Architecture choice: Modbus TCP has no network discovery mechanism, so
discovery piggybacks on nymea's NetworkDeviceDiscovery (ARP/mDNS scan)
and then probes each host via GET /RealTimeData (V2C Trydan HTTP REST API).
The presence of a "Paused" field in the JSON response is used as a Trydan
fingerprint — it matches the charger model and is absent on generic devices.
cf. evcc charger/trydan.go realTimeData struct.
Probes run concurrently (one QNetworkReply per host) but the sequence
terminates via two independent paths that could both fire:
1. The NetworkDeviceDiscoveryReply::finished callback arms a 3-second
QTimer::singleShot to give outstanding probes time to complete.
2. Each probe completion path checks (m_scanFinished && pendingProbes==0)
and calls finishDiscovery() early if all probes are already done.
A m_finished bool guard prevents double-emission of discoveryFinished()
if both paths fire in quick succession (e.g. all probes complete exactly
as the timer fires).
Manual-entry (createMethod "user") skips discovery entirely; setupThing()
is called directly with the user-supplied IP.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Architecture choice: separate the register map / business logic from the
physical transport. TrydanModbusMaster (abstract QObject) holds:
- the complete ReadRegister / WriteRegister enums with addresses
- float32 Big/Big decode helpers (memcpy pattern, matches pymodbus
BinaryPayloadDecoder byteorder=Endian.Big wordorder=Endian.Big)
- all last-polled cached values accessible via simple getters
TrydanModbusTcpMaster (concrete, Étape 1) wraps libnymea-modbus
ModbusTcpMaster. Each register read is a distinct FC3(addr, 2)
transaction via a recursive runReadSequence/doNextRead pattern —
never a block read, because the V2C firmware's register windows
overlap (0x0BC2 and 0x0BC3 each span 2 registers, so a range read
starting at 0x0BC2 for ≥3 registers returns garbage for the second
value). Writes use FC6 (single uint16, not float).
writeCompleted(quint16 address, bool success) carries the originating
register address so that concurrent background writes (e.g. PauseDynamic
from the conflict manager firing during an action) do not interfere with
action handlers waiting on a specific register's acknowledgement.
0x177E (Dynamic) is intentionally absent from WriteRegister: writing it
to 0 silences ChargePower telemetry even though the charger keeps running.
cf. evcc charger/trydan.go and github.com/evcc-io/evcc/issues/28047.
Étape 2 (RTU) will add TrydanModbusRtuMaster on the same interface;
no changes to plugin or register logic will be required.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
