When you edit a session lifetime, you can change settings such as the maximum session lifetime, and the amount of time a session can be idle before the system closes it.
Before you begin
You must be a Super Admin.
In the Security Console, click Setup> System Settings.
Under Console & Session Settings, click Session Lifetime.
Click the session type that you want to edit, and select Edit, from the context menu.
Under Session Lifetime Settings, do the following:
Select Time out idle sessions, and enter the time-out duration, if you want to time out sessions after a period of inactivity.
Select Limit session lifetime, and enter the maximum lifetime of a session.
Session Lifetime Limits
Types of Session Lifetime Limits