$sts = Get-SPSecurityTokenServiceConfig
$sts.FormsTokenLifeTime = (New-TimeSpan -minutes 30)
$sts.Update()
Get-SPSecurityTokenServiceConfig
$sts = Get-SPSecurityTokenServiceConfig
$sts.FormsTokenLifeTime = (New-TimeSpan -minutes 30)
$sts.Update()
Get-SPSecurityTokenServiceConfig