According to various aspects, exemplary embodiments are disclosed of devices, systems, and methods related to controlling machines using operator control units and programmable logic controllers (PLCs). In an exemplary embodiment, a machine control system includes a machine, a programmable logic controller coupled to the machine, and an operator control unit. The operator control unit includes a user interface configured to receive one or more commands from an operator for controlling the machine, and a wireless interface configured to transmit a message based on the one or more commands received via the user interface. The programmable logic controller is configured to, in response to receiving the message transmitted by the operator control unit, transmit one or more control signals to the machine to control operation of the machine. The system does not include any machine control unit (MCU) separate from the operator control unit and the programmable logic controller.