Explanation of the oneshot command ([ons]) in RSLogix5000

[Lucifre]

Can someone explain to me oneshot command ( [ons] ) in Rslogixs5000 and why is it used in ladder logic for latch circuits even though its not necessary?

Added after 2 minutes:

Also, if you could point me to some online resources describing this command... the help in RS logix is really mysterious as to what this command really does

 

[abc2008]

Re: RSLogix5000 help

If a ladder line with ONS is turned on, the output coil receives just one pulse. It functions is very useful with math operations.
Imagine you want add 5 to a register each time a sensor detects a product. If you just put the contact (XIC) and the CPT or ADD function, each product detection will result in several ADD execution, but if you use ONS, each product detectio will result in just one ADD execution.
In latch logic is useful to avoid situations when the SET and RESET conditions are both active.