suggest me the circuit for providing 24v output from plc to arduino uno input. voltage divider is risky or not and suggest any other ckt if any
Why do you think a potential divider is risky? Is this a digital voltage or an analogue one?
If digital what is the maximum frequency it will switch at? You could use an opto isolator if you want isolation and the maximum frequency is not too high.
A potential divider is only 'risky' if it is poorly designed and or constructed.
If you use appropriate resistor values and solder the resistors in place, then there should be no problem.
Don't rely on the contacts of a solderless bread-board in an industrial environment.