Is there a way to trap a Null return from a Temperature Sensor?

[UKMedia]

I have a temp sensor that occasionally returns a 'Null' value. Is there a way of trapping this within Rule Machine?

Things I've tried:
Create a Virtual Temp sensor (Called Null Temp Sensor) and not set a reading, hoping that would be a Null value but it must create a default temp when created. The goal was to then check if the temp returned from the actual sensor was the same as my Null Temp Sensor device - that didn't work.

[jlv]

This sounds like an XY problem. What are you really trying to accomplish?

[UKMedia]

Hi and thanks for your reply.

Here is the rule for my Greenhouse heater:

I'm trying to stop an alert notification being sent if the the device returns a 'Null' result, rather than a low temperature reading.

[jlv]

Which of those notifications happen when you get a NULL? Do you have logs of the event happening?

Also: what's the temperature sensor and the device type it is using.

I'm trying to understand why you have the middle case. Is that just to get a repeated notification of continuing low temperatures? (I'm guessing if the heater isn't doing it's job)

[sburke781]

@jlv

Which of those notifications happen when you get a NULL? Do you have logs of the event happening?

This feels like the key to understanding what is happening.... At least the start to understanding the situation....

[UKMedia]

It's the middle one which, as you surmised, is to warn that the heater isn't managing to keep the temp above 3C.

I've tried changing the ElseIF statement to include a minimum condition as well to see if that stops the false notification:

The sensor is a Sonoff Temp Sensor (https://www.amazon.co.uk/gp/product/B08XB2QC3S/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1):

[UKMedia]

Update: Adding the minimum temp has resolved the issue.