The GE-EGD (Ethernet Global Data) driver allows the FieldServer to transfer data to and from
devices over Ethernet using GE-EGD (Ethernet Global Data) protocol. There are two Ethernet
ports standard on the FieldServer. The FieldServer can emulate either a Server or Client.
GE Fanuc Automation and GE Drive Systems developed an Ethernet Global Data, or EGD,
exchange for PLC and computer data in 1998. EGD uses UDP or datagram messages for fast
transfer of up to 1400 bytes of data from a producer to one or more consumers. UDP
messages have much less overhead than the streaming TCP connection used for programming
or CommReq’s over SRTP Ethernet. Like Genius® broadcast input or directed control
messages, UDP messages are not acknowledged. They can be sent at short intervals.
Chances of one or more messages being dropped are small on a local area network.
As a client the FieldServer acts as an EGD consumer. As a master the FieldServer acts as an
EGD producer.
The IC697CMM742 Ethernet module supports both GE SRTP and GE EGD.
FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com
The FieldServer is connected to the Site Ethernet as shown below.
Configure and connect the "GE TCP/IP Ethernet Interface Type 2" according to manufacturer’s
instructions.
N7
Site Ethernet
FIELDSERVER
CONNECTION DIAGRAM
BASE NAME:
FILE NAME:
GE-EGD
(408)-262-2299
DATE: 2/4/04
BY: MF
FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com
Historically, one uses the client-server model to describe the operation of most protocols.
Recently producer-consumer model protocols have started to become more numerous. The
GE-EGD (Ethernet Global Data) is a producer-consumer model protocol. In equating the two
models it is important to regard the consumer as a passive (FieldServer) client. Other clients
typically are active and poll for new data. The consumer is a passive client in that waits to
digest new data generated by a producer.
For a detailed discussion on FieldServer configuration, please refer to the instruction manual for
the FieldServer. The information that follows describes how to expand upon the factory defaults
provided in the configuration files included with the FieldServer (See “.csv” files provided with
the FieldServer).
This section documents and describes the parameters necessary for configuring the FieldServer
to communicate with a GE-EGD Producer.
The configuration file tells the FieldServer about its interfaces, and the routing of data required.
In order to enable the FieldServer for GE-EGD communications, the driver independent
FieldServer buffers need to be declared in the “Data Arrays” section, the destination device
addresses need to be declared in the “Client Side Nodes” section, and the data required from
the servers needs to be mapped in the “Client Side Map Descriptors” section. Details on how to
do this can be found below.
Note that in the tables, * indicates an optional parameter, with the bold legal value being the
default.
4.1. Data Arrays
Section Title
Data_Arrays
Column Title Function Legal Values
Data_Array_Name Provide name for Data Array
Data_Format
Data_Array_Length
Provide data format. Each Data Array
can only take on one format.
Number of Data Objects. Must be
larger than the data storage area
required for the data being placed in
this array.
Up to 15 alphanumeric
characters
FLOAT, BIT, UInt16,
SInt16, Packed_Bit, Byte,
Packed_Byte,
Swapped_Byte
1-10,000
FieldServer Technologies 1991 Tarob Court Milpitas, California 95035 USA Web:www.fieldserver.com