I have my first competition this week which uses vex field controllers. Is there anything I should know about it, or anything I need to do in advance.
I am assuming you mean V5 Smart Field Controllers (each event will state if they are using old style VEXnet or V5 Smart Field Control). You will find documentation about the V5 Smart Field Controller in the Documents tab of the event you are attending on RobotEvents.com. I am putting the link here which helps all teams prepare for the gear:
https://v5rc-kb.recf.org/hc/en-us/articles/9628304194711-Smart-Field-Control-for-Teams
That said, you should make sure you have latest VEXOs firmware loaded on your V5 Brain (as of 10/30/2024 that is 1.1.5) and that your software uses the competition template during development. This will allow the field to control your robot about competition state - disabled, autonomous, and drive control.
For old style VEXnet you will connect your V5 Joystick controller using the RJ45 jack in the middle. V5 Smart Field control uses V5 Smart Cables that should only be plugged into the two smaller jacks, if you try to put the V5 Cable in the center RJ45 port you may short wires in the connector, or have incorrect voltage applied to internal circuitry that may damage your V5 Joystick Controller.
My recommendation is to approach one of the event volunteers to show you how to connect your robot to the field correctly before matches start…
Have fun at your first competition!