Symbol Configuration Editor

Overview

The symbol configuration functionality allows you to configure external access to variables. The symbols and the variables can then be monitored in the Web server and be accessed by external applications, such as Vijeo-Designer or OPC server.

To configure symbols for an application, double-click the Symbol Configuration node in the Tools tree. The Symbol configuration editor view opens.

The editor contains a table. Depending on the set filter, it shows the available variables, or just those already selected for the symbol configuration. For this purpose, the concerned info pop-ups with POUs definition or libraries are listed in the Symbols column. You can expand them in order to show the corresponding variables.

NOTE: The number of variables you can configure is not limited.

The restrictions depend on the different monitor platforms:

Platform	Maximum Limit
Web server	16 000 bytes
OPC UA	10 000 variables
HMI	Depends on RAM of each model

Elements of the Toolbar

Element	Description
View button	The View button allows you to set the following filters to reduce the number of displayed variables:
	Unconfigured from Project	Even variables not yet added to the symbol configuration, but available for this purpose in the project, are displayed.
	Unconfigured from Libraries	Also variables from libraries, not yet added to the symbol configuration, but available for this purpose in the project, are displayed.
	Symbols exported via attribute	This setting is effective only when the unconfigured variables are displayed (see the two filters described above). It has the effect that also those variables are listed, which are already selected for getting symbols by {`attribute 'symbol' := 'read'`} within their declaration. Such symbols are displayed grayed. The Attribute column shows which access right is set for the variable by the pragma. Refer to the following description of the Access Rights column.
Build button	The Build button allows you to build the project. The build run refreshes the variables view in the Symbol Configuration editor.
Settings button	The Settings button allows you to activate the following options:
	Support OPC UA features	This function is not supported.
	Include comments in XML	This has the effect that comments assigned to variables are also exported to the symbol file.
	Include node flags in XML	This has the effect that the flags that contain the namespace are also exported to the symbol file. They provide additional information on the origin of the node in the namespace when OPC UA is active.
	Configure comments and attributes...	Opens the Comments and Attributes dialog box that allows you to configure the contents of the symbol configuration and the XML file.
	Configure synchronisation with IEC tasks...	Opens the Options tab of the Properties dialog box of the selected controller. Refer to the description of the Access variables in sync with IEC tasks option in the EcoStruxure Machine Expert Menu Commands Online Help. NOTE: Do not activate the option Configure synchronisation with IEC tasks... for motion and real time-critical application because the delayed start of IEC tasks leads to a higher jitter. For further information, refer to the paragraph Additional Information on the Option Configure synchronisation with IEC tasks....
	Compatibility Layout	Select this option to calculate the data output in the same way as in SoMachine / SoMachine Motion versions prior to V4.3. Do not use this layout together with exported `STRUCT`s that use the attributes pack_mode or relative_offset. The data layout created for the client is adapted as far as possible to the layout created by the compiler.
	Optimized Layout	Select this option to calculate the data output in an optimized form, independent of the internal compiler layout. The optimization impacts only variables of a structured type and function blocks. No gaps with padding bytes are generated for members that are not published, for example, because they are deactivated in the Symbol Configuration. For internal members, for example, function blocks implementing interfaces, no gaps are created either. This option is by default selected for projects with EcoStruxure Machine Expert. The setting is preserved after a Project update.
Tools button	Save XML Scheme File...	Opens the dialog box for saving a file in the file system. Allows you to create an XSD (XML Schema Definition) format of the symbol file, for use in external programs.

Description of the Table

Columns of the Symbol configuration table:

Column	Description
Symbols	The column shows a list of POUs. You can select variables to be exported. If you select variables of a structured data type, all members of the structure will be exported. You may also select only particular member variables in the dialog box Symbol Configuration for Data Type. Click the browse ... button in the Members column to open this dialog box. For further information, refer to the description of the Members column.
Access Rights	To modify the access rights for a selected item, click the Access Rights column. Each mouse-click switches the symbol within the following definitions: : read and write : write-only : read-only none
Maximal	Shows the maximum access rights.
Type	Shows the data type of the variable. Variables of an alias data type are displayed as shown in the following example of a variable: `myVar : MY_INT,`, where `MY_INT` is an alias declared as: `TYPE MY_INT : INT; END_TYPE`. In this case, the Type column shows `MY_INT : INT`.
Members	Click the ... button in the Members column to open the Symbol Configuration for Data Type dialog box. It allows you to select only particular member variables. In case of nested types, this dialog box again provides a button to open another Symbol Configuration for Data Type dialog box. This selection applies to all instances of this data type for which symbols are exported. If not all members of a structured type are exported, then an asterisk (*) is displayed in the check boxes of the members to indicate that all exportable members of that type are exported.
Comment	Shows any comments which have been added in the declaration of the variable.

