Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
  • G06F16/90—Details of database functions independent of the retrieved data types
  • G06F16/95—Retrieval from the web
  • G06F16/957—Browsing optimisation, e.g. caching or content distillation

Definitions

• the invention relates to an automation system and a method for visualizing a system.
• the web page is constantly updated on the server side in order to enable cyclical page updates.
• the disadvantage here is that the entire web page - including all graphics and the like - must be transferred for each update, even if only one or a few parameters change. A large amount of unnecessary data is therefore transmitted over the Internet, which is limited in its bandwidth anyway.
• the invention is based on the object of creating an improved automation system and an improved method for visualizing a system.
• the invention allows the system controlled by an automation system and / or sub-systems of such a system to be visualized on a client, for example an operating console, by means of a so-called web browser.
• Documents in a markup language e.g. Hypertext Mark up Language (html), or Extended Mark up Language (XML) can be used.
• the invention allows the constant updating of parameter values of the visualized sub-system of the system displayed in the document on the browser. This can be done efficiently and with only a small required channel capacity by using so-called script technology.
• so-called polling can take place on the client side at specific predetermined time intervals, for example, of one second or one minute. This then leads to the query of only the changed parameter values from a processing unit. Only the changed parameter values are then transferred to the client with a corresponding script, so that the corresponding parameter values are updated in the document displayed by the browser. The assignment of the changed parameter values to display fields in the document takes place on the basis of the scripts transferred with the changed parameter values.
• This script is generated on the server side for each change in value, ie a value- and page-specific script is generated for each change in value.
• Script languages are e.g. Javascript, Visual Basic, SVG, vrml, html, dht l and XML in question.
• the processing unit can be a so-called programmable logic controller (PLC), which stores the current parameter values with a time stamp.
• PLC programmable logic controller
• the invention permits good scalability of the automation system.
• the invention allows a so-called timeout to be determined efficiently. If the cyclic polling of the client is omitted, it can be concluded that the client process, ie the visualization of the relevant plant subsystem, has been canceled by the client user. Complex time-outs of, for example, twenty minutes - as is customary in the prior art - can therefore be dispensed with.
• Another advantage of the automation system according to the invention is that it can be firewall-compatible, in particular when using the so-called TCP / IP protocol, which is also used on the Internet.
• Another advantage of the invention is that commercially available browser programs on the client side can be used to display the documents in a markup language, e.g. Netscape Navigator or Microsoft Internet Explorer. It is also advantageous to use markup languages to visualize client-independent data in various types of display.
• a markup language e.g. Netscape Navigator or Microsoft Internet Explorer. It is also advantageous to use markup languages to visualize client-independent data in various types of display.
• the invention also allows redundancy to be implemented in an automation system in an efficient manner.
• FIG. 1 is a block diagram of an embodiment of an automation system according to the invention
• Fig. 2 is a flow chart for visualizing a plant sub-system.
• the automation system of FIG. 1 has a client 1 with a browser 3.
• the browser 3 can be a conventional Internet browser, for example Netscape Navigator or Microsoft Internet Explorer.
• URL Uniform Resource Locator
• Web page 8 can serve to visualize a specific subsystem of the system controlled by the automation system.
• the web page 8 typically contains one or more display fields for displaying current parameter values such as of pressures, temperatures, levels and other sensor measurements or machine parameters.
• the client 1 is connected to a server 4.
• the TCP / IP protocol can serve as the protocol for the connection between client 1 and server 4. In this case, it is possible to arrange an Internet-like computer network between the client 1 and the server 4.
• the server 4 is connected to a memory 7, which contains the URL of the web page 8 currently displayed on the client 1.
• the server 4 therefore knows from each connected client which website is currently being visualized.
• the memory 7 also contains a table which contains the parameter names of the respective system subsystem belonging to each web page. By accessing the memory 7, the server 4 can thus determine the parameter names displayed in the current web page of the client 1.
