Patent Publication Number: US-8116888-B2

Title: Parameter setting system and method for programmable logic controller

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates to programmable logic controller (PLC) and, particularly, to a parameter setting system and method for PLC. 
     2. Description of Related Art 
     With development of automation, PLCs are used widely. At present, when an operator of a PLC needs to change a parameter of the PLC, such as input parameter (I), output parameter (O), command parameter (C), state parameter (S), auxiliary parameter (A), and register parameter (R), she must change scale value of the parameter. However, the operator of the PLC needs to use programs to make corresponding changes to the scale value of the parameter. This process is operationally complex and inconvenient. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of an embodiment of a parameter setting system for programmable logic controller (PLC). 
         FIG. 2  is a flowchart of an embodiment of a parameter setting method for programmable logic controller (PLC). 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an exemplary embodiment of a parameter setting system for programmable logic controller (PLC) includes a document module  10 , a main program module  20 , a parameter storage module  30 , an interface display module  40 , and a display interface  50 . 
     The document module  10  is configured to store application documents and an extensible markup language (XML) document of the PLC. The XML document includes names and scale values of parameters I, O, C, S, A, and R. For example, scale value of the parameter C is 0-512, (as shown in table 1 below). The scale value of each of parameters in the XML document is used in succeeding process of PLC. The main program module  20  is configured to read the XML document from the document module  10  and store the name and scale value of each of the parameters of the XML document in the parameter storage module  30 , and output a control signal to the interface display module  40 . The interface display module  40  receives the control signal from the main program module  20  and reads the names and scale values of the parameters I, O, C, S, A, and R stored in the parameter storage module  30 , and displays the names and scale values of the parameters via the display interface  50 . A operator of a PLC selects a parameter name on the display interface  50  and sets the value of the parameter according to scale value corresponding to the parameter name. 
     
       
         
           
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
             
            
               
                   
                 IOCSA name 
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                   
                 IB 
                 IK 
                 OB 
                 OK 
                 C 
                 S 
                 AB 
                 AM 
                 AG 
               
               
                   
               
               
                 IOCSA 
                 384 
                 128 
                 384 
                 128 
                 512 
                 512 
                 1024 
                 512 
                 512 
               
               
                 scale 
               
               
                 value 
               
               
                   
               
            
           
           
               
               
            
               
                   
                 R name 
               
            
           
           
               
               
               
               
               
               
               
            
               
                   
                   
                 R 
                 Ra 
                 Rb 
                 Rc 
                 Rd 
               
               
                   
                   
               
               
                   
                 R scale value 
                 256 
                 256 
                 1024 
                 2048 
                 6656 
               
               
                   
                   
               
            
           
         
       
     
     Before using, the operator of the PLC creates an XML document, which includes the names and scale values of the parameters I, O, C, S, A, and R. The XML document is placed in the document module  10  of PLC, and in a same path as application documents of PLC. When initializing PLC, the main program module  20  reads the XML document from the document module  10  and stores the names and scale values of the parameters I, O, C, S, A, and R of the XML document, and outputs a control signal to the interface display module  40 . The interface display module  40  reads the names and scale values of the parameters I, O, C, S, A, and R stored in the parameter storage module  30 , and displays the names and scale values of the parameters via the display interface  50 . The operator of the PLC selects a parameter name on the display interface  50 , and sets a value of the parameter according to the scale value of the selected parameter. The value of the selected parameter will be used in succeeding process for the PLC after the value of the selected parameter is set. If value of the parameter needed by the operator is beyond scale value of the parameter on the display interface  50 , the scale value can be changed on the display interface  50  by changing the scale value of the parameter in the XML document, so that the operator can select the needed value. 
     For example, if the maximum scale value of parameter C is 512, then the value of parameter C can be selected from 0-512 on the display interface  50 . Namely, the parameter name of the parameter C is selected on the display interface  50 , the value from 0 to 512 can be used by PLC. If the value of the parameter C is 600, which is greater than the maximum scale value 512, the scale value of parameter C in XML document must be changed in order to make the value of the parameter C valid. For example, the maximum scale value of the parameter C is changed to 1024, and then the value 600 and other values from 0 to 1024 of the parameter C can be used by PLC. 
     Referring to  FIG. 2 , an exemplary embodiment of a parameter setting method for a PLC includes the following steps. 
     Step S 1 : determining whether an XML document exits in the document module  10  of PLC using the main program module  20 . 
     Step S 2 : if the XML document does not exist, the main program module  20  reads inherent names and scale values of the parameters I, O, C, S, A, and R of PLC, and applies the parameters to succeeding process for PLC. 
     Step S 3 : If the XML document exists, the main program module  20  determines whether presetting names and scale values of the parameters exist in the XML document; if not, then go back to step S 2 . 
     Step S 4 : if yes, the main program module  20  reads the names and scale values of the parameters from the XML document and storing them in the parameter storage module  30 , and outputting a control signal to the interface display module  40 . 
     Step S 5 : the interface display module  40  receives the control signal from the main program module  20  and controls the display interface  50  to display the names and scale values according to the control signal, and determines whether a value needed to be set in a selected parameter is within the scale value of the selected parameter. 
     Step S 6 : if yes, selecting the parameter name and setting the needed value of the parameter on the display interface  50 , and applying the setting value to succeeding process for the PLC. 
     Step S 7 : if no, revising the scale value of the parameter in the XML document, and then go back to step S 4 . 
     The parameter setting system and method for a PLC uses an XML document which includes names and scale values of the parameters I, O, C, S, A, and R in document module  10  of the PLC. The main program module  20  reads the XML document and stores the names and scale values of the parameters I, O, C, S, A, and R from the XML document in the parameters storage module  30 , and outputs a control signal to the interface display module  40 . The interface display module  40  reads names and scale values of the parameters from the parameter storage module  30  and controls the display interface  50  to display the names and scale values. Operations of PLC set value of each of the parameters on the display interface  50 , and revising names and scale values of the parameters I, O, C, S, A, and R in the XML document in order to change the maximum scale value of the parameters on the display interface  50 . The parameter setting system and method for PLC is operationally simple and convenient. 
     The foregoing description of the exemplary embodiments of the disclosure has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to explain the principles of the disclosure and their practical application so as to enable others skilled in the art to utilize the disclosure and various embodiments and with various modifications as are suited to the particular use contemplated. Alternately embodiments will become apparent to those skilled in the art to which the present disclosure pertains without departing from its spirit and scope. Accordingly, the scope of the present disclosure is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.