Type IODDT instance

The data types (structures) have been predefined by the manufacturer and contain I/O language objects belonging to the channel of an application specific module (or the module itself).

Perform the following steps to create an IODDT instance:

Step

Action

1

Select the Variables tab in the data editor.

2

Double-click on the empty cell Name (marked with an arrow) and enter the name of the instance.

3
Double-click on the corresponding Type field and click on it
.

The following window appears.

4

In the Library/Family area, display the <Catalog> index.

The following window appears.

5

Select the Type of Controller, Function and the corresponding IODDT Type.

Confirm with OK.

Example: Instance ENTRY_PRESSURE of Type T_ANA_IN_BMX:

Linking to the application specific module

Step

Action

1

Select the Variables tab in the data editor.

2

Enable the IODDT checkbox, which will display instances of Type IODDT.

3

Select the IODDT instance based on which the link will be created.

4

Enter the address of the module or its future storage location in the Address column (it is not necessary to configure the module during this phase).

Example:

Rules

Follow the rules below:

  • An IODDT data type cannot be nestled in a DDT data type.

  • An IODDT data type cannot be nestled in another IODDT data type.

  • A public or private variable of a DFB cannot be an IODDT type.

  • An input / output parameter of a DFB may be of Type IODDT. However, you can only use those IODDT types that are listed in the Variable Type Selection menu.

  • An IODDT instance cannot be accessed from a DFB section.