ProSoft Technology MVI69-EGD - Manual (Page 61)

Reference MVI69-EGD ♦ CompactLogix or MicroLogix Platform
GE Ethernet Global Data Communication Module
ProSoft Technology, Inc. Page 61 of 96
November 3, 2008
Code Description
34 Write Request
35 Write Response
36 Masked Write Request
37 Masked Write Response
The producer functionality provided in the EGD protocol is used to transfer
portions of the module's database to other EGD nodes on the network. The
consumer functionality is used to transfer data from other nodes on the network
into the module's database.
The EGD module generates produced data as defined in the user configuration
exchange list, from the module's internal database, and is produced at the
frequency defined in the exchange list. This data can be broadcast to all nodes or
to a specific node on the network.
The EGD module consumes data as defined in the user configuration exchange
list. This data is derived from other nodes on the network and is placed in the
module's internal database. If a consumer exchange is not received at the
specified timeout, the driver will update the status of the exchange. When the
driver again receives the exchange, the status will be updated.
5.2 Functional Overview
GE Fanuc Automation and GE Drive Systems developed an Ethernet Global
Data, or EGD, exchange for PLC and computer data in 1998. GE Ethernet Global
Data (EGD) offers versatility where a mix of control devices requires cooperation
with each other. This involves sharing of information across the applications
regardless of device or network type, often at high speed, and with high
reliability. Bandwidth utilization is optimized by using efficient communication
methods. High reliability means fewer communication failures and having the
ability to detect failures upon occurrence. Particular emphasis is delivered for
applications requiring periodic or frequent updates and time synchronization of
devices. The protocol supports Unicast, Broadcast and Multicast group
messaging. Efficiency is based on the fact each device on the network can
produce these types of messages and each device determines which of these
messages to consume.
5.2.1 Ethernet Global Data Compatible Devices
List of devices that support the Ethernet Global Data protocol:
ƒ GE Series 90-70 PLC CPU (CMM742 with EGD support)
ƒ GE Series 90-30 PLC CPU 364 (with EGD support)
ƒ VersaMax
CPU E05
ƒ Several drives and turbines
ƒ Ethernet Global Data Service for NT
ƒ CIMPLICITY HMI software
ƒ Several HMI products