In July of 2018, I wrote an article about The Importance of Probe in BACnet. As a quick recap, when you probe a BACnet Controller in CBAS, the resulting probe file allows points to be imported into the database easily with minimum manual data input. Probing also automatically sets some of the BACnet services that the controller supports, like Read Property Multiple and COV (Change of Value). These are two services that can make BACnet communications more efficient.
When setting up 485 communication to a BACnet device like an AHU, it is important that you Probe it. This gets you some important information:
Instance number is a good thing because if you add it to the program screen of the controller, it connects much faster when CBAS is restarted. Instance is usually provided in the Probe file but can sometimes have a different name.
A Probe gets you the list of points that are on the AHU controller. Then you can add them from the Probe file easily by clicking the controller then click Add Points From Probe File.
Perhaps the most important advantage to probing is that it automatically sets a few parameters to be used by CBAS that can improve performance. Note that you can alternatively set these parameters manually.if probing isn’t possible The most useful of these settings are are COV and Read Multiple. COV is Change of Value and if it is available, it sends any changes in value to the host. Read Multiple reads up to 14 points at a time. By default, CBAS only reads one point at a time unless you have Read Multiple set.
As a part of our services, Computrols offers 24/7 phone support to all of our customers. If you have ever taken advantage of this offering, you have likely spoken to our Technical Support Manager, George Hingle. George has been employed by Computrols for over 15 years and is one of our most knowledgeable team members when it comes to troubleshooting in CBAS. As a means building on our already robust FAQ page, George has agreed to share some common challenges he sees in our newsletter each month. Continue reading George’s CBAS Tips, March 2018→
Computrols is now a Silver Member of BACnet International, an industry association that facilitates the successful use of the BACnet protocol in building automation and control systems through interoperability testing, educational programs and promotional activities. We are eager to continue testing our products through BACnet Testing Labs (BTL) and gaining more exposure through our membership. Continue reading Computrols Joins BACnet International→