Mitsubishi Electric MELSEC-Q series User Manual page 68

1.
Check the number of valid logging data with CH Number of logging data (Un\G1106 to Un\G1113).
When data is collected 5000 times or less
1st data
2nd data
3rd data
4th data
5th data
6th data
4999th data
5000th data
2.
Check where the latest data and the oldest data are stored.
The places can be checked in the following buffer memory areas.
• CH Head pointer (Un\G1090 to Un\G1097) (
• CH Latest pointer (Un\G1098 to Un\G1105) (
When data was collected 5001 times or more
Ex.
66
Valid data
CH Logging data = 5
Invalid data
(Data stored in this area is not reliable.)
CH Latest pointer : 5
CH Head pointer : 6
When data is collected 5001 times or more
1st data
2nd data
Valid data
3rd data
4th data
5th data CH
6th data
4999th data
5000th data
Page 131, Section 6.2 (43))
Page 132, Section 6.2 (44))
1st data
2nd data
3rd data
4th data
Latest data
5th data
6th data Oldest data
4999th data
5000th data
Logging data = 5000