Password Protecting the TV2 Data.
The TV2 normally sits out where everyone can see it and examine the data. This is a good thing. The more people who are aware of the environmental conditions the quick any problems will be identified and the more conscious every one is of the importance of controlling the environmental conditions. The display allows anyone with interest in the data to zoom in/out of the data, enter a trace mode, or scroll back to data collected at some previous time. This is desirable, since it makes each person a part of the effort to monitor and control temperature.
While you want everyone aware of the data you do not want any one not authorized changing the TV2 parameters. The TV2 has a password system which prevents any unauthorized personnel from entering the menu system and changing the operational parameters. As long as the password system is active, anyone can push any button or look at any data value, but only those with the correct password can change parameters or settings.
Even with access to the menu system, the data itself is secure because it can't be changed, deleted or added to (although it can be erased). The logged data is completely protected and unchangeable.