2 Industrial Communications Terminology

Unfortunately, different protocols use different terminology to reference the two types of devices attached to a industrial network. For example, EtherCAT uses the terms main and sub-device while EtherNet/IP uses scanner and adapter. Texas Instruments (TI) uses the terms Controller and Device throughout this paper.

An industrial communication network typically has a single Controller whose job is to mange and control the various network Devices. Process data is continuously exchanged between the Controller and network Devices and is used to make real-time process control decisions as well as longer term process optimizations. The Controller can perform advanced analysis of the process data, utilizing machine learning algorithms or can simply issue commands based on simple analog or digital feedback from the field Devices. An example of an advanced Controller function is multi-axis motion planning of a robotic arm whose motion is controlled via multiple servo motors (Devices).

From a hardware perspective, Controllers run on standard compliant Ethernet ports while Devices typically require special Ethernet hardware.