I got a call last Tuesday late, when the techs onsite found both systems delivering gas and were both online. After further investigating why both systems were online, it was found that a brown out condition existed onsite. Due to the extraordinary services the gas cabinet controller recovered after the electrical event to keep supplying critically needed gas to the Fab thereby avoiding the expense of an unplanned shutdown. I found out the nature of this program is called an auto-recovery program to keep systems online during a electrically challenged event. To recover the systems back to normal operations you need to change states of the internal flags in the programming for the Gas Cabinet controllers to be cleared and readied for one system online and the other to be in standby. This one feature of the controller’s is not widely published but would enhance the “selling features” of the equipment.