory controllers 160, on the basis of set points in relation to certain process variables (herein after referred to as control variables) and the measurements from the sensors, regulate the actuators accordingly. The regulatory controllers 160 receive set points in relation to the one or more control variables from a remote supervisory controller 120 during normal mode of operation.

    [0011] The remote supervisory controller 120 is located outside the process plant 150. The remote supervisory controller 120 is connected to the plurality of regulatory controllers 160 via a communication link 155. The remote supervisory controller 120 receives information associated with one or more measured process variables, and generates one or more set points in relation to one or more control process variables, using a remote process model based on the information associated with the one or more measured process variables. In an embodiment, the remote supervisory controller 120 is hosted as a service on a remote computing platform 110.

    [0012] Additionally, the system 100 includes a local supervisory controller 130 connected to the plurality of regulatory controllers 160 over a process bus 170 of a control network within the process plant 150. The local supervisory controller 130 includes a local process model (not shown in figure 1). The local process model of the local supervisory controller 130 is configured by a configuration server 125. Upon an intermediate or temporary failure of communication link 155, the local supervisory controller 130 using the configured local process model, provides intermediate set points to the plurality of regulatory controller 160 till the communication link 155 is recovered and connection with the remote supervisory controller 120 is reestablished. The local supervisory controller 130 works a temporary back up for the remote supervisory controller 120 till the communication link 155 recovers from the intermediate failure. These aspects are further explained in the description of figure 2.

    [0013] Figure 2 illustrates a method 200 for controlling a process using a plurality of field devices in the process plant 150, in accordance with various embodiments of the present invention.

    [0014] At step 210, the configuration server monitors transmission of the information associated with one or more measured process variables, and the one or more set points in relation to one or more control process variables;

    [0015] Figure 2 illustrates a method 200 of assisting a first operator using the operator assistance tool during one or more engineering activities including configuration of a plurality of devices (115, 117 and 119), in accordance with various embodiments of the present invention.

    [0016] At step 210, the configuration server 125 monitors transmission of control data between the remote supervisory controller 120 and the plurality of controllers 160 over the communication link 155. The control data herein refers to information associated with one or more measured process variables, and one or more set points in relation to one or more control process variables, generated using the remote process model based on the information associated with the one or more measured process variables.

    [0017] At step 220, the configuration server 125 determines one or more functional correlations between the one or more measured process variables and the one or more control process variables, based on the control data and a predetermined correlation function. The configuration server 125 utilizes a plurality of statistical methods commonly known in the art to determine one or more functional correlations between the one or more measured process variables and the one or more control process variables. For example, if the configuration server 125 identifies from the control data that violation of a measured process variable results in new set points in relation to control process variable, the configuration server 125 determines that a functional correlation exists between the measured process variable and the control process variable. Particularly, using the remote supervisory controller and the control data, the configuration server 125 identifies the one or more control variables for which new set points are generated when certain measured process variables violate process constraints. Accordingly, the configuration server 125 determines functional correlations between the control variables and measured variables.

    [0018] Similarly in an embodiment, when the number of measured variables is more than the number of control variables or vice versa, the configuration server 125 determines the significance of each control variable on a measured variable.

    [0019] At step 230, the configuration server 125 configures the local process model based on the determined one or more functional correlations. In an embodiment, the configuration server 125 configures the local process model in accordance with the significance of each control process variable on a measured process variable. Upon the intermediate or temporary failure of the communication link 155, at step 240, the local supervisory controller provides one or more intermediate set points in relation to the one or more control process variables using the configured local process model, to the plurality of controllers 160 for regulating the one or more field devices.

    [0020] The communication link 155 recovers from the intermediate failure within a predetermined time period. In an embodiment, the predetermined time period is set by an operator of the process plant 150. In an embodiment, if the communication link 155 does not recover within the predetermined period of time, the local supervisory controller 130 raises an alarm. In an embodiment, the configuration server 125 keeps tuning and updating the functional correlations and accordingly configures the local supervisory controller.

    [0021] .This written description uses examples to describe the subject matter herein, including the best mode, and also to enable any person skilled in the art to make and use the subject matter. The patentable scope of the subject matter is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.


