Is there possibility to set Plone to log off authenticated user after 30 min idle time?
sure. see https://pypi.python.org/pypi/plone.session. Cookies will expire if you have done no actions and you set the expiration time.The only trick is that sometimes someone might edit a page for longer than 30min. See the ticket refresh section about a js solution to that.
Code of Conduct –
Hosting courtesy of Rackspace