WO2008155597A1

WO2008155597A1 - Distributed computing architecture for thin-client based graphics builder for embedded industrial controllers

Info

Publication number: WO2008155597A1
Application number: PCT/IB2007/001633
Authority: WO
Inventors: Kapaleeswaran Viswanathan; Srijith Kumar Bhadra; Pradyumna Sampath
Original assignee: Abb Research Limited
Priority date: 2007-06-18
Filing date: 2007-06-18
Publication date: 2008-12-24

Abstract

The present invention discloses a system to enable graphics building (301), which involves rendering graphics for embedded industrial controllers that are part of an automation setup using thin-client technology. The system of the present invention has several entities including a controller (303), in which a control engine (314) resides. One or more control variables, defined by the user through the control algorithm running on the control engine (314), are used to monitor, control and configure one or more embedded industrial controllers. An external web-server with a repository of graphics data (309) is used to provide input to the graphics builder (301). A thin client is a program downloaded and executed by host computer, which is not required to be resource intensive since most computing is done on the server.

Description

DISTRIBUTED COMPUTING ARCHITECTURE FOR THIN-CLIENT BASED GRAPHICS BUILDER FOR EMBEDDED INDUSTRIAL CONTROLLERS

BACKGROUND

FIELD OF THE INVENTION

This invention relates to a graphics builder for embedded industrial controllers wherein the paradigm of thin-clients is used, to enable distributed computing and control.

DISCUSSION OF PRIOR ART

Graphics Builders are tools that enable rapid prototyping of user interfaces, allowing reusability and iterative development. Several Supervisory Control And Data Acquisition (SCADA) packages, used in large-scale, distributed measurement, monitoring and control systems, typically deployed in industrial plants, are equipped with graphics builders. Since these industrial plants are comprised of several devices, controllers and other functional components, working in conjunction, graphics builders are required to provide user-interfaces to control and monitor these entities. Thin client technology typically refers to a client-server architecture wherein the clients are streamlined in order to provide for a computing paradigm wherein a bulk of the processing is done at the server. This typically implies that the clients are not required to be resource intensive in terms of computing, memory or storage capabilities. The use of thin-client technology also enables distributed and decentralized computing, which is highly desirable in a networked setup. Several web-based communication technologies including AJAX, SOAP, JNLP and XML-RPC have evolved in order to realize programming distributed and networked systems including industrial control systems. Typically, industrial control systems employ a graphics builder, which resides on a PC, while communicating with a group of controllers, via a server. The limitations of the prior art include that of requiring a resource-intensive compute substrate for the graphics builder, when several controllers try to access it. The present invention proposes the use of thin-client technology for graphics builders that are used to render the faceplates of embedded industrial controllers.

US Patent 7017116B2 discloses a Graphic Human Machine Interface on a Portable Device wherein emphasis is placed on interfacing a less powerful HMI host with a realtime process control facility via a more powerful server. US2003158975 discloses a Real time data interface and method for browsers and the like wherein a method is proposed for rendering pre-defined graphics on browsers. US2003159129 proposes a Component model for real-time system control wherein a framework for building component-based software. US2004177357 proposes a Web-based presentation of automation processes wherein thin clients and Scalable Vector Graphics (SVG) are used. This client is also related to a method of rendering pre-defined graphics on browsers, as opposed to generating graphics remotely. US6356920 proposes a Dynamic hierarchical data exchange system wherein hierarchically related elements of data, some of which have dynamic properties, which necessitate a certain series of execution to effect the production of correct results. US2005216826 proposes a Method for providing a concurrent overview and detailed display of industrial production facilities wherein a visualization technique is proposed for an industrial production facility. WO2006050529 proposes a HMI reconfiguration and system wherein control objects are exposed to the end-users via the HMI. US2Q05108364 discloses Systems and methods that utilized scalable vector graphics wherein an industrial device can be visualized via a remote Web interface with the use of SVG. This does not mention the use of thin-client technology or specifically find its use in automation environments. WO2005116823 proposes a System and method for developing animated visualization interface, which address graphic building for process control, wherein graphical symbols are aggregated with "application modules". US6976086 proposes Systems and methods to facilitate a distribution of information via a dynamically loadable component wherein the distribution of information via one or more dynamically loadable components is facilitated. US7062335 proposes an Interface to a programmable logic controller, which relates to the field of industrial automation and utilizes thin clients running on such protocols as HTTP and TCP/IP. There is no specific focus on graphics building, in this patent. US2002199123 proposes a Security architecture for a process control platform executing applications wherein different roles are assigned to the users of the system to facilitate a variety of permissions to access a set of objects within the system.

