Editing Knowledge Base:KNX

KNX Emergency Light Status
by Mick Martin | Feb 28, 2012 | Knowledge Base

The Objective

Our client wanted the Emergency lighting in a 6 floor office building to perform the regulation periodic tests and log the results of those test. The results had to be interpretted in to a verbose form to generate alarms and histories.

These were Dali fixtures connected on a KNX network. The status return values take the form of a 3 byte hexadecimal number.

Three test were to me performed primarily to test the health of the batteries.

Once a week the system performs a function test to get the fixtures general functions and retrieve the Battery heath
Once a month the system does a short duration test to check the capabilities of the battery
Once a Year the system does a long duration test to check the capabilities of the battery system.
Deployment

We used two Tridium Jace 250 controllers which were set up to talk KNX to the Dali lighting and BacNet to the Trend Supervisor system.

The core problem to solve was the interpretation of the 3 byte hex return status. We wrote a Niagara Java component to accomplish this task. This component sends a history statement to state what type of test was initiated on a particular fixture and the return status in a readable form. In the event of any failures or actual error messages these are send to an Alarms page so that engineers can quickly identify problems in teh emegency lighting.

The Jace controller exposed these histories and alarms via a web page which the engineers could display either on the Trend Supervisor or a mobile device.