• E_TimeStamp gives you a time stamp value every time you trigger the EI input event.
  
• E_StopWatch gives you the time duration that has elapsed between receiving a START and a STOP event
  

If you need to get the elapsed time you can use the function TIME() in an algorithm which will give you the time elapsed since the FORTE was started.

If you need higher accuracy a better approach would be to write an function block which is reading the system time from the operating system and translates it into a TIME_OF_DAY date type.

1. Although you can implement a pure scan-based architecture also in IEC 61499 you will loose a lot of the advantages you can get with events. Do you really need to do it in a scanned based way or wouldn't an event driven IEC 61499 approach bring you more benefits. En example for a potential architecture/deign pattern that can help you is presented in [1]. Especially in warehouse and intraprocess logistics (e.g., conveyor belts) most actions are event triggered (e.g., rising or falling edge of a sensor, command from higher level system).
   
2. Please note that when you want to measure time delays across different devices you need to apply some time synchronization means so that you can compare the time stamps.
   

Algorithm START in ST:
    startTime := TIME();

 Algorithm STOP in ST:
    DT :=  TIME()  - startTime;