Timeout of Sessions can be influenced on a system- an application- and user-base. Here are the relevant Parameters:
First of all there is SYSPARMS TODISC. That parameter can be changed via /PARMS in Parameter Group $NM TIMEOUT. The values of these parameters can be displayed in OCS using command SHOW SYSPARMS=TO.
In the DEFLOGON statement for an application you can specify MTACTION=... and MTLIMIT=...
MTLIMIT specifies an inactivity time-out limit that applies to MAI sessions established using this DEFLOGON entry
MTACTION specifies the action to take when an MAI session is inactive for the time specified by MTLIMIT. Details can be seen when you enter DEFLOGON in OCS and hit PF1 to get the complete help for that command.
The SYSPARMS TOTIME1, TOTIME2, TOACT1 and TOACT2 can be overriden in the second panel of UAMS for a user or a Group of users in section "Timeout Controls". Detailed informations on these parameters are available in the Online help (Press PF1 in the second UAMS panel and page forward to the last pages.