Descriptions of the event processing blocks (E_DELAY, etc) are in
Annex A of IEC 61499-1.
The block that does what you are looking for is E_CHRON (chronometer,
i.e., stopwatch) in the src/events folder. Open it in the FBDK, read
the description, and run it in the test window to see how it works.
HTML (*.htm) files containing documentation of many of the blocks in
the FBDK download are in the /doc directory and its subdirectories.
One place to find much of this information is the "Design Patterns"
item of the "Help" menu.
Descriptions of many blocks and how to use them are in Prof Vyatkin's
book available from ISA. See
http://www.isa.org/Template.cfm?Section=Books3&template=/Ecommerce/ProductDisplay.cfm&ProductID=9216
- Jim C