Field help (EDSDAT) 

Code for the elementary or composite data.

The elementary data can be grouped as composite data.

To declare a composite data, the composite header code is entered here.

Elementary data is codes over 4 integers (e.g. : "0062").

Composite data is coded over 4 characters and starts with "C" or "S", followed by 3 integers (e.g. : "C516").