How to calculate the eight time parameters of et lt es ef ls lf tfff?

Use forward calculation (from the beginning of the project to the end of the project)

ES = Latest EF (EF of all immediately preceding active projects)

LS、LF:

Reverse calculation (from the end of the project to the beginning of the project)

Lf = early (LS of all the following active projects)

Total time difference: Float=LF-EF=LS-ES.

Calculation method

(1) For the work with the end node as the completion node, the total time difference should be equal to the difference between the planned construction period and the earliest completion time of the work.

(2) The total time difference of other operations is equal to the minimum value of the total time difference of its immediate operation plus the sum of the time interval between the operation and the immediate operation.

Total time difference. The calculation formula in the textbook is the minimum value of the sum of the total time difference of the double code time scale network diagram = the total time difference of the next job+the time interval between this job and this next job.

Baidu encyclopedia-total time difference