After adding a connection or binding a WattNode® network variable (SNVT), some or all of the WattNode variables may report zero for several seconds. The demand (nvoDemand) may report zero until the end of the next demand period, which may be 15 minutes, 30 minutes, or longer.
This happens if the LonWorks® network management tool (LNS®, LonMaker®, etc.) is configured to take devices–such as the WattNode–offline before making changes. This is the default for LonMaker.
There currently is no fix for this other than to perform all network configuration before starting to monitor the WattNode. Even if further network configuration is required, the brief periods where the WattNode is offline should have a minimal impact on the measured energy.