one more power question

can i use external 24vdc power supply to power 24vdc micrologix 1400 and use same power to power input sensor? Thank you for patience.

Yes

Yes, but when you say "same power", I assume you mean two circuits connected to the same power source. For those two circuits, you may want to use two different sizes of fuses, so then each circuit is not exactly the "same" power because each will carry a different current level.