Comtrol DeviceMaster EtherNet/IP-Modbus EIP-MOD User Manual page 15

Term
Modbus/RTU
Modbus/ASCII
Modbus/TCP
Polling
Ethernet TCP/IP
DeviceMaster EIP-MOD User Guide: 2000664 Rev. A
The standard Modbus messages, in hexadecimal format, that are typically
transmitted over serial lines but can also be transmitted over other
communication methods such as wireless or Ethernet TCP/IP socket
connections.
Note: Modbus/RTU over Ethernet TCP/IP is not the same as Modbus TCP.
An ASCII, or character based, form of Modbus. The base message is the same as
Modbus/RTU, but the format is somewhat different.
An Ethernet based form of Modbus communication. The base message is the
same as Modbus/RTU, but a special Modbus header is included for packet
identification and routing purposes.
The process where a PLC or Application requests data on a continual basis. In
this operation the Master sends the request messages while the Slave responds
to the messages.
A form of Ethernet connectivity that provides a level of guaranteed delivery and
data verification. This is used for many upper layer protocols such as Modbus/
TCP and can be also used for transferring Modbus/RTU and Modbus/ASCII.
messages.
Definition (Continued)
Terms and Definitions
Chapter 1. Introduction - 15