Terms And Definitions - Comtrol DeviceMaster EtherNet/IP-Modbus EIP-MOD User Manual

Terms and Definitions

1.5.1. Terms and Definitions
This section uses the following terms and definitions.
Term
Class 1
Class 3
EtherNet/IP
Ethernet TCP/IP
Ethernet UDP/IP
Multicast
Point-to-Point
Master (or Client)
Mode
Slave (or Server)
Mode
Device ID
Device ID Offset
Received Device ID The original device ID received in the Modbus message from a Modbus master.
Alias Device ID
Local Slave Device
Remote Slave
Device
14 - Chapter 1. Introduction
Otherwise called implicit messaging, is a method of communication between
EtherNet/IP controllers and devices that:
• Uses Ethernet UDP messages.
• Is cyclic in nature. Input and/or output data is exchanged between the
controllers and devices at regular time intervals.
Otherwise called explicit messaging, is a method of communication between
EtherNet/IP controllers and devices that:
• Uses Ethernet TCP/IP messages.
• By itself is not cyclic in nature. The controller and devices must send
individual messages to each other.
An Ethernet based industrial communication protocol utilized to communicate
between controllers, often times PLCS, and devices.
Standard Ethernet communications protocol utilizing socket communication
interfaces that guarantees delivery to the intended device.
Standard Ethernet communications protocol utilizing socket communication
interfaces that does not guarantee delivery. The data may or may get to the
intended device.
Multicast addressing involves Ethernet devices sending messages to each other
using a multicast address. Multicast addressing:
• Uses a specified IP address range designated for multicast communication.
• Allows either one or multiple devices to receive the same messages.
Point-to-Point, otherwise called unicast, addressing involves Ethernet devices
sending messages directly to each other using their own IP addresses. Messages
are sent to only one device.
The method of operation when a PLC, a gateway, or an application is operating
as a Master or the message originator.
The method of operation when a PLC, a gateway, or an application is operating
as a Slave or the message receiver.
The Modbus device identification number. Device IDs include:
• 0 = Broadcast
• 1-247 = Standard device IDs
• 248-255 = Reserved device IDs (generally used for vendor specific gateway
functions)
An offset applied at the slave serial port interface that changes the message
device ID range to match the serial device(s) device ID range.
The device ID that the original received ID is changed to when an Alias Device
ID is configured.
A local slave device is one that is connected directly to a serial port on the
gateway.
A remote slave device is either a slave Modbus/TCP device or a serial slave
device attached to another gateway and accessed as a remote Modbus/TCP
device.
Definition
DeviceMaster EIP-MOD User Guide: 2000664 Rev. A