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14 LOG FILE DATA
The DAS stores data from the modbus devices in text (.CSV) log files. One log file is created for each
modbus device on the system. On a daily basis, the log files are “rotated”, that is, the current log file is
renamed and compressed with gzip compression, and a new log file is started. This allows the DAS to
make efficient use of the flash memory. When the storage capacity is beyond 95% full, the oldest log file will
be removed from the system.
14.1 Log File Status
The DAS can display a list of log files in the “log file data/status” web configuration page. A bar graph will
show the amount of storage capacity that is used by the existing log data. Below, a list of modbus device
log file will be displayed along with the file size and timestamp when the file was last modified.
Each modbus device may have multiple log files. The log file name starts with “mb-xxx.” where xxx is the
modbus device id number. One file, with the .log extension is the file where the most recent data is being
stored. Other log files have a .gz extension. These are older log data files that have been compressed to
save space.
The file name will be a link that will open up a browser window to view the contents of the single log file.
Clicking on the single log file will only show the contents of that log file, and not all historical data for the
device. Use the log export feature if all log data is required.
14.2 Log File Format
Once you have downloaded the data from the DAS , you will need to process it. The file is an ASCII text
file with comma delimited data. One line is recorded for each log cycle. The file will look something like the
following example from a 4A4P-M I/O Module.
‘2019-01-31 18:30:00’,0,0,0,-0.00,89.29,39.05,49.11,0,0,0,0
‘2019-01-31 18:35:00’,0,0,0x02,-0.01,104.24,39.05,49.11,0,0,0,0
‘2019-01-31 18:40:00’,0,0,0,,87.82,39.05,49.11,0,0,0,0
‘2019 01-31 18:45:00’,139,,,,,,,,,,
In this example, the first line shows a regular log entry. The second line shows a high range alarm for data
point 2. The third column shows point 1 as invalid, and the fourth line shows the Modbus device is
not responding.
Notice the following columns are shown.
1.
Date/Time in UTC (GMT) time. This field is quoted to handle the space in the middle.
The format is YYYY-MM-DD HH-MM-SS
2. Modbus error (if any). 0=no error, see table be low.
3. Low Range alarm bitmap (hex notation).
4. High Range alarm bitmap (hex notation)
5. Data point 1
6. Data point 2
7. - - -
8. Data point N
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