The present invention proposes an architecture that enables seamless integration of various functional components that allow for flexible, decentralized and distributed graphics building, for industrial controllers. The architecture of the present invention is web-enabled and based on thin-client technology. Further, this architecture is technology neutral and incorporates a variety of proprietary and standardized formats. The framework of the present invention proposes flexible location of various processes and data on controllers, thin clients or on various application servers, thereby removing the constraints on the physical location of the processes and associated data. Further, the present invention is equipped with security logic to guarantee authorized access to data within the system. The present invention can be used to improve the functionality of industrial controllers while simultaneously decreasing the cost associated in commissioning and installation.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a system, method and apparatus to enable graphics building, which involves rendering graphics for embedded industrial controllers that are part of an automation setup using thin-client technology. Current systems for graphics builders are based on a thick-client paradigm, wherein the client is required to perform many of the computations, consequently being resource-intensive. Besides increasing the cost for commissioning and installation, the time taken to deploy up-to- date developments in graphics and related software is increased. Control applications are in the process of migrating to web-based technologies, paving way for distributed computing. Standards such as Scalable Vector Graphics (SVG) have been introduced to enable the proliferation of distributed computing including the realm of industrial control. The system of the present invention has several entities including a controller, which is an embedded device within which a control engine resides. One ore more control variables, defined by the user in the control algorithm running on the control engine are used to monitor, control and configure one or more embedded industrial controllers. An external web-source, which is a web-server with a repository of graphics data, is used to provide input to the graphics builder. A thin client is a program that is downloaded and executed by a host program wherein the host computer is not required to be resource intensive as most of the computing is done on the server.

BRIEF DESCRIPTION OF DRAWINGS

Fig.l contrasts the systems known in the art, with the present invention. Fig. 2 shows the generic process flow for Graphics Building. Fig. 3 shows a controller centric architecture. Fig. 4 shows a thin-client centric architecture.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Fig.l contrasts the systems known in the art, with the present invention. In the existing state of the art, a group of controllers 101 interface via a set of computers 102 to a server

105, which talks to another set of computers 103 that finally communicates with a graphics builder 104 running on a PC. In the proposed art, a group of controllers 106 interfaces with one set of computers 107 that have a set of thin-clients running on them

108, 109, 110, ameliorating their requirement of resource intensity, and the set of computers 107 also interface with a graphics builder application server 111.

Fig. 2 shows the generic process flow for Graphics Building. A combination of graphic elements from. Additionally an external web source 201, which is a web-server with a repository of graphics elements 206, delivers these elements using such technologies as FTP, XML RPC, SOAP, HTTP, AJAX, and JNLP etc. as input to the graphics builder 207. Graphics elements 206 are visual representations of industrial process control systems such as valves, motor pumps etc. These elements can be represented using proprietary or standardized formats such as SVG. The Graphics Builder 207 is used to build relevant graphics, including animation graphics 208, which refer to an assembly of graphic elements 206 with animation and state transition properties. These elements can be represented using proprietary or standardized formats such as SVG, Macromedia FLASH, XAML, and GDI etc. The animation graphics 208 thus produced are input to a Control object 204 to graphics associator 209, which allows the user to map the animation and state transition properties in animation graphics 208 with elements of aggregated control objects 202. Aggregated control objects 202 refer to a representation of a group of industrial controllers that act in unison to realize an industrial control process with an industrial plant. Examples of these processes include the operation of a boiler, actuation of valves etc. Aggregated control objects 202 are a special class of control objects 204, which can be stored in proprietary or standardized formats such as XML, Oracle DB elements etc. As a result of this association, control animation graphics 210 are produced. Control animation graphics 210 are data structures that are a union of animation graphics 208 and control objects or aggregated control objects 202, such that a relationship between the graphic elements and the control objects 204 or aggregated control objects 202, exist. The control animation graphics 210 are optionally stored on a custom graphic repository 212 that is an application or a web-server. These elements are then input to a graphics rendering engine 213, residing on an operator station. This engine downloads and presents the control animation graphics 210 to the end-users. This engine can fit into both the thick-client or thin-client paradigms. The graphics thus rendered communicate with a control engine 211, which is a virtual machine that collects inputs from devices such as sensors, transducers or intelligent electronic devices. This engine also performs some computation, based on pre-defined control algorithms downloaded by the end-user and outputs the computed control variables to the devices. The control engine 211 also provides an interface for remotely reading, modifying and configuring the control variables. Control engines 211 can be proprietary or comply with standards such as IEC-61131. The control engine 211 further communicates with a control object extractor 205, which retrieves information about control variables in use by the control engine 211 and creates corresponding control objects 204, which represent control variables or a collection of control variables, managed by an industrial controller, in a variety of formats including XML, Oracle DB elements etc. These control objects 204 are then input to a control objects aggregator 203, which collects control objects 204 from one or more control object extractors 205, aggregates the collected control objects 204 and formats the aggregation. The output of this process is one or more aggregated control objects 202, which are fed back to the control object 204 to graphics associator.

Fig. 3 shows a controller-centric architecture wherein the controller is required to implement a majority of the functionality. This enables the controller to act as a self- contained object of deployment with maximum functionality. This architecture is useful when the controller is resource intensive and has the requisite processing power to execute all the requisite functions. This paradigm delineates the method of building graphics to contain three distinct, functional entities including the thin-client based graphics builder 301, the thin-client based operator station 302 and the controller 303. The communication between the thin-client based operator station 302 and the controller 303, the thin-client based graphics builder 301 and the controller 303, and further, the graphics elements repository 309 and the thin-client based graphics builder 301, are now enabled via technologies such as XML RPC, SOAP, HTTP, AJAX, JNLP etc.

