oAlarmItem.Extension()If an error occures, then the method returns: null for JavaScript or Nothing pro VBScript (it can be tested by the Pm.IsValid method). It means that the alarm did not originate in the data extension..
var nMin1;
var oItem = pMe.Pm("/AlarmsGroup").Item("analog1");
var oExt = oItem.Extension();
if (oExt)
nMin1 = oExt.Min1;