This diagram is a bit messy, but it is fully legal. You see local variables in top, left corner. You see PLD State symbols in green and Magneta, You also see addign and events used to execute if tests.
PLD State symbols originate from SDL (Specification and Description Language) that is popular in telecom and some other industries. This is in effect a “goto” – if you transfer control to CloseAndOpen you jump to the one that has an output event. In the case of CloseAndOpen you close the ComLink that will trigger OnClose that cause a delay of 500ms before it Re-Open Com.
Note: I would code this top-down (fixed events can be top-down or left-right) to make a cleaner diagram – but this is your choise. I also used a bit of colors to clarify the diagram in this case. But, this is the choise of the developer – the tool will not stop you from making messy diagrams if you want to.