How to enter a user defined thermistor table?

[Fabio]

I've been dialling in the Max v2 gradually over the last week with the E3D hot end and starting to get there.. However I've found the thermistor they supply to a bit wacky - I've had to set the temps for PLA right up to get good prints even though I have defined table 8 in the Config.h file as per E3D's recommendations.

After seeing a few posts I decided to upgrade the thermistor for a M3 stud type - I ordered two and they arrived from the US in GB this morning. They are a EPCOS 100K Thermistor (B57560G1104F)

Now I've looked up the table on the reprap wiki and it's listed as this:

// EPCOS 100K Thermistor (B57560G1104F)
// Made with createTemperatureLookup.py (http://svn.reprap.org/trunk/reprap/firm ... eLookup.py)
// ./createTemperatureLookup.py --r0=100000 --t0=25 --r1=0 --r2=4700 --beta=4092 --max-adc=1023
// r0: 100000
// t0: 25
// r1: 0
// r2: 4700
// beta: 4092
// max adc: 1023
#define NUMTEMPS 20
short temptable[NUMTEMPS][2] = {
{1, 821},
{54, 252},
{107, 207},
{160, 182},
{213, 165},
{266, 152},
{319, 141},
{372, 131},
{425, 123},
{478, 115},
{531, 107},
{584, 100},
{637, 93},
{690, 86},
{743, 78},
{796, 70},
{849, 60},
{902, 49},
{955, 34},
{1008, 3}
};


what is puzzling me at the moment is exactly how to enter this into the Config.h file correctly..

If I changed this:

#define USER_THERMISTORTABLE0 {}

to this:

#define USER_THERMISTORTABLE0 {\
{1,821},{54,252},{107,207},{160,182},{213,165},{266,152},{319,141},{372,131},{425,123},{478,115},\
{531,107},{584,100},{637,93},{690,86},{743,78},{796,70},{849,60},{902,49},{955,34},{1008,3} }

and then

change this line:

#define NUM_TEMPS_USERTHERMISTOR0 28

to this:

#define NUM_TEMPS_USERTHERMISTOR0 20

use table 5 would this then be correct? Would that be all i need to do?

Thanks in advance!

[Fabio]

Anyone?

I need to know whether the values need the 4 and 8 multipliers added or not? I do not know at present how to check if the table is a sprinter one which needs those multipliers according to the documentation..

I'm guessing that they do?

cheers

[teoman]

The values do not look like they need multipliers. (From what i see).

Do you have athermocouple that you could experiment and verify?

[Fabio]

I've got a meter thermocouple combo on the way to manually test things - in the meantime my research has thrown up that existing table 1 might be a good place to start as it's 'supposed' to be for generic epcos 100k therm's so I'll try that and see before I go entering the table manual for a user defined one

[teoman]

I think that setting is the one i use for the screw in thermistor i got off ebay.

[Fabio]

overhauled the E3D today and fitted the M3 therm - I used table 1 and the difference in printing is now literally like night and day!

It sort of confirms my suspicions that the stock e3d therm' was way under-report actual temps at the nozzle by a large margin.

very happy chappy right here and I'm gonna get a few of these therm's as spares