• the server 4 is also connected to a processing unit 2.
• the processing unit 2 can be a so-called programmable logic controller (PLC) to which one or more field devices 6 are connected.
• PLC programmable logic controller
• the processing unit 2 has a memory 5 for storing the current parameter values with a corresponding time stamp. As a result, the time course of the parameter values can be called up from the memory 5 by the processing unit 2. If there is not enough space on processing unit 2, you can also change the parameter values with
• Time stamps are temporarily stored in server 4.
• the server 4 and the processing unit 2 can also be used together in be implemented in a device, ie a PLC delivers websites with their values directly.
• the user of the client 1 first enters the URL of the desired web page 8 in the browser 3.
• the URL can be entered by selecting a so-called hyperlink, for example by clicking with a mouse.
• the web for visualizing the system is preferably structured hierarchically, so that the user can select subsystems of the system on a start page by selecting appropriate hyperlinks.
• the URL of the desired web page 8 is stored in the hyperlinks.
• the web page 8 is transmitted from the server 4 to the client 1 and visualized by the browser 3.
• the URL of the web page 8 is stored by the server 4 in the memory 7.
• the server determines the parameters belonging to the web page 8 from the table stored in the memory 7 and queries the current parameter values from the processing unit 2. This transmits the current parameter values to the server 4, which transmits them to the client 1 as part of the web page 8.
• the client 1 queries the server 4 for updates of the parameter values by means of cyclical polling.
• a time stamp of the last update of the parameter values is also transmitted.
• the server 4 again determines the parameters of the web page 8 from the memory 7 and queries the processing unit 2 for those parameter values that have changed since the last update, that is to say those parameter values that have a larger time stamp than that of the client 1 have time stamp transmitted to server 4.
• These updated parameter values are then transmitted from the processing unit 2 to the server 4.
• the server 4 generates a script which can enter all changed parameter values in a data field of the web page 8 assigned to the corresponding parameter or can visualize the parameter graphically or textually.
• the assignment of the parameter names to the data fields or other graphic or textual representations on the web page 8 is carried out according to the table in the memory 7.
• a bar for a fill level is displayed on the website, e.g. not the fill level is transferred in meters, but a script is transferred that contains a rectangle with e.g. 1 cm wide and 10 cm high (according to the fill level).
• the script with the changes in the representation is then transmitted to the client 1 and interpreted by the browser 3, so that the corresponding display elements of the web page 8 can be updated with the changed parameter values.
• This process can be repeated cyclically at fixed time intervals, the cycle time can be selected depending on the temporal dynamics of the system process to be visualized.
• step 20 the web page of the desired plant sub-system is first loaded with the current parameter values.
• the URL of the relevant web page is saved on the server side.
• step 21 the update of the parameter values of the web page is requested by the client at a later point in time.
• the server determines in step 22 the parameters belonging to the web page.
• the server receives the parameter values that have changed since the last update from the memory of the processing unit.
• step 23 the server then generates a script which can generate the changes in the display in the client for the changed parameter values.
• step 24 this data is then interpreted by the client's browser and the web page is updated accordingly.

Landscapes

• Engineering & Computer Science (AREA)
• Databases & Information Systems (AREA)
• Theoretical Computer Science (AREA)
• Data Mining & Analysis (AREA)
• Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• Information Transfer Between Computers (AREA)
• Information Retrieval, Db Structures And Fs Structures Therefor (AREA)
• Computer And Data Communications (AREA)
• Digital Computer Display Output (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2001
  • 2001-07-03 DE DE10132038A patent/DE10132038A1/de not_active Ceased
• 2002
  • 2002-06-20 EP EP02754245A patent/EP1402422A2/de not_active Withdrawn
  • 2002-06-20 CN CNB028136055A patent/CN1279476C/zh not_active Expired - Fee Related
  • 2002-06-20 WO PCT/DE2002/002275 patent/WO2003005234A2/de not_active Application Discontinuation
• 2003
  • 2003-12-17 US US10/738,538 patent/US20040205197A1/en not_active Abandoned

Non-Patent Citations (1)

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