E 71) – ProSoft Technology MVI69-EGD User Manual
Page 71
Reference MVI69-EGD
♦ CompactLogix or MicroLogix Platform
GE Ethernet Global Data Communication Module
ProSoft Technology, Inc.
Page 71 of 96
November 3, 2008
Read PDUs
PDU Type = 32
Read Request
The read request PDU is used to request the contents of one or more contiguous
groups of memory from a specific peer controller. The header defines parameters
which apply to the all of the individual cell references in the message. Each cell
reference specifies an offset into the specified Exchange or target-specific
address and the number of bytes to read. Based on the address type, the
Domain ID must contain an Exchange and Producer ID or target-specific address
which is valid on the destination node. A read request sent from a requesting
node must be followed by a read response message from the responding node.
Packet
Info
Description Data
Source Port:
7937 (0x 1F01)
Destination Port:
7937 (0x 1F01)
Length:
xx bytes (0x 00 XX)
Checksum:
xxxxx (0x XX XX)
EGD's PDU Field:
Offset
Bytes
Hex code
PDU Type:
0
1
0x 20
Message Flag:
1
1
0x HH
Request ID:
2
2
0x HH HH
PVN1:
4
1
0x 01
Option Length:
5
1
0x HH
Message Length:
6
2
0x HH HH
Configuration Signature:
8
2
0x HH HH
Address Type:
10
1
0x HH
Cell Count:
11
1
0x HH
Producer ID:
12
4
0x HH HH HH HH
Exchange ID:
16
4
0x HH HH HH HH
Time Stamp:
20
8
0x HH . . . HH
Reserved:
28
4
0x HH HH HH HH
The following two items are referred to as the exchange Cell. Each Cell
targets one [EGD Exchange] command line present in the EGD Module's
configuration file.
Offset: reads the DB Register specified in the Command.
Length: is Bytes count not Words.
Multiple Cells may be requested dependent on the Cell Count: field
specified above.
Offset:
32
2
0x HH HH
UDP
EGD:
Length:
34
2
0x HH HH