Many industrial systems contain networks of sensors, actuators and processors. A robot is an integration of all of these devices and the robot probably has some kind of connection to the rest of world so that it can be re-programmed. The Industrial Internet of Things (IIOT) makes it possible for devices to be converged in ways that could not be in the past.
Consider an office building. The elevators, HVAC, lighting, security and many more systems exist but do not talk to each other. Efficiencies can be made in the office if they were coordinated. As an example, when an employee swipes their badge at the front door, the elevator knows that they will be required to take them from the ground floor to their office and can schedule its arrival for maximum efficiency along with all other pending requests. Heating, lighting and other functions can be informed so that all necessary lights are on and the office set to the desired temperature. The elevator is also monitoring itself and instead of having to undergo regular maintenance, will inform the necessary people when parts are getting worn, or if some other maintenance function is required.
The IIOT is characterized by long lived assets that have high value. They are meant to have very limited interaction with human beings once installed and they have some critical requirements related to zero failures, resilience and hardened security. The IIoT is often a very hostile environment, especially with regards to the communications, so issues such as SNR, and dynamic range have to be addressed.
Some edge devices may exist within hostile environment, meaning that temperature ranges may be extended or they may have to operate in toxic environments.
The IIOT is generally referred to as a brown field environment, as opposed to green field. Brown field means that the application area is not new and that many of the IIOT devices will replace existing devices. Infrastructure, such as wiring may already be in place and this may be necessary due to reliability requirements that could not be met by wireless communications.
Connectivity standards may already be in place.