I am a graduate Aerospace Engineering student. I need to wire a pneumatic actuator's controller and a magnetic position sensor for a small part of my research. I received a connection diagram from the company making the controller, and there is a relevant video showing the procedure on YouTube. Since I, unfortunately, don't remember anything from my electrical course years ago, I don't know what a particular component in the video is called. The connection diagram says PLC, but there does not seem to be any 'PLC' in the form I am vaguely familiar with, nor is there any programming involved in the video.
Video - https://www.youtube.com/watch?v=5lFFg6-doK0 (from 0:05)
What is that device in the center called? It just seems to transfer i/p-o/p