The thin-client based graphics builder 301 is comprised of the graphics builder 305 and the control objects to graphics associator 307. Graphic elements 304, animation graphics 306 and control animation graphics 308 are the data elements that are used or produced in this new abstraction to enable a controller-centric architecture. The thin-client based operator station 302 now houses the graphics-rendering engine 316 alone. The elements of the controller 303 include the control engine 314, the control object extractor 312, the control objects aggregator 313 and the graphics elements repository 309. The controller 303 may optionally include a custom graphics repository 315 that could alternatively reside outside the controller. The data that is produced and consumed in the controller includes the control objects 311 and the aggregated control objects 310. Further, the graphics elements repository 309 is exposed to the thin-client based graphics builder 301 by such technologies as XML RPC, SOAP, HTTP₅ AJAX, JNLP etc. providing a communication-protocol independent architecture. By means of this delineation, the present invention proposes a framework that does not place restrictions on where the processes within industrial control have to be carried out. This enables de-centralized and distributed computing.

Fig. 4 proposes an alternative architecture that is thin-client centric. The primary difference between this architecture and the controller-centric architecture is that the control objects aggregator 409 is moved into the thin-client based graphics builder 401, consequently producing the aggregated control objects 408 within, the graphics builder 405 as well. This ameliorates the requirement of the controller 403 having resource- intensive substrates to process the aggregation of control objects.

Claims

1. A system for enabling a thin-client based graphics building tool for industrial controllers, which control one or more field devices communicating via several standard field bus protocols (such as PROHBUS, HART etc.) said controllers and devices in the system interacting with several other logical and functional entities including operator work stations, web-servers and data-repositories, communicating over several networks via protocols such as HTTP and TCP/IP comprising: a. Means for creating representations for control parameters, which are obtained from field devices, indicating the present state of the processes; b. Means for building graphical interfaces, including animation, used to control industrial processes using one or more graphical elements; and c. Means to render the graphical interfaces, wherein the graphical interfaces are finally presented to the end-user.

2. A system of claim 1 wherein the industrial controllers are resource-constrained.

3. A system of claim 1 wherein the means for creating representations for control parameters, which are obtained from field devices, include: a. A control engine, which is a virtual machine that collects inputs from devices such as sensors, transducers or intelligent electronic devices, processes some logic associated with those devices and outputs appropriate resutls; and b. A control object extractor, which retrieves information about control variables in use by the control engine and creates corresponding control objects, which represent control variables or a collection of control variables, managed by an industrial controller.

4. A system of claim 2 wherein the control engine is compliant with both proprietary and industrial standards such as EEC-61131.

5. A system of claim 2 wherein the control variables can measure both discrete and analog values.

6. A system of claim 2 wherein the control objects can be represented in a variety of formats including XML and Oracle DB elements.

7. A system of claim 1 wherein the means for building graphical interfaces, including animation, used to control industrial processes using one or more graphical elements include: a. A Graphics Builder, which is used to build relevant graphics, including animation graphics, which refer to an assembly of graphic elements with animation and state transition properties; and b. A Control object to graphics associator, which includes: i. Means to allow the user to map the animation and state transition properties in animation graphics with elements of aggregated control objects wherein aggregated control objects refer to a representation of a group of industrial controllers that act in unison to realize an industrial control process with an industrial plant; ii. Means to produce, as a result of the association in .i., control animation graphics, which are data structures that are a union of animation graphics and control objects or aggregated control objects, such that a relationship between the graphic elements and the control objects or aggregated control objects, exist; and iii. Means to store the control animation graphics on a custom graphic repository;

8. A system of claim 6 wherein the graphic elements can be represented in variety of formats such as SVG, Macromedia FLASH, XAML and GDI.

9. A system of claim 6 wherein the aggregated control objects are a special class of control objects, which can be stored in proprietary or standardized formats such as

XML and Oracle DB elements

10. A system of claim 6 wherein the custom graphic repository an application or a web-server;

11. A system of claim 6 wherein the custom graphic repository is distinct from the means to create representations;

12. A system of claim 2 and 6 wherein the means for creating representations and the means for building graphical interfaces, include: a. A control objects aggregator, which collects control objects from one or more control object extractors, aggregates the collected control objects and formats the aggregation, whose output is one or more aggregated control objects, which are fed back to the control object to graphics associator.

13. A system of claim 1 wherein the means for rendering the graphical interfaces, wherein the graphical interfaces are finally presented to the end-user include: a. A Graphics Rendering Engine, which displays the graphical interfaces to the end-user residing on an operator workstation;

14. A system of claim 12 wherein the operator workstation can be both a thick-client or a thin-client based architecture.

15. A system of claim 1 wherein distributed security logic located on the controller and thin client, guarantees authorized access to the components within the system.