### Stability data upload (Excel)

#### Option 1

Stability data can be uploaded from an Excel file containing a single table
including columns `analyte`, `Date`, `Value` and `unit`. An additional column 
`Temp` can be included to allow shelf life calculations based on the Arrhenius 
model.

![**Info** Excel import format including temperature information for arrhenius calculations](fig/S_Modul_Import_Arrhenius.png)

The `Temp` column obviously should contain temperature levels in °C at which 
samples were stored before measurement. The lowest temperature level will be 
used as a reference point $T_\mathit{ctrl}$. This is also reflected in the 
specified `Date` values, where $T_\mathit{ctrl}$ will be treated as a reference 
time point. All other temperature levels should have *later* dates specified. 
For every measurement, the difference between its date and the reference time 
point will be computed to represent the storage time at this temperature.

Using dates instead of specifying storage time directly allows to compute 
stability and potential shelf life in both, relative (month) and absolute (date)
values.

#### Option 2

***Note!***
This option (simple Excel layout) might be discarded in the future. If you are
new to *eCerto* please use *Option 1*.

Prepare data in a single Excel file, using separate tables for each analyte 
as shown in the below example.

![**Info** Simple Excel import format for stability data](fig/S_Modul_Import.png)

Table names will be used as analyte names and should match analyte names from 
the Certification module. Column names need to be exactly `Value` and `Date` 
with Excel column formats set to *numeric* and *date* respectively.

#### Option 3

Upload can be also achieved from a previously created backup file. If a backup 
file does not contain any stability data, the Excel upload option will remain 
active (and will become deactivated if stability data are contained).
