The PLCs or programmable logic controllers from the GE Fanuc Series 90-30 comprise several modular components that are connected to form a complete control system that can be custom tailored for different industrial applications. The components that make up GE Fanuc Series 90-30 PLCs include the baseplates that most of the other components are mounted on, the power supplies with various ratings that are always mounted in the left-most slots in the baseplates, the CPUs or central processing units that monitor the PLCs functions and scan the controller for problems, the I/O modules that let the PLCs connect to input and output devices like switches and relays, the option modules that allow the PLCs to have networking and communication options, and the cables that can connect the PLCs to other machines, including other PLCs.

The GE Fanuc Series 90-30 PLCs should be mounted inside enclosures to protect them from common industrial hazards such as oil, dust, debris, vapors, and moisture. Their baseplates can have 5 slots or 10 slots depending on how many components will be assembled in a particular PLC and on what particular applications the PLC is intended for. Different baseplates also have different cabling distances ratings, and cabling distance is the maximum length that a cable between a given baseplate and the CPU baseplate. For example, Series 90-30 PLCs with Expansion baseplates have cabling distances of 50 feet, PLCs with Remote baseplates have cabling distances of 700 feet, and different Series 90-30 communication option modules can support cabling distances of 4000 feet or 75 feet. Modems and transmitters can also be used and these devices have nearly unlimited communication distance ratings.