Creating or editing OLT-fields in FBD

How to create →OLT-fields in the →graphical FBD-editor :

1. Select the element for which you want to create the OLT-field, open the context menu and select Create and OLT-Field. Alternative: Select the element and press the o-key.
   

   For which elements is it possible to create an OLT-field?

   The following principles are valid:

   • Within the FBD-editor for →programs or →function blocks, an OLT-field can be created for elements that have a value during the execution on the →PLC.

   • Within the FBD-editor for →functions, an OLT-field cannot be created at all.

   If the creation of OLT-fields is possible within the FBD-editor, it is possible ( ) or not ( ) to create an OLT-field for the following elements:

   Element	An OLT-field can be created.
   a →value field containing a declared →variable
   another value field (e.g. with a constant literal)	Restriction: At present, no values are displayed within such OLT-fields.
   an input or output of a →function block instance
   a function block instance itself
   a FORCEMRK block An OLT-field for a FORCEMRK block differs from an OLT-field for the other elements (see examples under "OLT-fields for force marker"
   an output of a →call of a →function	Restriction: These OLT-fields display a value in case of the logi.CAD 3 default scope. If e.g. a system integrator has deactivated the d ebugging feature for FBD, the OLT-fields for function outputs do not display a value.
   an input of a →call of a →function
   a function itself
   an SFC-element In particular, for the following part of the SFC-element: the step marker output of a→step the input for the transition condition of a →transition the input and output of an →action block	Restriction: At present, no values are displayed within the OLT-fields for SFC-elements.
   →connector and →continuation

2. Position the OLT-field where you need it.

3. Press the primary mouse button.
   During this user action, it is possible that affected lines are automatically rerouted. If the positioned element is presented with a red rectangle, the destination is not possible. Press the ESC-key, if you do not want to position the element and abort the action.
   Result:

   • If the FBD-editor has been opened without →instance context, just an empty OLT-field is displayed.

   • I f the FBD-editor has been opened with instance context, the OLT-field displays the value for the associated element. If you want to change the value of the element, this is possible as follows:

     Type of OLT-field	Step
     For a normal OLT-field	Double-click onto the OLT-field and enter a new value in the dialog. This dialog is identical to the one you are using to change the values within the Values of Variables view. Details: see "Changing the values of variables: writing values to PLC". For →character string literals the following is additionally valid : Do not delete the leading/terminating quote character within the input field (these quote characters are not displayed in the OLT-field itself for a STRING-variable but they are needed when entering the value).
     For an OLT-field for a force marker	Double-click the upper part of the OLT-field and enter a force value in the dialog This dialog is also identical to the one you are using to change the values within the Values of Variables view. Click onto the force switch (the slider) of the OLT-field in order to write the force value onto the PLC. Result: The force switch is displayed as . The lower part of the OLT-field displays the force value. If requested, click again onto the force switch in order to write the actual value onto the PLC. Result: The force switch is displayed as . The lower part of the OLT-field displays the actual value.

If the OLT-field has been created for a →function block instance or i f the variable or the in-/output is declared based on a →structured data type or an →array data type, this is how you are able to enter one of its sub-elements within the OLT-field (see the example under OLT-fields in FBD"):

1. Open the context menu for the OLT-field and select Edit OLT-Field. Alternative, if the FBD-editor has been opened without →instance context:: Double-click the OLT-field .

2. The following possibilities are provided – depending on the source of the OLT-field:

   Structured data type	Use the content assist: Enter one or more letters. This displays a list with all elements fitting your input. Example: Enter scale . The list provides all structure elements containing the text scale . Click an element in the list or select it (by using the mouse or the cursor movement keys) and press the Enter-key .
   Array data type	Enter the array index, e.g.: [1] If you enter the character [, you get a list of all possible array indices.
   Function block instance	Use the content assist: Enter one or more letters. This displays a list with all elements fitting your input. Example: Enter scale . The list provides all variables of the function block instance containing the text scale . Click an element in the list or select it (by using the mouse or the cursor movement keys) and press the Enter-key .

3. Press the Enter-key or click anywhere outside the OLT-field so that the sub-element is entered. Press the ESC-key, if you want to discard the sub-element.
   If the OLT-field is highlighted as faulty, the sub-element is causing an error. Enter another sub-element.