Abstract:
Systems and methods for object linking and embedding for process control networks are disclosed. The exemplary system may include one or more field devices. The system may also include a process control server for monitoring the field devices, storing field information and one or more parameters for each of the field devices, and associating each of the field devices input/output data with a text-based tag. The system may also include a client computer capable of accessing the one or more parameters of each field device by identifying the field information containing the desired text-based tags. The data may be displayed in real time.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Patent Application No. 60/811,554 filed Jun. 7, 2006 entitled “OPC TAG EDITOR”, which is incorporated fully herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates generally to a tag editor system, and more particularly to a tag editor system for object linking and embedding for process control networks. 
     BACKGROUND OF THE INVENTION 
     In the process automation industry, object linking and embedding for process control (OPC) provides a standard for communicating with field devices. This standard allows for accessing process data, alarms, events, and historical process data. In a typical monitoring and control network, one or more servers are equipped with the OPC Server application which receives field device data and stores the data in volatile memory. This data is constantly being updated through polling functions initiated by the process control server or by a predetermined reporting cycle that the field devices follow to report the status of the I/Os (Inputs/Outputs) and field devices. The addressing information needed to access the field devices is stored in the process control server&#39;s tag database. The server tag database encapsulates the physical field device addressing into a simple text-based tag that is accessible by any clients with access to the network. The server tag database is specific to the types of field devices used in an application. This database requires considerable configuration efforts. 
     A client computer  108  is typically equipped with a Human Machine Interface (HMI) application that is used to visualize and interact with the field devices using symbolic images and standard windows widgets (e.g. listbox, textbox, radio button, checkbox). The HMI contains programs/drivers capable of communicating with any process control server accessible locally on the same computer or from the network. The HMI application&#39;s tag database is configured with the process control server tags that are referenced on the graphic pages. The process control server reports changes in the tag values to the HMI application, which then updates the appropriate graphical element. The HMI tag database is specific to the HMI and its graphics. This database also requires considerable configuration efforts. 
     One common method of displaying real-time server tag information on an HMI graphic consists of first adding a tag to the HMI tag database that references the process control server tag. Then a display element is added to the graphic (e.g. Textbox). Finally, the real-time display of that element is associated with the appropriate HMI tag database tag. The effort required to configure an HMI display and edit a large server tag database is considerable and error prone. Accordingly, an efficient device and method are needed for displaying and editing real-time server tag data without requiring the explicit configuration of the HMI tag database. 
     SUMMARY OF THE INVENTION 
     It is, therefore, an object of the present invention to provide systems and methods for accessing object linking and embedding for process control data. It is another object of the present invention to provide real-time access to the data and to achieve this without requiring the explicit configuration of the Human Machine Interface (HMI) tag database. 
     In an exemplary embodiment, a tag editor may operate on a client computer with a process control server monitoring the field devices, storing physical addressing information and/or one or more parameters for each of the field devices, and associating each of the field devices with a text based tag. The client computer may access the one or more parameters of each field device by identifying the text based tag. In an exemplary embodiment, the tag editor may provide access to the text-based tags in a system after configuration of a name of the process control server and a name of at least one PID (Proportional, Integral, Derivative) loop, analog inputs, discrete inputs, analog outputs, discrete outputs, counters, or other parameters of the field device containing the tags. In a preferred embodiment, the tag editor displays the real-time data in a user-friendly, readable format. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objectives and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference numbers refer to like parts throughout, and in which: 
         FIG. 1  is a generalized schematic of a first exemplary embodiment of the present invention. 
         FIG. 2  is a flow chart illustrating an exemplary embodiment of the present invention. 
         FIG. 3  is a generalized schematic of a second exemplary embodiment of the present invention. 
         FIG. 4  is an exemplary display containing text-based tags and the corresponding parameters. 
     
    
    
     Shown in  FIG. 1  is an example of a monitoring and control network. A Server PC is equipped with the OPC server application which takes field device data and stores the data in volatile memory. This data is constantly being updated through polling functions initiated by the OPC server or by a predetermined reporting cycle which the filed devices follow to report the status of the I/O and field devices. The addressing information needed to access the field devices is stored in the OPC Server&#39;s tag database. The OPC Server tag database encapsulates the physical field device addressing into a simple text-based tag which is accessible by OPC clients. For example, the OPC server&#39;s tag database may define the text-based tag LOOP 1.PV to represent the value of the field device&#39;s I/O value addresssable as buffer page 0x54, memory offset 0x1098. Clients of the OPC Server do not have to be concerned with the physical addressing of the field devices. The OPC Server tag database is specific to the types of field devices and requires considerable configuration efforts. 
