GE RX3i

Chapter 6. Programming EGD Commands
96 PACSystems* RX7i & RX3i TCP/IP Ethernet Communications User Manual GFK-2224Q
6.5 Read PLC Memory (4000)
The Read PLC Memory command can be used to read memory locations from a remote PACSystems PLC. This
command does not require configuration of a produced / consumed exchange in the PLCs. The Read PLC
Memory command can only be sent to an individual IP Address; it cannot be sent to a Group ID (multicast).
Read PLC Memory Command Block
Word Offset
Value
Description
Word 1
Length of command data block
Always 16
Word 2
0
Always 0 (no-wait mode request)
Word 3
(See previous page)
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
4000 (fa0H))
Read PLC Memory command number.
Word 8
Retry time, in milliseconds
The time between retries of command transfers. Default
is 1000ms.
Word 9
Local read buffer memory type
Memory type for the data to be placed in the local PLC.
Word 10
Local read buffer reference table
starting address (least significant
word)
1-based offset in the local PLC
Word 11
Local read buffer reference table
starting address (most significant
word)
Word 12
Remote read location memory type
Memory type from which data will be read in the remote
PLC
Word 13
Remote reference table read
location starting address (least
significant word)
1-based offset in the remote PLC
Word 14
Remote reference table read
location starting address (most
significant word)
Word 15
Remote reference table length (in
remote memory units)
Number of remote memory units to be read.
Word 16
Network address type
Must be 1. Indicates an IP address will be used.
Word 17
Network address length
Must be 4 for IP address.
Group ID (multicast) is not permitted.
Word 18 –
Word 21
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 22
Reserved
Always 0
13
Word 4 (COMMREQ status word address) is the only zero-based address in the Command Block. This value
alone requires that 1 be subtracted from the intended address.