RMG TME400-VM VMF Series Operating Manual page 98

APPENDIX
Content of the header after the writing of the second archive entry:
Content
Position number of the next archive
Index of the oldest entry
Index of the newest entry
92
CRC16
Content header after the writing of the 300
Content
Position number of the next archive
Index of the oldest entry
Index of the newest entry
CRC16
Content header after the writing of the 301
(archive full, oldest entry overwritten in the ring buffer):
Content
Position number of the next archive
Index of the oldest entry
Index of the newest entry
CRC16
Procedure for determining the indexes to be read in the archive:
• Reading all four archive headers of an archive type
• Recognizing the current header
• Determine the range to be read:
If "Index oldest entry" = FFFFh and
"Index newest entry" = FFFFh, then the corresponding archive is empty
If "Index oldest entry" = 0 and "Index newest entry" = 0, then
the archive contains an entry
If "Index oldest entry" < "Index newest entry", then the
•
Number of entries = "Index newest entry" - "Index oldest entry" + 1
• If "Index oldest entry" > "Index newest entry", then the
No. of ent. = max. archive ent. - "Index older ent." + "Index newest ent." + 1
(Archive is always full: Number of entries = Maximum archive entries,
Calculation for the purpose of completeness only)
Manual TME400-VMF · EN07 · December, 7
Data type
UINT16
UINT16
UINT16
UINT16
th
archive entry (archive full):
Data type
UINT16
UINT16
UINT16
UINT16
st archive entry
Data type
UINT16
UINT16
UINT16
UINT16
th
2020
Value
2
0
1
xxxxh
Value
300
0
299
xxxxh
Value
301
1
0
xxxxh