EtherNet/IP Protocol Principles

Overview

This section describes how to use the LTMT main unit over an EtherNet/IP communication protocol network.

WARNING
LOSS OF CONTROL The designer of any control scheme must consider the potential failure modes of control paths and, for certain critical functions, provide a means to achieve a safe state during and after a path failure. Examples of critical control functions are emergency stop and overtravel stop. Separate or redundant control paths must be provided for critical control functions. System control paths may include communication links. Consideration must be given to the implications of anticipated transmission delays or failures of the link. For additional information, refer to NEMA ICS 1.1 (latest edition), Safety Guidelines for the Application, Installation, and Maintenance of Solid State Control. Each implementation of the LTMT main unit must be individually and thoroughly tested for proper operation before being placed into service. Failure to follow these instructions can result in death, serious injury, or equipment damage.

WARNING

LOSS OF CONTROL

The designer of any control scheme must consider the potential failure modes of control paths and, for certain critical functions, provide a means to achieve a safe state during and after a path failure. Examples of critical control functions are emergency stop and overtravel stop.
Separate or redundant control paths must be provided for critical control functions.
System control paths may include communication links. Consideration must be given to the implications of anticipated transmission delays or failures of the link. For additional information, refer to NEMA ICS 1.1 (latest edition), Safety Guidelines for the Application, Installation, and Maintenance of Solid State Control.
Each implementation of the LTMT main unit must be individually and thoroughly tested for proper operation before being placed into service.

Failure to follow these instructions can result in death, serious injury, or equipment damage.

WARNING
UNEXPECTED MOTOR RESTART Ensure that the PLC application software handles: Forced start command. Mode change from local to remote. Motor control commands during transition from local to remote. Multiple Modbus client with undefined control management. Failure to follow these instructions can result in death, serious injury, or equipment damage.

When you switch to the network control channels, the LTMT main unit checks the communication protocol configuration. It then uses the latest known motor control commands from the PLC to automatically restart the motor.

EtherNet/IP is an application layer protocol treating devices on the network as a series of objects. It is an implementation of the Common Industrial Protocol (CIP) over TCP/IP.

The network carries control data and the properties of the device being controlled. It enables you to operate either in a client/server or a peer-to-peer mode.

The messages can be exchanged through:

I/O messaging: dedicated to exchanges of process data. It is also called as class one messaging or implicit messaging.
Explicit messaging: dedicated to exchanges such as configuration, settings, or diagnostics data. It is also called as class three messaging.