A GEN24 answers for the inverter on one unit ID and for the Smart Meter
on another, behind the same host and port. Isolate the decision to open
that second connection as a pure function, so it can be pinned down
without nymea, and leave the logging of the refusal to the caller.
Refuses a meter slave ID out of the 0..247 range, treats 0 as "no meter
on this connection" as documented, and refuses a meter slave ID equal to
the inverter one: a second socket on the same unit ID would rediscover
the very same models and duplicate every child thing. That last case is
reachable, since the discovery writes the scanned slave ID into the
thing parameter.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Adds a fronius vendor and a froniusConnection thing class alongside the
generic sunspec and solarEdge ones, following the SolarEdge mechanism but
none of its workarounds - no proprietary battery block and no PV
production computed by difference, since the GEN24 exposes model 160.
FroniusRules holds the vendor decisions as pure functions:
- discovery only keeps devices announcing Fronius as manufacturer;
- the byte order is the SunSpec default, not the forced big endian that
is specific to SolarEdge, and no endianness parameter is exposed;
- meterSlaveId defaults to 200, 0 meaning no meter on this connection;
- a hard 7 s floor on the poll interval. Polling faster can push the
inverter offline towards the vendor portal, and recovery needs an
AC+DC power cycle on site, so this is a guard in the code rather than
a configurable default;
- the registers the inverter accepts and then silently ignores are
refused before anything reaches the wire;
- the six HEMS battery modes map onto ChaGriSet, StorCtl_Mod, InWRte and
OutWRte, negative meaning charge;
- model 160 blocks are classified by IDStr, never by index: on a three
or four MPPT inverter the battery blocks are not in position 3 and 4.
Storages under a Fronius connection default revertTime to 300 s.
Setpoints now reread the scale factor before writing and read the written
registers back afterwards, reporting a mismatch through a new
controlHealthy state - the only defence against writes that are accepted
and then ignored without a Modbus exception.
Byte order and the revert timer semantics on model 124 are inferences, not
measurements; see specs/fronius-sunspec.md, H-2 and H-3.
