Calculating m/min and set point min/meter in logo: set up the same system but with a limit switch

Hello

In this summer i put this system which count the speed with a encoder (see the programm adove) and control the speed with a valve,the system has worked perfect.Now I a m trying to set up the same system but with a limit switch,i mean i have only one pulse to calculate the real meter per minute.

For this purpuse i measuring the time interval between pulses,(can you see this in the attachemnt programm) ,the radious is 5cm,and after the count ,calculate the meter per minute ...

I would like to see the programm and i  want your comment if i am right with this way.

------------------------------------------------------------------------------------------
Split from Calculating m/min and set point min/meter in logo.

Hello everyone

Any suggestion or comment about this i had make with one limit switch?Its the right way ?

Hello 

Any objection about the meaure speed with one pulse?Also i have seperate the code for this purpose,i am waiting your comment about that