The ROS node for motor controller of wheeled mobile robots. The device was described in link below. http://mdrwiega.com/2016/05/11/dc-motors-controller-for-mobile-platforms-with-ros-support/
The showed node allows to communicate with device. It publishes the odometry data, digital inputs states and subscribes velocity commands, digital outputs states.
The picture shows a hardware device.
The diagram shows a structure of a node.