Niagara - BACnet - Change Of Value - Configuration

The article outlines how to properly launch the ‘Change of Value’ subscription in the Niagara system. Initially, it is required to correctly configure the BACnet driver, which is not covered in this article.

In the first step, enable the ‘Change of Value’ subscription for the BACnet network. In the ‘Config->Drivers->BacnetNetwork->Tuning Policies’, change the ‘Use Cov’ slot value to true.

Figure 1. The ‘Change of Value’ configuration in the BACnet network

Next, go to the device, which points are served with the ‘Change of Value’ subscription, e.g. ‘Config->Drivers->BacnetNetwork->iSMA-B-MIX18-IP’. In the ‘AX Property Sheet’ view, change the ‘Use Cov’ slot value to true.

Figure 2. ‘Change of Value’ configuration in the BACnet device

With the above two steps completed, all device’s points, supporting the ‘Change of Value', will update their values in the BACnet network according to the ‘Change of Value’ subscription.

Figure 3. The ‘AX Property Sheet’ view of the UI-1 input with the ‘Change of Value’ subscription enabled