Events and Throttling

Events and Throttling

Inverter events

Modbus reports events only as severity bits (Event severity), and none that only the service level sees. The inverter's web interface lists every event with its code, its time and a text; the integration reads that list without a login, so an entry without the web API has it too.

The inverter keeps events of three levels: the customer's, the technician's and the service's. Its web interface shows a customer login the customer level alone, and so do these entities, whatever login the entry uses. An event of the other levels can stay active for weeks without a visible effect, such as a failed arc-fault self test or an unreachable network gateway. The service entities show them; they start disabled.

Entity	Type	What it shows
Active event	sensor, diagnostic	The text of the leading active customer event: an error before a warning before an info, the newest among equals. OK while none is active; unknown while the list could not be read.
Active events	sensor, diagnostic	How many customer events are active.
Inverter event	event	Fires once for every new customer entry of the inverter's event log, with the severity as its event type. It catches entries that last no time at all and never show as active, such as a short battery fault. Unavailable while the log does not answer.
Active service event Active service events Service event	sensor, sensor, event; disabled by default	The same for the technician and service levels, which the web interface hides from a customer login, and for an event of a level in no known form (visible_to null).

Attributes

Active event and the events carry:

Attribute	Content
code	The event code, such as GEN24-1175.
text	The inverter's text for it.
severity	error, warning or info; null for a severity in no known form.
visible_to	The level: customer, technician or service; null for a level in no known form.
since	When the event started, by the inverter's clock.
confirmable	Whether the event waits to be confirmed.

Active event adds the other active events under other_events. The event type of Inverter event and Service event is the severity: error, warning, info, or unclassified for a severity in no known form.

Timing and texts

• The texts come from the inverter itself, in Home Assistant's language, and in English where the inverter has none in that language; a code without a text shows its short name. They are read once: after changing Home Assistant's language, reload the entry.
• The active events are read with every web poll; the log (about 60 KB) at the first web poll after 5 minutes have passed, and again at the next poll when it did not answer. An entry therefore arrives up to 5 minutes plus one web interval late (longer while the web API fails), with its own time in since.
• The log is read once at start without firing: entries from before, and from while Home Assistant was off, do not fire. When the web API fails before that first read, the first read that succeeds fires the entries that started after the failure, by the inverter's clock.
• severity and visible_to are read from the inverter's log; Fronius does not document them. On the inverters seen, the nightly "not enough DC power" is a warning a customer sees, the daily isolation measurement an info of the technician level.
• The integration does not confirm events. The few that need it (such as too many shutdowns in backup mode) are meant to bring someone to the system; confirm them in the inverter's web interface.
• Firmware without the event endpoints leaves Active event, Active events and their service counterparts unknown, and Inverter event and Service event unavailable.

An automation that notifies on errors and warnings is in Examples.

Throttle reason

The Throttle reason sensor names the limit the output is held at right now. A limit that is only switched on, such as an AC limit at 100 % or above the current output, is no reason.

State	English	German	When
none	Not throttled	Keine Drosselung	No limit holds the output.
ac_limit	AC limit	AC-Leistungsbegrenzung	A percentage limit is reached, such as the AC limit (AC limit enable, AC limit rate).
feed_in_limit	Export limit	Einspeisebegrenzung	A limit in watts is reached. Measured with the export limit set in the inverter's web interface; other limits in watts may report the same way.
inverter_state	Inverter reports throttling	Wechselrichter meldet Drosselung	The inverter reports the SunSpec operating state throttled (model 101/103 St).
several	Several reasons	Mehrere Gründe	More than one of the above at once.
active_power_control	Active power control	Wirkleistungsvorgabe	No longer reported; kept so older history keeps its label.
export_limit	AC limit	AC-Leistungsbegrenzung	No longer reported: up to 1.2.0b4 it meant an AC limit that was switched on. Kept so older history keeps its label.
unknown			No reason is found while a source is missing: the component endpoint or model 101/103 could not be read, the last web poll failed, the firmware does not report the flags, or the entry waits for a new web login. A reason one source names is shown even while the other is missing.

Where the states come from, measured on a GEN24 and a Verto:

• ac_limit and feed_in_limit come from the inverter's component endpoint (/api/components/inverter/readable): ACBRIDGE_VALUE_POWERACTIVE_RELATIVE_PRODUCTION_LIMIT_REACHED_U8 is set while a percentage limit holds the output, ACBRIDGE_VALUE_POWERACTIVE_PRODUCTION_LIMIT_REACHED_U8 while a limit in watts does. They need no login, so an entry without the web API has them too.
• The Modbus signals only say a limit is switched on: StActCtl bit 0 (model 122) is set as soon as the AC limit is enabled, even at 100 %, and a GEN24 left St at normal while it throttled. They are not used for the reason.
• The flags come with the web poll, which updates the sensor on its own, so the reason can trail a change by up to the web interval (default 60 s). While Modbus is down the sensor stays available as long as the web poll answers.

The component sensors Output power limit and Output limited show the limit in effect and whether a limit set on the inverter holds the output; Surplus power available (disabled by default) was seen on two inverters to be yes while an export limit curtailed PV, no otherwise, also while the AC limit held the output. Fronius does not document it.