    Claims

    1. A method for controlling a process with a plurality of field devices in a process plant (150) using a plurality of regulatory controllers (160), wherein the plurality of regulatory controllers (160) are connected to a remote supervisory controller (120) over a communication link (155) and to a local supervisory controller (130) over a process bus (170) for receiving set points, the method comprising

    a. monitoring transmission of control data between the remote supervisory controller (120) and the plurality of controllers (160) over the communication link (155), wherein the control data includes information associated with one or more measured process variables, and one or more set points in relation to one or more control process variables, generated by the remote supervisory controller (120) using a remote process model based on the information associated with the one or more measured process variables;

    b. determining one or more functional correlations between the one or more measured process variables and the one or more control process variables, based on the control data and a predetermined correlation function for configuring a local process model of the local supervisory controller;

    c. configuring the local process model based on the determined one or more functional correlations; and

    d. providing one or more intermediate set points in relation to the one or more control process variables using the configured local process model, to the plurality of controllers (160) for regulating the one or more field devices, upon an intermediate failure of the communication link (155);
    wherein the communication link (155) recovers from the intermediate failure within a predetermined time period.


     
    2. The method as claimed in claim 1, wherein the plurality of regulatory controller (160) includes one or more proportional integrative derivative (PID) controllers.
     
    3. The method as claimed in claim 1, wherein the predetermined correlation function is set in the remote supervisory controller (120).
     
    4. The method as claimed in claim 1, wherein the local process model is a linear process model.
     
    5. A system for controlling a process using a plurality of field devices in a process plant (150), the system comprising

    a. a plurality of regulatory controllers (160) for regulating the plurality of field devices of the process plant (150), wherein the plurality of the regulatory controllers (160) are connected to a local supervisory controller (130) over a process bus of a control network in the process plant;

    b. a remote supervisory controller (120) connected to the plurality of regulatory controllers (160) via a communication link (155) for receiving information associated with one or more measured process variables, and for generating and transmitting one or more set points in relation to one or more control process variables, using a remote process model based on the information associated with the one or more measured process variables; and

    c. wherein the local supervisory controller (130) is configured to

    i. provide one or more intermediate set points in relation to the one or more control process variables using a local process model, to the plurality of controllers (160) for regulating the one or more field devices, upon an intermediate failure of the communication link (155); and

    d. a configuration server (125) connected to the remote supervisory controller, configured to

    i. monitor transmission of control data between the remote supervisory controller (120) and the plurality of controllers (160) via the communication link (155), wherein the control data includes the information associated with one or more measured process variables, and the one or more set points in relation to one or more control process variables;

    ii. determine one or more functional correlations between the one or more measured process variables and the one or more control process variables based on the control data and a predetermined correlation function; and

    iii. configure the local process model based on the determined one or more functional correlations; and

    wherein the communication link (155) recovers from the intermediate failure within a predetermined time period.


     
    6. The system as claimed in claim 5, wherein the plurality of regulatory controller (160) includes one or more proportional integrative derivative (PID) controllers.
     
    7. The system as claimed in claim 5, wherein the predetermined correlation function is set in the remote supervisory controller (120).
     
    8. The system as claimed in claim 5, wherein the local process model is a linear process model.
     


    Ansprüche

    1. Verfahren zur Steuerung eines Prozesses mit mehreren Feldvorrichtungen in einer Prozessanlage (150) unter Verwendung von mehreren Regelungssteuergeräten (160), wobei die mehreren Regelungssteuergeräte (160) über eine Kommunikationsverbindung (155) mit einem entfernten Überwachungssteuergerät (120) und über einen Prozessbus (170) zum Empfangen von Einstellpunkten mit einem lokalen Überwachungssteuergerät (130) verbunden sind, wobei das Verfahren Folgendes umfasst:

    a. Überwachen der Übertragung von Steuerungsdaten zwischen dem entfernten Überwachungssteuergerät (120) und den mehreren Steuergeräten (160) über die Kommunikationsverbindung (155), wobei die Steuerungsdaten Informationen in Verbindung mit einer oder mehreren gemessenen Prozessvariablen und einem oder mehreren Einstellpunkten in Beziehung zu einer oder mehreren Steuerungsprozessvariablen umfassen, erzeugt durch das entfernte Überwachungssteuergerät (120) unter Verwendung eines entfernten Prozessmodells basierend auf den Informationen in Verbindung mit der einen oder den mehreren gemessenen Prozessvariablen;

    b. Bestimmen von einer oder mehreren funktionalen Korrelationen zwischen der einen oder den mehreren gemessenen Prozessvariablen und der einen oder den mehreren Steuerungsprozessvariablen, basierend auf den Steuerungsdaten und einer vorbestimmten Korrelationsfunktion zum Auslegen eines lokalen Prozessmodells des lokalen Überwachungssteuergeräts;

    c. Auslegen des lokalen Prozessmodells basierend auf der bzw. den bestimmten einen oder mehreren funktionalen Korrelationen; und

    d. Bereitstellen von einem oder mehreren Zwischeneinstellpunkten in Beziehung zu der einen bzw. den mehreren Steuerungsprozessvariablen unter Verwendung des ausgelegten lokalen Prozessmodells, für die mehreren Steuergeräte (160) zum Regeln der einen oder mehreren Feldvorrichtungen, bei einem zwischenzeitlichen Ausfall der Kommunikationsverbindung (155); wobei sich die Kommunikationsverbindung (155) von dem zwischenzeitlichen Ausfall innerhalb eines vorbestimmten Zeitraums erholt.


