ProSoft Technology MVI69-EGD - Manual (Page 77)

Reference MVI69-EGD ♦ CompactLogix or MicroLogix Platform
GE Ethernet Global Data Communication Module
ProSoft Technology, Inc. Page 77 of 96
November 3, 2008
5.2.3 EGD Data Producer
The EGD driver will generate produced data as defined in the user configuration
exchange list. This data is derived from the module's internal database and is
produced at the set frequency defined in the exchange list. This data can be
broadcast to all nodes or to a specific node on the network. Up to 700 database
registers can be transferred in a single produced message. Therefore, to transfer
the whole database would only require 6 messages (4000 word registers in the
module's database).
Central to the functionality of the module is the internal database. This database
is shared between all the drivers in the module and is used as a conduit to pass
information from one device on one network to one or more devices on another
network. This permits data from devices on one communication port to be viewed
and controlled by devices on another port.
The producer functionality provided in the EGD driver is used to transfer portions
of the module's database to other EGD nodes on the network. The following
diagram describes the flow of data between the producer, the internal database
and the remote EGD devices:
5.2.4 EGD Data Consumer
The EGD driver will consume 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. Exchanges
received by the consumer driver that are not defined in the exchange list will be
discarded. Up to 700 words of data can be consumed in a single message.
Therefore, to fill the whole database with values would only require 6 exchanges
(4000 word registers in the module's database).