Computed attributes - Trip Duration

Dears,

How can I calculate the trip duration by computed attributes ?
I have tried to get difference bet. deviceTime and oldDeviceTime but it dose not work as prober.

Many Thanks in Advance

Please don't duplicate your questions.

Many Thanks Anton,

Please send me the duplicate post link. I submit another post but i dont find it in the topics list i dont know why.

https://www.traccar.org/forums/topic/server-time-in-the-calculated-attributes/#post-97483