Battery Backups on a Building Automation System

A building automation system can lose some data or have issues recovering whenever they experience a brief power failure. It is impossible for us to control the weather or the reliability of the power grid. Taking certain steps can help to ensure data isn’t lost and that devices return to normal operation once reliable power is restored.

The supervisory device such as an NAE NCE or Jace is usually the most impacted device within a building automation system. If power is restored before the NAE has had time to completely shut down, they can lock up and require a power cycle to get them back online. I’ve seen systems not start properly or fail to start at all when a supervisory device fails to come back online.

Factors that influence device recovery

Many things can influence these devices ability to recover including the version of the operating system such as Metasys or Tridium it is running and the total number of devices connected. The amount of logic contained in the supervisory device can also influence the recovery.

Johnson Controls NAE’s and NCE’s usually have a small battery that is intended to aid in a proper shutdown in the event of a power failure. It has been my experience that these small batteries don’t always help overcome short power outages. A Tridium Jace will often use a capacitor that helps the device shut down normally.

Adding a UPS battery backup to a building automation system, particularly the main supervisory device, can help to reduce the issues that can happen in the supervisory device. It may not eliminate all of the issues but it will give your system the ability to ride out short power outages.

A battery backup is usually put in line with the main power feeding the device and while it cannot eliminate all of the problems you may face, it can significantly reduce some of the issues caused by a power blink.