FBD/LD/IL element function block
Symbol: 
A function block and its call can represent additional functions, for example IEC function blocks, IEC functions, library function blocks, operators.
A function block can have any inputs and outputs.
If the function block is associated with an image file, the function block symbol is displayed within the function block. A prerequisite is that the option Show function block icon is enabled in the TwinCAT options, category TwinCAT > PLC Environment > FBD, LD and IL.
If you have changed the function block interfaces, you can update the function block parameters with the command Update parameters in the menu FBD/LD/IL, without having to reinsert the function block.
See also: