Custom Historical Logging
eWON already embeds a powerful historical logging feature. So in most of the cases you should use this feature to store your historical data.
Using the embedded historical logging of the eWON also allows simple synchronization of the data with a centralized server using the DataMailbox or eSync for example.
However, for some projects, it may be required to store other types of data (strings for example) or to store the data in another format. In this case you may need to script the logging by your own. Using scripting you'll create files inside the /usr directory of the eWON and insert/append data into these files.
Discover more in the programming section.
Basic Script example:
Rem timer of 600 seconds --> 10 min TSET 1,600 ONTIMER 1, "Goto EVENT_TIMER" Rem close file in case it is still opened CLOSE 1 Rem Write file header OPEN "file:/usr/db.txt" FOR BINARY OUTPUT AS 1 PUT 1,"TimeStamp;Tagname;Value" + CHR$(13)+ CHR$(10) CLOSE 1 END EVENT_TIMER: OPEN "file:/usr/db.txt" FOR BINARY APPEND AS 1 PUT 1,TIME$ + ";" + "Tank1" + ";" + STR$ Tank1@ + ";" + CHR$(13)+ CHR$(10) CLOSE 1