GE PACSystems RX7i, User Manual

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Chapter 6. Programming EGD Commands
104 PACSystems* RX7i & RX3i TCP/IP Ethernet Communications User Manual GFK-2224Q
6.8 Write EGD Exchange (4003)
The Write EGD Exchange command can be used to write portions of a configured Ethernet Global Data
exchange in a remote producer node. EGD protocol prohibits writing to a consumed exchange. This command
identifies the exchange to be written using its configured Producer ID and Exchange ID. It can then write the
content of that data directly to the device memory. This command can be sent to PACSystems PLCs and to
other EGD Class 2 devices. In a PACSystems PLC, writing an EGD exchange modifies the PLC reference memory
locations configured for transfer at the specified offset in the exchange. Thus current process data will be
updated, not the data that was transferred last in the exchange.
Write EGD Exchange Command Block
Word Offset Value Description
Word 1 Length of command data
block
Always 19
Word 2 0 Always 0 (no-wait mode request)
Word 3 (See table on page 95) Memory type of COMMREQ Status Word
Word 4 0-based
13
Offset of COMMREQ Status Word
Word 5 0 Reserved
Word 6 0 Reserved
Word 7 4003 (fa3H) Write EGD Exchange command number.
Word 8 Retry time, in milliseconds The time between retries of command transfers. Default is
1000ms.
Word 9 Local write buffer memory
type
Memory type for the data, in the local PLC.
Word 10 Local write buffer reference
table starting address (least
significant word)
1-based offset
Word 11 Local write buffer reference
table starting address (most
significant word)
Word 12 Remote signature EGD Exchange signature. This should be 0 for PLCs when not
using signatures. If run-mode store of EGD will be used, the
use of signatures is highly recommended.
Word 13 Remote Producer ID (least
significant word)
EGD Producer ID
Word 14 Remote Producer ID (most
significant word)
Word 15 Remote Exchange ID (least
significant word)
EGD Exchange ID
Word 16 Remote Exchange ID (least
significant word)
Word 17 Remote Exchange Offset Byte offset (0-based) in the exchange that should be read.
Word 18 Write length Number of bytes to be written in the range 0 to 1400 bytes.
Word 19 Network address type Must be 1. Indicates an IP address will be used.
Word 20 Network address length Must be 4 for IP address.
Group ID (multicast) is not permitted.
Word 21 to
Word 24
IP Address of the remote PLC Four integers, specified as one integer per word of the dotted-
decimal IP address of the remote PLC. May not be a group IP
address.
Word 25 Reserved Always 0