Key concepts
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?
| Attribute | Included in | Format | Units | Description |
|---|---|---|---|---|
eReal |
Short Energy, Long Energy | Integer | Joules (J) | Real Energy. |
eRealPositive |
Long Energy | Integer | Joules (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. |
eRealNegative |
Long Energy | Integer | Joules (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. |
eReactive |
Short Energy, Long Energy | Integer | Joules (J) | Reactive Energy. |
eReactivePositive |
Long Energy | Integer | Joules (J) | Positive Reactive Energy. |
eReactiveNegative |
Long Energy | Integer | Joules (J) | Negative Reactive Energy. |
vRMS |
Short Energy | Float | Volts (V) | Volts Root Mean Square (RMS). |
vRMSMin |
Long Energy | Float | Volts (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. |
vRMSMax |
Long Energy | Float | Volts (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. |
iRMS |
Short Energy | Float | Volts (V) | Current Root Mean Square (RMS). |
iRMSMin |
Long Energy | Float | Volts (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. |
iRMSMax |
Long Energy | Float | Volts (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. |
frequency |
Short Energy | Float | Hertz (Hz) | Voltage Frequency. Measured off P1. |
eRealKwh |
Short Energy, Long Energy | Float | Kilowatt Hours (kWh) | Real Energy converted from Joules to kilowatt hours. |
eRealPositiveKwh |
Long Energy | Float | Kilowatt Hours (kWh) | Positive Real Energy converted from Joules to kilowatt hours. |
eRealNegativeKwh |
Long Energy | Float | Kilowatt Hours (kWh) | Negative Real Energy converted from Joules to kilowatt hours. |
eReactiveKwh |
Short Energy, Long Energy | Float | Kilowatt Hours (kWh) | Reactive Energy converted from Joules to kilowatt hours. |
eReactivePositiveKwh |
Long Energy | Float | Kilowatt Hours (kWh) | Positive Reactive Energy converted from Joules to kilowatt hours. |
eReactiveNegativeKwh |
Long Energy | Float | Kilowatt Hours (kWh) | Negative Reactive Energy converted from Joules to kilowatt hours. |
pRealKw |
Short Energy, Long Energy | Float | Kilowatts (kW) | Real Energy converted from Joules to kilowatts. Note this is a conversion of energy to power, thus the prefix changes to p. |
pRealPositiveKw |
Long Energy | Float | Kilowatts (kW) | Positive Real Energy converted from Joules to kilowatts. Note this is a conversion of energy to power, thus the prefix changes to p. |
pRealNegativeKw |
Long Energy | Float | Kilowatts (kW) | Negative Real Energy converted from Joules to kilowatts. Note this is a conversion of energy to power, thus the prefix changes to p. |
pReactiveKw |
Short Energy, Long Energy | Float | Kilowatts (kW) | Reactive Energy converted from Joules to kilowatts. Note this is a conversion of energy to power, thus the prefix changes to p. |
pReactivePositiveKw |
Long Energy | Float | Kilowatts (kW) | Positive Reactive Energy converted from Joules to kilowatts. Note this is a conversion of energy to power, thus the prefix changes to p. |
pReactiveNegativeKw |
Long Energy | Float | Kilowatts (kW) | Negative Reactive Energy converted from Joules to kilowatts. Note this is a conversion of energy to power, thus the prefix changes to p. |
powerFactor |
Short Energy, Long Energy | Float | Power Factor | The calculated power factor for the channel. See [units-conversion.md#calculate-power-factor] for more information. |
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.