Long Energy

Long Energy is sent by the devices to the server upon request. Long Energy entries are stored on the devices on persistent storage in 5min (300 secs) granularity. Long energy delivery is guaranteed - if the device records the data, it will be sent to the server reliably, possibly after a delay.

Short Energy

Short Energy instead is sent by the devices automatically every 5 to 295 seconds (depending on configuration; the default is 30 secs) with no guarantee of delivery. Short Energy entries are not currently stored on the devices and thus can be lost if the device loses connectivity with the server or simply if UDP data is lost during transmission (UDP has no guarantee of delivery).

What measurements do Wattwatchers devices report?

And what do they mean?

AttributeIncluded inFormatUnitsDescription
eRealShort Energy, Long EnergyIntegerJoules (J)Real Energy.
eRealPositiveLong EnergyIntegerJoules (J)Positive Real Energy. Over the Long Energy period there may be points of negative energy (e.g. drawing energy from the grid) that are "hidden" in the eReal value for the period if the overall total is negative (for example if solar generation results in an overall export for the period). eRealPositive enables you to determine the total positive flows during the period.
eRealNegativeLong EnergyIntegerJoules (J)Negative Real Energy. Over the Long Energy period there may be points of negative energy (e.g. exports to the grid) that are "hidden" in the eReal value for the period if the overall total is positive. eRealNegative enables you to determine the total negative flows during the period.
eReactiveShort Energy, Long EnergyIntegerJoules (J)Reactive Energy.
eReactivePositiveLong EnergyIntegerJoules (J)Positive Reactive Energy.
eReactiveNegativeLong EnergyIntegerJoules (J)Negative Reactive Energy.
vRMSShort EnergyFloatVolts (V)Volts Root Mean Square (RMS).
vRMSMinLong EnergyFloatVolts (V)Minimum Volts RMS. As voltage is an instantaneous value, only the minimum and maximum that occurred within the period are reported for Long Energy.
vRMSMaxLong EnergyFloatVolts (V)Maximum Volts RMS. As voltage is an instantaneous value, only the minimum and maximum that occurred within the period are reported for Long Energy.
iRMSShort EnergyFloatVolts (V)Current Root Mean Square (RMS).
iRMSMinLong EnergyFloatVolts (V)Minimum Current RMS. As current is an instantaneous value, only the minimum and maximum that occurred within the period are reported for Long Energy.
iRMSMaxLong EnergyFloatVolts (V)Maximum Current RMS. As current is an instantaneous value, only the minimum and maximum that occurred within the period are reported for Long Energy.
frequencyShort EnergyFloatHertz (Hz)Voltage Frequency. Measured off P1.

Single, two and three phase power

See the Background/Concepts section of the phase grouping support note for more information.

Converting energy units

The API provides energy values in Joules, which can then be converted into different units.

"Catch-up" mode

There are circumstances where a device may continue to collect data but be unable to transmit that data to the Wattwatchers system for a period. When the device re-establishes communications with our cloud infrastructure it will progressively send the data it has collected (i.e. it doesn't do this all at once).

When a device is in this mode, data will appear delayed in being available in other parts of the system, e.g. via the API.

Learn more: