GE PACSystems RX7i Reference Manual page 196

RX7i
RX7i CPUs have an embedded Ethernet interface that provides TCP/IP communications with
programming software and other control systems. These communications use the proprietary SRTP
protocol and the standard Modbus/TCP protocol over a four-layer TCP/IP (Internet) stack. The Ethernet
interface also supports Ethernet Global Data protocol using UDP (User Datagram Protocol).
The embedded Ethernet interface has two RJ45 Ethernet ports. Either or both of these ports may be
attached to other Ethernet devices. Each port automatically senses the data rate (10 Mbps or 100 Mbps),
communication mode (half-duplex or full-duplex), and cabling arrangement (straight through or
crossover) of the attached link.
RSTi-EP
RSTi-EP_CPE100/CPE115 provides one or more embedded Ethernet interfaces. If used, each interface
connects to a Local Area Network (LAN).
The corresponding RJ45 Ethernet port(s) automatically sense the data rate on the attached LAN
(100 Mbps or 10 Mbps), as well as the corresponding communication mode (half-duplex or full-duplex),
and the corresponding cabling arrangement (straight through or crossover). Automatic detection greatly
simplifies installation procedures.
See RSTi-EP CPU Features and Specifications to determine the complete list of Internet protocols
supported by each CPU.
Some important protocols supported by all RSTi-EP CPUs are:
•
TCP/IP, which provides basic Internet capabilities;
•
SRTP, which is proprietary and which provides the interface with the PME programming and
configuration software and supports communications with certain control systems and
supervisory computer layers in the factory;
•
Modbus TCP, which supports the Modbus messaging structure over the Internet.
On the CPE100/CPE115, the same shared processor performs both Ethernet port processing and
Controller logic processing.
Each interface on a LAN must have a unique IP Address and a non-overlapping IP subnet. This is
configured in PME. Care must be taken to survey the entire connected network architecture in order to
tabulate the IP addresses and IP subnets already in use, both on the local networks and on any of its
routed subnets connected with a gateway. Never assign a conflicting IP Address or configure duplicate
IP subnets. For examples, please refer to section 5.1.1.1
GFK-2222AD
The two ports on the Ethernet Interface must not be
connected, directly or indirectly to the same device. The hub or
switch connections in an Ethernet network must form a tree;
otherwise duplication of packets may result.
April 2018
Chapter 5. Communications
Caution
185