OFF-LINE logging - be sure the device internal clock is correct
Data logging takes place on a routine basis and the log file is saved on:
- an external USB memory disk or
- an external PC connected via LAN cable
Logging starts whenever an USB-memory stick formatted FAT 32 and larger than 256 MB is inserted into the USB socket of the specific device. The logging visualization shows the instructions seen below in green on the device monitor.
Every hour one comma-separated CSV file is created and saved on the USB-memory stick. Every hour the previous CSV file is upgraded and as such the new CSV files overwrites the previous CSV file.
Two CRON Linux scripts are running:
- Short term storage - one first script copies the CSV logfile from internal RAM disk to external USB-memory once per hour
- Long term storage – a second rotating script compresses the files stored in RAM and save the file to the USB-memory every week and hereafter starts a new week log file
In case of power failure or if the USB-memory is removed in an irregular way- loss of data is reduced to max 1 hour.
The logging is done by the “Composer” program from www.Codesys.com according to the IEC 61131-3 standard.
When STOP is pressed and all data is safely stored on USB-memory the EJECT bottom becomes active. The out greyed eject button indicates it has been pressed once, and the USB-memory can be removed and data stored like on a PC.
Dated: 2025-07-01
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