The default timeout value for the vCAC web console is 30 minutes. You might find this not long enough or too long, whatever your reasons are, if you want to change it you can.
Access the vCAC Appliance through SSH (with Putty for example) or access the virtual appliance console directly to modify this file:
for 6.0 /usr/lib/vcac/server/webapps/shell-ui-app/WEB-INF/web.xml
for 6.2 /usr/lib/vcac/server/webapps/vcac/WEB-INF/web.xml
Use vi or another editor to modify the default 30 minutes in another value or use -1 to disable the timeout completely. (instructions to use vi)
<!-- 30 minutes session expiration time -->
<session-config>
<session-timeout>30</session-timeout>
<tracking-mode>COOKIE</tracking-mode>
</session-config>
After this modification restart the vCAC service:
/etc/init.d/service/vcac-server restart
Or restart the entire appliance.