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At transmission time
Files are first checked for expiry:
The timestamp of the file is compared to the transmission time. If the difference in time is
greater than the File Expiry Period setting, the file is considered expired.
All expired files are deleted.
Any remaining files in the transmission folder are transmitted
The newest file is transmitted first.
The number of transmitted files may be limited using the Max Files Per Tx setting.
If Max Files Per Tx is set to 1, only one file will ever be transmitted at each transmission time.
If a file transmission should fail, that file will never be transmitted.
Otherwise, files that were not transmitted on time may be transmitted in subsequent
transmissions.
If there are no files in the folder, the transmission will fail with an error.
Transmitted files are deleted:
Once a file is successfully delivered to the FTP server, the file is deleted from the transmission
folder.
In order to both transmit a file and keep the file on the SD card, have the Python script save two copies of
the file. One copy should go into the transmission folder, the other into any other folder.
Please note file deletions:
Successfully transmitted files are deleted!
Old, expired files are deleted!
Example Scenarios
The scenarios below illustrate how to use the Max Files Per Tx and File Expiry Period settings.
The system creates and transmits one file every two minutes. Only the most recent file is relevant.
Set Max Files Per Tx to 1. This ensures only the most recent file is transmitted.
Set File Expiry Period to 4 minutes. The ensures unwanted files do not accumulate on the SD
card.
The system transmits one file every 4 hours. All files are important.
Leave Max Files Per Tx at the default 16. This ensures that, if a transmission fails, subsequent
transmission transmit older files.
Leave File Expiry Period at the default of 7 days. This ensures that files are kept until transmitted
while at the same time ensuring that a station does not transmit old files after a prolonged
shutdown.
Summary of Contents for SUTRON XLINK 100
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