ProSoft Technology MVI56-AFC - Manual (Page 115)

MVI56-AFC ♦ ControlLogix Platform Events
Liquid and Gas Flow Computer User Manual
ProSoft Technology, Inc. Page 115 of 316
February 25, 2011
9.2 Event Log Structures
The Event Log header contains housekeeping information for maintaining the
Log. Its layout is:
Address Description
40000 Number of records maximum ( == 1999 )
40001 Next new record position ( 0 thru maximum-1 )
40002 Next new event number ( 0 thru 65535, wrapping to 0 )
40003 Oldest event number on file
40004 Oldest event number on file not yet downloaded
40005-40007 [reserved]
Each event record is an 8-register quantity laid out as four 32-bit items (big-
endian):
Registers Contents
0 to 1 Event Id Tag (page 116)
2 to 3 Timestamp of event
In our standard "packed bit-field" format.
4 to 5 Old item value
For a Datum Point event, format depends on the "datum type" field of the
Event Id Tag.
6 to 7 New item value
For a Datum Point event, format depends on the "datum type" field of the
Event Id Tag.
Each value is right-justified in its field and sign-extended or padded with zeros (0)
if necessary, according to the source data type.