How can we define BC for a determined degree of freedom in only one direction

Hi Abaqus users:

 

I am trying to define for a simple FE model of a Platte a displacement BC on a surfece (in the direction normal to this surface), but ONLY in one direction (like if it wer a contact) but I do not want to use a secundary body to do it. Is there in Abaqus an easy way to do it (withot programming, scripts,...)?

 

Thank you for your help!