Rockwell Automation 1336T Function Block Prog. Manual, Series A/B - Manual (Page 120)

5–4 Block Transfer Services
1336 FORCE — 5.9 August 1995
The Event List Checksum message is a simple word addition of the
valid events in the current application. This does not include node
values or links.
PLC Block Transfer Instruction Data
BTW Instruction Length: 3 Words
BTR Instruction Length: 5 Words
0
Header
Word 1 Header
Word 1
3843
0
3843 –– Message OK
BRAM Event List Checksum
0
Message Structure
Header
Word 2
Data
Word 3
Header
Word 2
Header
Word 3
Data
Word 4
0
PLC Request –– Block Transfer Write
Drive Response –– Block Transfer Read
Execution Data
Word 5 Event List Checksum (RAM)
–28925 –– Message Error
Dec
Message Operation
The Event List Checksum message returns the sum of the valid events
in the active application (RAM) and in BRAM. The drive makes a
checksum value available so that you can differentiate between the
running application and the application stored in BRAM.
When you request an Event List Checksum, the drive returns the
BRAM event list checksum in word 4 and the execution list
checksum in word 5. If the checksum values are the same, then the
current application has the same events. However, there may be
differences in the links or node values or in the order of events.
Application Status
Services:
Event List Checksum