     A client PC is equipped with a HMI (Human Machine Interface) application which is used to visualize and interact with the field devices using symbolic images and standard windows widgets (e.g. listbox, textbox, radio button, checkbox). The HMI contains programs/drivers capable of communicating with any OPC server accessible locally on the same computer or from the network. The HMI application&#39;s tag database is configured with the OPC Server tags that are referenced on the graphic pages, The OPC Server reports changes in the tag values to the HMI application, which then updates the appropriate graphical element. The HMI tag database is specific to the HMI and its graphics and requires considerable configuration efforts. 
     As done by common practice, real-time OPC Server tag information is displayed on a HMI graphic by: first adding a tag to the HMI tag database that references the OPC Server tag; and second adding a display element to a graphic (e.g. Textbox) and associating the real-time display of that element to the appropriate HIMI tag database tag. Other graphic widgets are added to provide convenient user input interfaces such as limited checked input boxes, sliders, etc. The effort required to configure a HMI to display and edit a large OPC Server tag database is considerable and error prone. 
     HMI applications commonly allow for some graphical “plug-in” capability using any standard or proprietary technology (e.g. ActiveX, Java Bean). These “plug-in” features allow for the execution and interaction with third-party binary extensions to the graphics display. 
     This invention proposes the introduction of a graphics binary extension to the display and edit real-time OPC tag data without requiring the explicit configuration of the HMI tag database. Given only the name of the OPC Server and some wildcard set of tag names, the OPC tag editor can properly display and allow edits to any OPC Server data, The OPC tag editor has built-in communication capabilities to communicate directly with any OPC Server. The OPC tag editor can display the real-time data in various formats including but not limited to a textbox, grid/table, graphical chart, or free-form HTML which may include any “HTML plug-in” such as flash, SVG and VML. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , an exemplary tag editor system  100  is shown. This type of design is frequently used in the process automation industry. One or more input/output (I/O) devices and/or field devices  102  may be used to measure or calculate various parameters related to a process. The I/Os and field devices  102  may be connected to a process control server  104 . The process control server  104  may be equipped with the object linking and embedding for process control (OPC) server application which collects field device data and stores the data in volatile memory. This data is continuously being updated through polling functions initiated by the process control server  104  or by a predetermined reporting cycle that the I/Os and field devices  102  follow to report the status of the I/Os and field devices  102 . The addressing information needed to access the I/Os and field devices  102  is stored in a server&#39;s tag database  106 . 
     The server&#39;s tag database  106  encapsulates the physical field device addressing into a text-based tag that is accessible by any client computers  108  with access through a network  110  connected to the process control server  104 . The network  110  may connect to one process control server  104  (as shown in  FIG. 1 ) or it may connect to multiple servers. Multiple servers may be used to control separate processes either at the same location or at various separate locations. The network  110  may allow access to any of its connected servers. There may also be more than one client computer  108  connected to the network  110 . An exemplary process control server  104  may associate each field device&#39;s input/output data with a text-based tag. For example, the server tag database  106  may have the text-based tag “LOOP1.PV” associated with the value of the field device&#39;s I/O value addressable as buffer page 0x54, memory offset 0x1098. An exemplary embodiment of the tag editor system may allow this text-based tag and its value to be accessed from the client computer  108  with minimal configuration efforts. 
