Issue
When configuring BACnet alarms in EcoStruxure Building Operation (EBO), users may encounter a potentially misleading message in the Monitored Variable description:
Monitored variable: Choose the method for referencing the property that you want to monitor. Select System reference to define a path-based reference to an object or property that is currently located on the EcoStruxure BMS server.
While technically correct, this statement may cause confusion. It suggests that any object or property on the EBO server can be used as a monitored variable for BACnet alarms. However, only specific BACnet objects and properties are supported for each alarm type.
Product Line
EcoStruxure Building Operation
Environment
- EcoStruxture Building Workstation
- Bacnet
- Alarms
Cause
The ambiguity arises from the assumption that all BACnet objects and properties are valid for alarm monitoring. In reality, only a subset is supported depending on the alarm type. Misconfiguration can lead to unexpected behavior or non-functional alarms.
Resolution
To ensure proper configuration, refer to the table below for supported combinations of BACnet objects and properties for each alarm type:
| Alarm Type | Monitored Variable Object | Monitored Variable Property |
|---|---|---|
| Change of State | BACnet Digital Input | Value |
| BACnet Digital Output | Value | |
| BACnet Digital Value | Value | |
| BACnet Multistate Input | Value | |
| BACnet Multistate Output | Value | |
| BACnet Multistate Value | Value | |
| Change of Value | BACnet Analog Input | Value |
| BACnet Analog Output | Value | |
| BACnet Analog Value | Value | |
| Floating Limit | BACnet Analog Input | Value |
| BACnet Analog Output | Value | |
| BACnet Analog Value | Value | |
| Floating Limit Setpoint Reference | BACnet Analog Input | Value |
| BACnet Analog Output | Value | |
| BACnet Analog Value | Value | |
| BACnet Loop | Setpoint | |
| Out of Range | BACnet Analog Input | Value |
| BACnet Analog Output | Value | |
| BACnet Analog Value | Value | |
| BACnet Digital Input | Value | |
| BACnet Digital Output | Value | |
| BACnet Digital Value | Value | |
| BACnet Multistate Input | Value | |
| BACnet Multistate Output | Value | |
| BACnet Multistate Value | Value | |
| Buffer Ready | BACnet Trend Log (Any) | — |
Additional Reference
For more details, see:
🔗 BACnet Alarm Types and Monitored Variables Table
