Unexpected Counts: Saving the Raw Count Data
The raw count data can provide useful clues about problems to do with unexpected counts or folders found in the data directories and their files.
You can collect the raw counts from all the VT Loggers attached to the selected site. The counts from all epochs for all channels will be stored in an ASCII text file. (You wouldn't normally use this method to download data, but it is sometimes useful when setting-up the system.)
The Logger counts up continuously and rolls over to 0 when the count exceeds 65535. Epoch data is saved by subtracting the count value from the previous epoch to give the count in the current epoch.
Getting the raw count data
- Go to the Counts tab
- Click the Log all data epochs to file button
- The data will be uploaded from the logger to the file shown in the box beside the button.
Things to look for in the raw data file
-
Continuous good data
The first record in the raw counts file will be the most recently recorded epoch.
Your data epochs should then be at one epoch length apart as you go down the file.
There may be times when additional epochs are recorded, when the internal clock has been reset from the PC (done every time after a data upload with VTcollect). -
Times when the logger was reset
If the logger settings are disrupted, possibly by an electrical transient or by the internal battery going flat, the time in the logger reverts to 1/1/1970 and resumes from there until a new clock value is sent from the PC.
In between sections of good data values (see above) you may get sections where the date reverts to 1970, and these indicate when the LVT was reset. -
Times when the logger was powered down
The logger will not record epochs when the power is off, but the internal battery will hold the correct date-time for several days, so the unit will normally resume logging epochs when the power is restored. -
Every other Epoch is 0
The VT Collect software's number of epochs per day is different to the VT hardware. - If you can't fix the problem you can send the data file to us for advice about your problem.
Next: Unstable Zone Markers.