     According to an exemplary embodiment of a tag editor system, a client computer  108  may contain a tag editor extension. The tag editor may have built-in communication capabilities to communicate directly with any process control server  104  in the network. The tag editor may allow a client computer  108  to access the server&#39;s tag database  106  after configuring the name of the process control server  104  (to identify the desired server if multiple servers are in use) and field information, for example, the PID (Proportional, Integral, Derivative) loops, analog inputs, discrete inputs, analog outputs, discrete outputs, counters, or other parameters of the field device containing the desired tags. The use of PID loops is common in process control. It is a continuous feedback loop used to monitor the value of a process variable (e.g. voltage, temperature, rate of flow). If the value of the process variable deviates from the “setpoint”, then corrective action is computed by a PID controller from a computation based on the error (proportional), the sum of all previous errors (integral), and the rate of change of the error (derivative). So, in an exemplary embodiment, once the process control server  104  receives the PID loop name(s), the field device I/O data is returned to the client computer  108 . The data may then be displayed through a client application  112  on a client computer  108 . An exemplary embodiment of the tag editor system may allow for real-time field device I/O data to be displayed on the client computer  108 . An exemplary embodiment of the tag editor system may also allow edits to any tag data stored in the server&#39;s tag database  106 . 
     In an exemplary embodiment of the tag editor system, the client computer  108  may be equipped with a Human Machine Interface (HMI) application  112 . The HMI application may be used to visualize and interact with the field devices  102  using symbolic images and standard windows widgets (e.g. listbox, textbox, radio button, checkbox). The HMI application  112  may contain program/drivers capable of communicating with any process control server  104  accessible locally on the same computer or from the network  110 . An exemplary embodiment of the tag editor system may allow for the HMI tag database  114  to be eliminated from the system entirely. 
     Referring to  FIG. 2 , a flowchart illustrates an exemplary method for displaying and editing tag data for object linking and embedding for process control. The control process is initiated (block  202 ). The process control server  104  monitors the inputs/outputs and field devices  102  as the process continues (block  204 ). The data from the field devices is stored in the process control server&#39;s volatile memory. This data is continuously updated through polling functions initiated by the process control server  104  or by a predetermined reporting cycle that the field devices follow to report the status of the inputs/outputs and field devices  102 . The process control server  104  stores the physical addressing information and field device parameters in the server&#39;s tag database  106  (block  206 ). The server&#39;s tag database  106  encapsulates the physical field device addressing into a simple text-based tag that may be accessed by any client computer  108  with the tag editor system. The process control server  104  also associates each field device input/output data with a text-based tag (block  208 ). 
     An exemplary embodiment of the tag editor system allows a client computer  108  to access any field device parameters involved in the process (block  210 ). The client computer  108  identifies the process control server (if more than one is in the network) and the name of the PID loop containing the desired text-based tag(s). An exemplary embodiment of the tag editor system enables the client computer  108  to allow editing and displaying of any desired field device data involved with the process (block  212 ). Real-time data may be displayed on the client computer  108  without explicitly configuring the HMI tag database  114 . 
     Referring to  FIG. 3 , a second exemplary tag editor system  300  is shown. This system is similar to the system shown in  FIG. 1 , however there are multiple process control servers  304  (similar to previously mentioned  102 ) connected to the network  310  (similar to previously mentioned  110 ), and there are multiple client computers  308  (similar to previously mentioned  108 ) with access to the network  310  (similar to previously mentioned  110 ). Multiple processes are being monitored and controlled, and multiple users have access to each of these processes. In this exemplary embodiment, a client computer  308  may be required to identify a specific process control server  304  by name when accessing tag data. Each client computer may be equipped with a tag editor that has built-in communication capabilities to communicate directly with any of the process control servers  304  in the network. An exemplary embodiment of the tag editor system may allow for an HMI tag database  314  (similar to previously mentioned  114 ) to be eliminated from the system entirely or minimize updating or use of the HMI tag database  314 . 
     Referring to  FIG. 4 , an exemplary display containing text-based tags and data from a sample PID loop is shown. A PID loop object in a distributed control system (DCS) may contain 30 or more “tags”. A table, such as the one in  FIG. 4 , may be a desirable method of displaying all of the text-based tags along with the current parameter values updating in real time. Alternately, spreadsheets may be used along with graphic and text editors to create a graphic display of any input/output or field device parameter being monitored. All of the PID loop tags may be accessible through the tag editor by having the client computer configure the name of the process control server and the name of the PID loop. 
     It will be understood that the foregoing is only illustrative of the principles of the invention and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. Accordingly, such embodiments will be recognized as within the scope of the present invention. 
     Persons skilled in the art will also appreciate that the present invention can be practiced by other than the described embodiments, which are presented for purposes of illustration rather than of limitation and that the present invention is limited only by the claims that follow.