Disappearing HeaterMeter temperature trace of probe at low temperature....

[Geert Roelofs]

I live in the Netherlands and am currently preparing some smoked salmon with a cold smoke generator placed in my ceramic kamado. Since ambient temperatures are pretty low right now (it's freezing a bit) I am using my HeaterMeter to monitor the pit temp as well as the ambient temperature. The ceramic of my Monolith kamado is very well isolating, so no worries that my salmon will freeze. Pit temperature is 42 F (5,6 Celsius). But......the ambient temperature is approx. 27 Fahrenheit ( -2,9 Celsius). What I see right now is that the temperature trace of probe 2 (external/ambient) disappears when I am refreshing the page. It will start writing and being visible again and as long as I don't refresh it will stay visible. (you see the short green line at the lower end). Could this be a bug in the software? In case Bryan is reading this, or in case someone else ran into this, I am looking forward to receive your comments! Thanks in advance!

 

[Bryan Mayland]

Hey Geert, nice customization of the home page you've done there! Also a really good explanation of your issue which made it easy to figure out what is going on.

The reason the temperatures disappear is that the persistent database can't store negative numbers. When you're streaming the data "live", the graph is built directly from the incoming stream from the HeaterMeter, which can report negative numbers. When you refresh the page, it pulls the history from the database, which doesn't have the negative values any more so the data disappears.

It is possible that I can extend the database to hold negatives but I am not sure if there's other code in the pipeline that expects no negative values to come out of the database so don't hold your breath for a quick fix.

 

[JKalchik]

<chuckle> What, you can't just change an unsigned to a signed field type? What could possibly be the harm in that?

 

[Geert Roelofs]

Hey Geert, nice customization of the home page you've done there! Also a really good explanation of your issue which made it easy to figure out what is going on.

The reason the temperatures disappear is that the persistent database can't store negative numbers. When you're streaming the data "live", the graph is built directly from the incoming stream from the HeaterMeter, which can report negative numbers. When you refresh the page, it pulls the history from the database, which doesn't have the negative values any more so the data disappears.

It is possible that I can extend the database to hold negatives but I am not sure if there's other code in the pipeline that expects no negative values to come out of the database so don't hold your breath for a quick fix.

Hey Bryan, thanks a lot for your swift reply! I understand your explanation and did not hold my breath but kept going on cold smoking.
In order to still see the ambient temperature in the graph, I didn't refresh for a period of 12 hours, hence still seeing both pit and ambient temperature in the graph.

Anyhow, the salmon is ready now and sealed in vacuum for the next 48 hours, after which it's ready to enjoy eating it! (on the pics in the right hand corner, you see the black housing of the HeaterMeter, the blue "box" you see is a 12V 30.000 mAh rechargeable battery which I always use with the HeaterMeter. It gives me more "freedom").

Whenever there would be a software fix for this unique situation, I will of course be happy to adapt it. Thanks and Happy Holidays!