     
    2. Verfahren nach Anspruch 1, wobei die mehreren Regelungssteuergeräte (160) ein oder mehrere Proportional-Integrier-Differenzier-Steuergeräte (PID) umfassen.
     
    3. Verfahren nach Anspruch 1, wobei die vorbestimmte Korrelationsfunktion im entfernten Überwachungssteuergerät (120) festgelegt wird.
     
    4. Verfahren nach Anspruch 1, wobei das lokale Prozessmodell ein lineares Prozessmodell ist.
     
    5. System zur Steuerung eines Prozesses unter Verwendung mehrerer Feldvorrichtungen in einer Prozessanlage (150), wobei das System Folgendes umfasst:

    a. mehrere Regelungssteuergeräte (160) zum Regeln der mehreren Feldvorrichtungen der Prozessanlage (150), wobei die mehreren Regelungssteuergeräte (160) über einen Prozessbus eines Steuerungsnetzwerks in der Prozessanlage mit einem lokalen Überwachungssteuergerät (130) verbunden sind;

    b. ein entferntes Überwachungssteuergerät (120), das mit den mehreren Regelungssteuergeräten (160) über eine Kommunikationsverbindung (155) verbunden ist, zum Empfangen von Informationen in Verbindung mit einer oder mehreren gemessenen Prozessvariablen und zum Erzeugen und Senden von einem oder mehreren Einstellpunkten in Beziehung zu einer oder mehreren Steuerungsprozessvariablen unter Verwendung eines entfernten Prozessmodells basierend auf den Informationen in Verbindung mit der einen oder den mehreren gemessenen Prozessvariablen; und

    c. wobei das lokale Überwachungssteuergerät (130) ausgelegt ist zum

    i. Bereitstellen von einem oder mehreren Zwischeneinstellpunkten in Beziehung zu der einen bzw. den mehreren Steuerungsprozessvariablen unter Verwendung eines lokalen Prozessmodells, für die mehreren Steuergeräte (160) zum Regeln der einen oder mehreren Feldvorrichtungen, bei einem zwischenzeitlichen Ausfall der Kommunikationsverbindung (155); und

    d. einen Auslegungsserver (125), der mit dem entfernten Überwachungssteuergerät verbunden ist, ausgelegt zum

    i. Überwachen der Übertragung von Steuerungsdaten zwischen dem entfernten Überwachungssteuergerät (120) und den mehreren Steuergeräten (160) über die Kommunikationsverbindung (155), wobei die Steuerungsdaten Informationen in Verbindung mit einer oder mehreren gemessenen Prozessvariablen und dem einen oder den mehreren Einstellpunkten in Beziehung zu einer oder mehreren Steuerungsprozessvariablen umfassen;

    ii. Bestimmen von einer oder mehreren funktionalen Korrelationen zwischen der einen oder den mehreren gemessenen Prozessvariablen und der einen oder den mehreren Steuerungsprozessvariablen, basierend auf den Steuerungsdaten und einer vorbestimmten Korrelationsfunktion; und

    iii. Auslegen des lokalen Prozessmodells basierend auf der einen oder den mehreren bestimmten Korrelationen; und wobei sich die Kommunikationsverbindung (155) innerhalb eines vorbestimmten Zeitraums von dem zwischenzeitlichen Ausfall erholt.


     
    6. System nach Anspruch 5, wobei die mehreren Regelungssteuergeräte (160) ein oder mehrere Proportional-Integrier-Differenzier-Steuergeräte (PID) umfassen.
     
    7. System nach Anspruch 5, wobei die vorbestimmte Korrelationsfunktion im entfernten Überwachungssteuergerät (120) festgelegt wird.
     
