For simple data acquisition tasks, Arduino represents an affordable and accessible platform. You can easily link your sensors to the analogic and digital I/Os.
Then to get your connection between Scilab & Arduino, try out this tutorial
Here is a simple circuit for temperature acquisition directly controllable from Scilab & Xcos:
To set it up, here is a tutorial for entry level test & measurement with Arduino:
And for soft-real time Hardware in the Loop, you can even design your motor controller in Xcos as displayed here:
Finally check out this video from a member of our community: