G3 sensor fault conditions not working

Issue

The sensor in the BACnet controller is open or shorted and the value at the ENC shows "nan" but no fault is annunciated?

Product Line

TAC I/A Series

Environment

I/A Series G3 (Niagara)

Cause

If the analog object in question is being polled, by default only the "present value" is retrieved and therefore the "nan" is displayed but the status remains as ok.  A polled point can be made to retrieve the "statusFlag" data also by altering its "facets" as shown in the Resolution. 

Resolution

It is normal for the MNB controller analog input present value to change to "nan" when the sensor is shorted or open. 

To annunciate a fault at the ENC:

Add the "OutOfRangeAlarmExt" to the analog input object and program it to have the "fault" conditions annunciated. 

If this object is defined to use COV notification the "present value" and "status flags" are reported by default.  Therefore,  the "nan" value is displayed and handled as a fault condition and annunciated. 

However, if the analog object is being polled, by default only the "present value" is retrieved and therefore the "nan" is displayed but the status remains as ok.  A polled point can be made to retrieve the "statusFlag" data by altering its "facets".  With the object properties displayed on the Facets property click on >> and add a key as shown below.