Cumulus Support

Hi,

For some time now I have not used the second order temperature multiplier TempMult2 since I had not characterised my sensor after a replacement. I have done this now and find it could do with a little tweaking.
I thought I would just check my understanding of TempMult2 ini file parameter and check it is working before comitting to it.

The temperature outside just happened to be 2.0 degC, so I set TempMult2=0.5 which should have given me 0.5 * 2.0 * 2.0 = 2.0 but it didn't... I got 4.0

TempMult and TempOffset both seem to produce the correct results.

Are we sure TempMult2 is working? Is anyone else using it okay?

Adrian Hudson wrote: ↑Mon 20 Jan 2025 11:37 pm The temperature outside just happened to be 2.0 degC, so I set TempMult2=0.5 which should have given me 0.5 * 2.0 * 2.0 = 2.0 but it didn't... I got 4.0

mult2 * val² + mult * val + offset

0.5 * 2.0 * 2.0 + 1 * 2.0 + 0 = 4.0

0.5 is a massive second order correction, at 20°C you would be getting a result of 220°C!

Hi Mark,

Yes, thanks. Durr. I had left TempMult as default (1) so I discounted it altogether. In my defence it was late last night.

(I realise the second order figure is ludicrous - I was just using a number that would work with the 2 degC that I happened to have outside at the time. The actual figure is around -0.0002)