Pic NTC calculation

I needed to calculate a table, for a pic project, to use a thermistor (NTC) in a resistive divider circuit.
So, I made an excell spreadsheet to make this.
The spreadsheet is attached to this post.

You must inform:
- the pic's supply voltage;
- the adc resolution (8 or 10 bits - if 10 bits, must change the formating of hex column);
- the temperatures;
- the resistance of the ntc, at the temperature;

The circuit is a resistive divider, with the first resistor with a value of 1K1 1% and the second resistor composed of the ntc in paralel with an 7K5 1% resistor.

Observation: I have made this spreadsheet using openoffice and exported it in excell format. The formula used to print the hexadecimal values was:
=DECAHEX(G22;2)
This to print the hexa of cell G22, showing it using 2 characteres.
If you use MS excell, you must change the formula.

Help this can be useful.

Added a graphic and some comments to the columns headers.

Hi, Ssaguiar

Could you explain which kind of file this is ???

couldn't succeed to open it whether the used program ( open office, Excel, ... etc,etc ...)

Thanks

Alain

Acetronics said:

Hi, Ssaguiar

Could you explain which kind of file this is ???

couldn't succeed to open it whether the used program ( open office, Excel, ... etc,etc ...)

Thanks

Alain

Click to expand...

Hi, Alain.
I used the BRoffice 3.X wich is the OpenOffice, in Bazilian Portuguese.
I exported the file in MS Excell format, but, as I don't have it installed, I could not test it, but I can open and edit it using BROffice (OpenOffice 3.x).
Now, I attached the file thermistor.zip, wich contains the file thermistor.ods, in OpenOffice format.

Please, let me know if it works.

Sergio

Hi, Ssaguiar

Finally got it ...

1) unzipped your file with UltraZip ( a free dezipper )
2) unzipped the produced file with 7 zip ( another Free dezipper )
and 3) Yess , got an Open Office file ...

Alain

PS: here is a little document explaining how to achieve a good linearization ... but that need a translation.

I am glad you got it.
I don't understand why you had to use 2 unzipers (UltraZip and 7zip), because I used only the winrar to compress the file in zip format.
The most important is that it worked for you.
Let me know if the spreadsheet is usefull.

Sergio

PS: I see that you like Asterix. My avatar is Asterix, in several places.
I will upload it asap.
I like it since I was a student at Marseille, in France, a loooong time ago (1971).

ssaguiar said:

I don't understand why you had to use 2 unzipers (UltraZip and 7zip), because I used only the winrar to compress the file in zip format.
Sergio

Click to expand...

I do not understand nor ... but it works !!!

Thanks once more
Alain

!!! changed the download

Hi ssaguiar, not bad ... quite usefull. I just changed the spreadsheet so I get 10bit and 16bit values in HEX as well. I altered the formula to =DEC2HEX(G3,(CEILING((B6/4),1))). Thank you for sharing!