Once a temperature sample has been taken and stored in the onboard FRAM of the TV2 ThermaViewer it can not be changed.
The time and temperature display parameters can be changed if the user has the proper password, but the underlying data can not be altered. It is stored in FRAM so even if power is lost the data is protected. You can literally turn the TV2 off, run the battery all the way down, walk away and come back 2 years later and your data will still be there.
When the collected data is downloaded to a computer the TView program displays it as a chart. Charts from multiple TV2s can be combined. Data from one sensor can be moved to the chart of another sensor or deleted from a chart or data from all sensors from one or more sensors can be seen on one chart. Charts can also be printed out.
Additionally the charts can be exported to an XLS file which can be viewed with Excel. If the data is saved rather then exported it is saved as an encrypted file with a TXV file extension, which can only be read or printed with the TView program. If a previously saved 'txv' file is loaded into the TView program a small icon appears on the screen indicating that you are viewing encrypted data.
If exported data is loaded into Excel, Word, Notepad or some other text editor type program it can be manipulated and re-saved but can not be loaded into the TView program. In other words it can be changed. Once this happens it no longer meets the requirements of US regulation 21 CFR part 11. As long is the data is in an TXV file it is encryped and complys with the 21 CFR 11 requirements.
Temperature history chart downloaded to a computer.