How exactly does HA process trigger in a calendar? For instance it it triggers the heating on at 8am and off at 9am in my case a command is issued over wifi to a relay that turns the boiler on. It carries on on heating till the target temperture is reached.
What though happens if there is slight glitch so the command is not used by HA or there is wifi inteference that causes the relay not to receive the signal? Is there any follow up command say one minute later to repeat the trigger? Because, if not, I can see some on or off commands being missed?
In my old heating controller there was a check made every minute between 8 and 9 against the target temperture and so, if the inital command was missed, it would be picked up later.
Thinking about it, I am running a HA generic thermostat that resides in the HA software. All the trigger is doing is changing the target temperture that the software runs at. That trigger ought to be quite reliable unless the HA is running so many precesses at once that it stalls. No in may case as im not demanding much out of it.
If wifi/ bluetooth/ zigbee is flaky so either the temperture sensor flakily transmits temperture, or the relay flakily receives its command, it should not matter much becuse the thermostat sofware is presumably in a permanent short loop that is resending the relay command every time measured temperture is less than the target. So the relay gets recommanded every say one minute.
That is unless the software says IF I have sent a relay ON command THEN no need to resend until the command changes to an OFF. Does it?
You could measure the power used by the heater. There should be a notable difference between on and off. I use this approach to check if the valves for my irrigation have been switched on.
It’s what we call “fire and forget”. As mentioned, there’s no retry mechanism.
I only know about this one and haven’t used it myself.
I have one flaky light due to a reception issue, and there I just use a wait for template to ensure it’s in the desired state. Generally speaking, if you have a good network and solid devices, this kind of thing should be rare, but for critical functionality you might want to be sure.
My Shelly relay has a power meter in it so I guess I could use that to check it has triggered. But it would also have to include a statement to check that the target temperture is greater than the actual, because, if not, then the relay would be off anyway despite the calender triggering a heating session.