Dear experts,

The turn table makes its stroke from 0 deg. to 180 deg. and from 180 deg. back to 0 deg.

0 deg. is the home position where it waits for some material to be loaded and 180 deg. is its destination position where it is going to deliver this material.

In case of main power outage & then resumption of power, how to make sure that the turn table doesn't starts to turn automatically (if it was between 0 deg. and 180 deg. when main power failed) to avoid any accidents?

What are the possible scenarios or factors to be considered in such applications in context of safety based on your experience(s)?

And ifthere is a production count (say by using counter "CU" named "C7" of S7 program in ladder logic) for the number of materials handled by this turn table, how to make sure that the program will not count twice for the same material after power resumption??

Regards

nbk

In case of main power outage & then resumption of power, how to make sure that the turn table doesn't starts to turn automatically (if it was between 0 deg. and 180 deg. when main power failed) to avoid any accidents?

nbk

What are the possible scenarios or factors to be considered in such applications in context of safety based on your experience(s)?

nbk

And ifthere is a production count (say by using counter "CU" named "C7" of S7 program in ladder logic) for the number of materials handled by this turn table, how to make sure that the program will not count twice for the same material after power resumption??

Thanks for the reply Fritz.

@ Fritz : " .......... supress counting by using flags and/or timers that are activated upon PLC restart (e.g set in startup OB's, reset when startup completed or acknowledged)."

Actually, that's what I'm looking for but unable to reach a solution.

Can that be done using OB100,OB1? For s7-400 and s7-300 as well?

Can I request you to be little more specific if you don't mind?

Regards