For your information:
In monitor mode of the da Vinci 1.0 Pro I got:
330k-->29°C
99.8k-->62°C
46.9k-->96°C
With these data the RRF configuration tool calculated:
R25: 388403 Ω
β: 3670 K

Best regards

Uli

Ahh, yes, it works - Thanks!

I did not find such a setting. However, with the Vivaldi browser it works now.

Hi,
I'm using a 15inch laptop. So, in Settings/System editor, I cannot see the complete file list at once. Scrolling down I can see the other (formerly "hidden") files - but only for a very short time. May be a second or less. Then the formular is actualized and the list jumps to it's beginning (scrollbar at the top). This makes it nearly impossible to access any "hidden" file at the lower part of the list.

Browser: actual Firefox
Firmware Name: RepRapFirmware for Duet 2 WiFi/Ethernet
Firmware Electronics: Duet WiFi 1.02 or later
Firmware Version: 2.02(RTOS) (2018-12-24b1)
WiFi Server Version: 1.22
Web Interface Version: 1.22.6

Is there a solution?

Regards,

Uli

And here are the differences between table and calculated temperatures for the calculations according to Steinhart-Hart:

Now I did the calculations for the Steinhart-Hart equation:
1/T = a + bln(R) + c(ln(R))^3
Unfortunately, I could not find a fast way to plot the difference between calculated temperature and these from the table as function of temperatur. Here I only compare the temperature from table (thermistor #1 - table) with these calculated with the optimized Steinhart-Hart coefficients using all points (thermistor #1 - calc) or selected triples (25°-180°-250° - calc, 30°-65°-100° - calc):

I learned: As dc42 mentioned above, one should always use the Steinhart-Hart equation. The availabilty of a R-T table is very helpful. But even the coefficients obtained using the resistance at 30°C, 65°C and 100°C lead to a good description of R vs T at higher temperatures. And these can be easily obtained using a water bath and a thermometer.

I will compare it on Monday...

OK, the last sentence should better be this one:

Then I subtracted Tcalc from Tmerlin (for each Tmarlin)

In Convert Marlin Thermistor Table To M305 you provided the formula
R = 4700 * A / (1024 - A)
for the calculation of the R values. That I did and obtained the T vs. R dependenc. Then I minimized (Simplex algorithm)
(Tmerlin - Tcalc)^2
with
Tmerlin - temperature calculated from Merlin temperature table
Tcalc = B / ln(R/ri)
I did it for all values of the merlin table (60+ points) and for selected triples (three R/T values)
B and ri are the varibles to optimize.
With the optimized values I recalculated the temperatures (Tcalc) for all R values in the Marlin temperature table. Then I subtracte Tcalc from Tmerlin (for each R).

For my calculation of the residuals I used a separate application with a simplex algorithm, not the RRF configuration tool. And I assume the residuals might be comparable when I use the Steinhart-Hart equation
1/T = a + bln(R) + c(ln(R))^3

OK, I now understand how to put the values in the RRF configuration tool, thanks.

Regards

Uli

Hi,

I'm wondering if the thermistor calculation in the RRF tool could be enhanced. According to
T = B / ln(R/ri)
I approximated T as f(R) of Marlin thermistor #1 for all values in the thermistor table as well as for three selected points as in the RRF configuration tool. With the RRF configuration tool one of the three points has to be the resistance at 25°C. In the attached figure you may find the temperature dependent residuals (measured - calculated temp). For the series labelled Thermistor #1 all points of the thermistor table were used in order to calculate B and ri, for the other series only the resistance at temperatures in the legend were used. As expected, using an other than the 25°C resistance as starting value leads to a significantly higher precision in the temperature range. So can the behaviour of the RRF configuration tool can be changed in order to accept temperatures other than 25°C for the first point?

BTW, what is the meaning of (beta) in the RRF configuration tool? B in the equation above? Or b in
1/T = a + bln(R) + c(ln(R))^3 ?

Regards

Uli