IEC-blocks for the application

The IEC-blocks are standard →functions and standard →function blocks provided by logi.CAD 3 and as described in the →IEC-standard or realized as enhancement to this standard.

The project within the project explorer contains the folder Standard listing all supported IEC-blocks. Do not manipulate the folder and its contents! If you do nevertheless, logi.CAD 3 does not find the library or the blocks any longer.

No check of invalid connections

For some blocks, invalid connections are not checked by logi.CAD 3. Therefore, enter code in your application to detect invalid connections (e.g. IF-statements). Example: An invalid connection occurs during a calculation using an IEC-block. Giving you a specific example: Calculating -250.5 by means of the EXPT-block is an invalid connection.
Invalid connections of blocks that are checked by logi.CAD 3 are listed in the description of the corresponding block.

If invalid connections are occurring while your application is executed, it is possible that:

  • Wrong results are calculated.
    Subsequently, these wrong values are displayed in the Values of Variables view. Remove the error in the ST-code so that there is no invalid connection anymore, then load the application anew onto the PLC.

  • The execution of the application terminates unexpectedly.
    Subsequently, no values for the application are displayed in the Values of Variables view. Remove the error in the ST-code so that there is no invalid connection anymore, then load the application anew onto the PLC.

  • The PLC terminates unexpectedly.
    Subsequently, no values for the application are displayed in the Values of Variables view and the Instances view displays state Offline. Restart the PLC, remove the error in the ST-code so that there is no invalid connection anymore, then load the application anew onto the PLC.

logi.CAD 3 supports the following →blocks according to the IEC-standard or as enhancement for it: