As to save precious SAP resources, it is good to automatically logged users out whose sessions have been idle after a period of time (for example, no activity after 30 minutes or 1 hour).
You can do that in transaction RZ10.
Use the Instance Profile and tick Extended maintenance
The Parameter is : rdisp/gui_auto_logout
If no entry is made for rdisp/gui_auto_logout (in seconds), the frontend is automatically logged off.
If the parameter has the value 0, no automatic logoff.
Save your entries and ensure that the profile is activated.
You need to re-start your SAP instance before the paramaters settings becomes active.
The paramaters applied to all the SAP users that have login to the system.
Currently, there are no parameters where you can exclude a list of SAP users that are subject to this auto logged out by the system.
For those who are using two R/3 instance, you can separate them into two groups, one with the automatic logged out and the other group that will not be subject to automatic logged out.
Source from :http://www.sap-img.com/basis/sapgui-logged-out-automatically-after-certain-time.htm
