This tutorial will teach you about each of the components in a FRC control system. For each component, I will describe its role in a robot’s electrical system and how it connects to other components.
This tutorial was made through the Autodesk FIRST High School Intern program.
A willingness to learn
Step 1: Terminology
- Digital Signal: A digital signal has only two states: on or off. Robot components that communicate with a digital signal generally do so by varying the frequency at which they alternate between on and off.
- Analog Signal: Unlike a digital signal, which has discrete values, an analog signal’s output has a continuous range of values. Robot components that use analog signals communicate by varying the voltage of the signal.
- PWM Cable: A Pulse-Width Modulation (PWM) cable is a cable commonly used to allow robot components to communicate with each other, using either digital or analog signals. Most commonly, they have three wires, but there exist versions with anywhere from one to 5 cables.
- CAN: In FRC, a Controller Area Network (CAN) is used to control motor controllers. Several motor controllers are connected serially to the same network and then controlled from the central processor.
- Encoder: An encoder is a sensor used to measure rotation. It uses a digital signal to communicate that the shaft it is attached to has rotated a certain amount – “1 count.” The number of counts per full revolution varies between encoders, but can be anywhere from one to one thousand per revolution.