I’m writing a Component for the Visonic Powermax Burglar Alarm (here) and I have a problem that I’m hoping someone can help me with. When the connection between the Alarm Panel and HA is broken (TCP over Ethernet for example) I can trap it with an exception handler and re-connect to the Alarm Panel but I get exceptions like this:
2019-01-06 19:38:44 ERROR (MainThread) [homeassistant.core] Error doing job: Task exception was never retrieved
Traceback (most recent call last):
File “/usr/src/app/homeassistant/helpers/entity_platform.py”, line 344, in _async_add_entity
raise HomeAssistantError(msg)
homeassistant.exceptions.HomeAssistantError: Entity id already exists: sensor.visonic_z03. Platform visonic does not generate unique IDs
I know that the entities still exist from the previous execution before the re-connection to the Alarm Panel, so I tried removing the state using “hass.states.async_remove”. This didn’t make any difference.
Is there a method within HA to remove an already existing entity by entity_id? Not just the state but the entity itself.
Or is there are method so I can simply remove all entities for my Platform? i.e. Unload a Platform?
The alternative is that I test to see a sensor already exists before I call “discovery.load_platform”
Please keep in mind that I’m just learning the HA Architecture and so may have mixed up entity, component, platform and any other key words 
Any help would be much appreciated