The ES7510-XT supports Modbus TCP communications through the CLI, which does not support Modbus
ASCII or Modbus RTU. This functionality is not available on a web user interface page.

Modbus TCP is commonly used to communicate over TCP/IP networks, connecting over Port 502. Modbus
TCP is used in industrial automatic communications systems and has become a standard protocol for
industrial communications to transfer data to analog I/O devices or PLC systems.

Modbus TCP defines a simple protocol data unit independent of the underlying data link layer. The Modbus
TCP packet includes three parts:

•

MBAP header is used in the TCP/IP header to identify the Modbus application data unit. The MBAP
header also includes a unit identifier to recognize and communicate between multiple independent
Modbus end units.

•

Function code

•

Data payload

Modbus devices communicate using a master (client) /slave (server) architecture, only one device can initiate
a transaction and the others respond to the master/client. The other devices (slave/server) respond by
supplying the requested data to the master/client, or by taking the action requested in the query. The slave/
server can be any peripheral device that processes information and sends the output data to the master using
Modbus TCP protocol.

The ES7510-XT operates as slave/server device, while a typical master/client device is a host computer
running appropriate application software, for example, a SCADA / HMI system. The ES7510-XT can be polled