    8. System nach Anspruch 5, wobei das lokale Prozessmodell ein lineares Prozessmodell ist.
     


    Revendications

    1. Procédé de contrôle d'un processus avec une pluralité de dispositifs de terrain dans une installation de processus (150) au moyen d'une pluralité de contrôleurs de régulation (160), la pluralité de contrôleurs de régulation (160) étant connectés à un contrôleur de supervision distant (120) sur une liaison de communication (155) et à un contrôleur de supervision local (130) sur un bus de processus (170) pour recevoir des points de consigne, le procédé comprenant les étapes consistant à :

    a. surveiller une transmission de données de contrôle entre le contrôleur de supervision distant (120) et la pluralité de contrôleurs (160) sur la liaison de communication (155), les données de contrôle incluant une information associée à une ou plusieurs variables de processus mesurées ainsi qu'un ou plusieurs points de consigne en relation avec une ou plusieurs variables de processus de contrôle, générés par le contrôleur de supervision distant (120) au moyen d'un modèle de processus distant sur la base de l'information associée à la ou aux variables de processus mesurées ;

    b. déterminer une ou plusieurs corrélations fonctionnelles entre la ou les variables de processus mesurées et la ou les variables de processus de contrôle, sur la base des données de contrôle et d'une fonction de corrélation prédéterminée pour configurer un modèle de processus local du contrôleur de supervision local ;

    c. configurer le modèle de processus local sur la base de la ou des corrélations fonctionnelles déterminées ; et

    d. fournir à la pluralité de contrôleurs (160) un ou plusieurs points de consigne intermédiaires en relation avec la ou les variables de processus de contrôle au moyen du modèle de processus local configuré pour réguler le ou les dispositifs de terrain, en cas de panne intermédiaire de la liaison de communication (155) ;
    la liaison de communication (155) se remettant de la panne intermédiaire pendant une période de temps prédéterminée.


     
    2. Procédé selon la revendication 1, dans lequel la pluralité de contrôleurs de régulation (160) inclut un ou plusieurs contrôleurs proportionnels, par intégration et par dérivation (PID).
     
    3. Procédé selon la revendication 1, dans lequel la fonction de corrélation prédéterminée est définie dans le contrôleur de supervision distant (120).
     
    4. Procédé selon la revendication 1, dans lequel le modèle de processus local est un modèle de processus linéaire.
     
    5. Système de contrôle d'un processus au moyen d'une pluralité de dispositifs de terrain dans une installation de processus (150), le système comprenant :

    a. une pluralité de contrôleurs de régulation (160) pour réguler la pluralité de dispositifs de terrain de l'installation de processus (150), la pluralité des contrôleurs de régulation (160) étant connectés à un contrôleur de supervision local (130) sur un bus de processus d'un réseau de contrôle dans l'installation de processus ;

    b. un contrôleur de supervision distant (120) connecté à la pluralité de contrôleurs de régulation (160) par l'intermédiaire d'une liaison de communication (155) pour recevoir une information associée à une ou plusieurs variables de processus mesurées et pour générer et transmettre un ou plusieurs points de consigne en relation avec une ou plusieurs variables de processus de contrôle, au moyen d'un modèle de processus distant sur la base de l'information associée à la ou aux variables de processus mesurées ; et

    c. le contrôleur de supervision local (130) étant configuré pour :

    i. fournir à la pluralité de contrôleurs (160) un ou plusieurs points de consigne intermédiaires en relation avec la ou les variables de processus de contrôle au moyen d'un modèle de processus local pour réguler le ou les dispositifs de terrain, en cas de panne intermédiaire de la liaison de communication (155) ; et

    d. un serveur de configuration (125) connecté au contrôleur de supervision distant, configuré pour :

    i. surveiller une transmission de données de contrôle entre le contrôleur de supervision distant (120) et la pluralité de contrôleurs (160) par l'intermédiaire de la liaison de communication (155), les données de contrôle incluant l'information associée à une ou plusieurs variables de processus mesurées ainsi que le ou les points de consigne en relation avec une ou plusieurs variables de processus de contrôle ;

    ii. déterminer une ou plusieurs corrélations fonctionnelles entre la ou les variables de processus mesurées et la ou les variables de processus de contrôle, sur la base des données de contrôle et d'une fonction de corrélation prédéterminée ; et

    iii. configurer le modèle de processus local sur la base de la ou des corrélations fonctionnelles déterminées ; et
    la liaison de communication (155) se remettant de la panne intermédiaire pendant une période de temps prédéterminée.


     
    6. Système selon la revendication 5, dans lequel la pluralité de contrôleurs de régulation (160) inclut un ou plusieurs contrôleurs proportionnels, par intégration et par dérivation (PID).
     
    7. Système selon la revendication 5, dans lequel la fonction de corrélation prédéterminée est définie dans le contrôleur de supervision distant (120).
     
    8. Système selon la revendication 5, dans lequel le modèle de processus local est un modèle de processus linéaire.
     




    Drawing









    REFERENCES CITED IN THE DESCRIPTION



    This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

    Patent documents cited in the description