Which driver must be running and configured to enable an OC to communicate with a CompactLogix PLC on an Ethernet network?

The correct answer is EtherNet/IP, as this is the specific protocol used for communication with Rockwell Automation's CompactLogix PLCs over Ethernet networks. EtherNet/IP is built on the Common Industrial Protocol (CIP) and is designed to facilitate reliable and efficient data transfer between devices on an Ethernet network. This protocol allows for real-time control and monitoring of industrial automation devices, making it essential for operations involving CompactLogix PLCs.

Understanding the role of EtherNet/IP is critical because it defines how various devices, such as controllers and other industrial equipment, share data in a standardized manner. When properly configured, the handshaking and data encapsulation processes specific to EtherNet/IP ensure that devices can communicate seamlessly, supporting the requirements of Industry 4.0 applications where fast and reliable communication is essential.

While TCP/IP underpins the basic network communication by defining how data packets are sent and received over a network, it does not provide the structured communication framework necessary specifically for interacting with CompactLogix PLCs. Other protocols like Modbus TCP and CANopen serve different industrial communications needs and are not compatible with Rockwell's EtherNet/IP, which underscores the importance of selecting the appropriate driver for successful device communication in this context.