Read Egd Exchange (4002); Read Egd Exchange Command Block - GE RX3i User Manual

Read EGD Exchange (4002)

6.7
The Read EGD Exchange command can be used to read some or all of a configured Ethernet Global Data
exchange from either the producer or the consumer. This command identifies the data to be read using its
configured Producer ID and Exchange ID. It can then read the content of the data for the exchange, directly
from the producer or consumer device memory. This command can be sent to PACSystems PLCs and to other
EGD Class 2 devices. In a PACSystems PLC, reading an EGD exchange reads the PLC reference memory
locations configured to be transferred at the specified offset in the exchange. Thus current process data will be
read, not the data that was transferred last in the exchange.

Read EGD Exchange Command Block

Word Offset Value
Word 1 Length of command data block
Word 2 0
Word 3 (See table on page 95)
Word 4 0-based
Word 5 0
Word 6 0
Word 7 4002 (fa2H)
Word 8 Retry time, in milliseconds
Word 9 Local read buffer memory type
Word 10 Local read buffer reference table starting
address (least significant word)
Word 11 Local read buffer reference table starting
address (most significant word)
Word 12 Remote signature
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)
Word 16 Remote Exchange ID (most significant
word)
Word 17 Remote Exchange Offset
Word 18 Read length
Word 19 Network address type
Word 20 Network address length
Word 21 to IP Address of the remote PLC
Word 24
Word 25 Reserved
GFK-2224Q
13
Chapter 6. Programming EGD Commands
Description
Always 19
Always 0 (no-wait mode request)
Memory type of COMMREQ Status Word
Offset of COMMREQ Status Word
Reserved
Reserved
Read EGD Exchange command number.
The time between retries of command transfers,.
Default is 1000ms.
Memory type for the data, in the local PLC.
1-based offset
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.
EGD Exchange ID
Byte offset (0-based) in the exchange that should
be read.
Number of bytes to be read in the range 0 to 1400
bytes.
Must be 1. Indicates that an IP address will be
used.
Must be 4 for IP address. Group ID (multicast) is
not permitted.
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.
Always 0
January 2017 101