NOTE: With the POU property Link Always, an uncompiled POU can be forced to be downloaded to the controller. If this property is set in the Build tab of the Properties dialog box of the selected POU, then all variables declared in this POU are available, even if those variables are not referenced by other code. Alternatively, you can use the pragma {attribute linkalways} to make not compiled variables available in the symbol configuration.

Variables which are configured to be exported but which are not valid in the application, for example because their declaration has been removed, are shown in red. This also applies to the concerned POU or library name.

By default, a symbol file is created with a code generation run. This file is transferred to the device with the next download. If you want to create the file without performing a download, use the command Generate code, by default available in the Build menu.

NOTE: Variables of a global variable list (GVL) will only be available in the symbol configuration if at least one of them is used in the programming code.

Comments and attributes Dialog Box

The Comments and attributes dialog box opens upon clicking Settings > Configure comments and attributes. It contains the following elements:

Element	Description
Symbol table contents
Enable extended OPC UA information	This function is not supported.
Include comments
Include attributes
Also include comments and attributes for type nodes
XML symbol file contents
Include namespace node flags	Namespace node flags provide additional information about the origin of a node in the namespace. Node flags are available in the symbol table when OPC UA is activated. Deselect this option to prevent namespace node flags from being inserted in the XML file if your parser cannot process them.
Include comments	Select this option to save comments in the XML file. In SoMachine / SoMachine Motion versions prior to V4.4, this includes the setting Prefer docu comments.
Include attributes	Select this option to save attributes in the XML file.
Also include comments and attributes for type nodes	This option is only available if the option Include comments or the option Include attributes is activated. If this option is selected, the information for type nodes is also included (user-defined types, such as STRUCT and ENUM elements). If this option is not selected, comments and attributes are only available for directly exported variables.
Select comments These parameters are only available if one of the Include comments options is activated.
Include docu comments: ///They start with triple slash and are usually /// formatted in ReST (library documentation)	Select the options to determine the kind of comments that are saved in the symbol configuration.
Include normal comments: (IEC/ Pascal style comments ) // C++-Style comments with double-slash
Always include both types of comments
Prefer docu comments, fallback to normal ones
Prefer normal comments, fallback to docu comments
Filter Attributes (case insensitive) These parameters are only available if one of the Include attributes options is activated.
Include all attributes (“foo”, “bar”, “foo.bar”)	Select the options to determine the attributes that are saved in the symbol configuration.
Match simple identifiers (“foo”, “bar”)
Include attributes starting with:
Filter Attributes with regular expression

Additional Information on Configure synchronisation with IEC tasks...

To achieve synchronous, consistent access, the runtime system postpones the processing of read or write request of the symbolic client until no IEC task is executed. As soon as this gap is found, the restart of IEC tasks is postponed until the requested values have been copied to the variables list.

This option is useful for permanently running systems without production clocking, for example, if process values are to be written cyclically in fixed time intervals (such as 60 s).

NOTE: Do not activate the option Configure synchronisation with IEC tasks... for motion and real time-critical application because the delayed start of IEC tasks leads to a higher jitter.

If you intend to use the Configure synchronisation with IEC tasks... option, consider the following points when you define the variable lists that are read and written:

Configure synchronous and consistent access only for those variables for which it is necessary.
Create separate lists for consistent variables and for variables that may be inconsistent.
Create several small lists containing consistent variables instead of one large list.
Define the time intervals for cyclically reading values as large as possible.

The option Configure synchronisation with IEC tasks... is available at two different locations in EcoStruxure Machine Expert:

In the Symbol configuration editor, as an option of the Settings button. (If a symbol configuration is available in the application.)
In the Options tab of the Properties dialog box of the selected controller.

NOTE: In order for the setting to take effect, perform a Download or Online Change of the applications on the controller and update the boot applications.