now that e3d have finally released there pt100 amplifier board for their pt100 heater block, I’m going to try and get it set up and working with smoothie on Monday.
Just wondering if anyone has made any progress on this already to get me started?
Imported from wikidot
Do you have the specs of that sensor ? Specifically the beta value ?
Hi Arthur,
E3D say that using Marlin, there are defined PT100 values in the thermistor file. I looked it up and got this:
#if (THERMISTORHEATER_0 == 20) || (THERMISTORHEATER_1 == 20) || (THERMISTORHEATER_2 == 20) || (THERMISTORBED == 20) // PT100 with INA826 amp on Ultimaker v2.0 electronics
/* The PT100 in the Ultimaker v2.0 electronics has a high sample value for a high temperature.
This does not match the normal thermistor behaviour so we need to set the following defines */
#if (THERMISTORHEATER_0 == 20)
#endif
#if (THERMISTORHEATER_1 == 20)
#endif
#if (THERMISTORHEATER_2 == 20)
#endif
#if (THERMISTORBED == 20)
#endif
const short temptable_20[][2] PROGMEM = {
{ 0*OVERSAMPLENR , 0 },
{ 227*OVERSAMPLENR , 1 },
{ 236*OVERSAMPLENR , 10 },
{ 245*OVERSAMPLENR , 20 },
{ 253*OVERSAMPLENR , 30 },
{ 262*OVERSAMPLENR , 40 },
{ 270*OVERSAMPLENR , 50 },
{ 279*OVERSAMPLENR , 60 },
{ 287*OVERSAMPLENR , 70 },
{ 295*OVERSAMPLENR , 80 },
{ 304*OVERSAMPLENR , 90 },
{ 312*OVERSAMPLENR , 100 },
{ 320*OVERSAMPLENR , 110 },
{ 329*OVERSAMPLENR , 120 },
{ 337*OVERSAMPLENR , 130 },
{ 345*OVERSAMPLENR , 140 },
{ 353*OVERSAMPLENR , 150 },
{ 361*OVERSAMPLENR , 160 },
{ 369*OVERSAMPLENR , 170 },
{ 377*OVERSAMPLENR , 180 },
{ 385*OVERSAMPLENR , 190 },
{ 393*OVERSAMPLENR , 200 },
{ 401*OVERSAMPLENR , 210 },
{ 409*OVERSAMPLENR , 220 },
{ 417*OVERSAMPLENR , 230 },
{ 424*OVERSAMPLENR , 240 },
{ 432*OVERSAMPLENR , 250 },
{ 440*OVERSAMPLENR , 260 },
{ 447*OVERSAMPLENR , 270 },
{ 455*OVERSAMPLENR , 280 },
{ 463*OVERSAMPLENR , 290 },
{ 470*OVERSAMPLENR , 300 },
{ 478*OVERSAMPLENR , 310 },
{ 485*OVERSAMPLENR , 320 },
{ 493*OVERSAMPLENR , 330 },
{ 500*OVERSAMPLENR , 340 },
{ 507*OVERSAMPLENR , 350 },
{ 515*OVERSAMPLENR , 360 },
{ 522*OVERSAMPLENR , 370 },
{ 529*OVERSAMPLENR , 380 },
{ 537*OVERSAMPLENR , 390 },
{ 544*OVERSAMPLENR , 400 },
{ 614*OVERSAMPLENR , 500 },
{ 681*OVERSAMPLENR , 600 },
{ 744*OVERSAMPLENR , 700 },
{ 805*OVERSAMPLENR , 800 },
{ 862*OVERSAMPLENR , 900 },
{ 917*OVERSAMPLENR , 1000 },
{ 968*OVERSAMPLENR , 1100 }
};
#endif
I have the E3D breakout board which converts the signal into this appropriate format. It requires 0v, 5V and signal.
Will I be able to use the above code in smoothie somewhere?
I really don’t know that much about what I’m doing, but here’s what I’ve found out for anyone else that’s interested.
Using E3D’s PT100 kit with their amplifier board isn’t yet possible. The amplifier board seems to do the ADC conversion onboard. So smoothie just needs an analogue input pin, then a separate piece of code to call up the reading and convert that to degrees using either a table or a derived formula that’s different from the beta and steinhart formulas.
This sounds like an easy enough job to do, but I have no idea where to begin and am worried about ensuring the code properly references everything it needs to. Is anyone able to lend me a hand on this?
Cheers!
Has anyone made progress on this yet?
Is there anything I can do to help?
Any progress on this I have used these amp boards on another printer and work realy well the mounting of the sensor in ver robust on v6 hotend , and seems to give much more stable temps than thermistors when printing , it seems we have a table of outputs to temperatures above from marlin fw
Maybe it is possible by using the MAX31865. I’m sure that the smoothie can use the MAX31855 for reading thermocouple thought SPI interface, so maybe using this MAX31865 we can read PT100 in a easy way. Not sure of course.
I’ve seen around some breakout board with the MAX31865 chip. I’m looking for buying one to test to, but it is quite expensive (30usd + shipping). So i just ask if my idea is good and it can works without modification in the firmware (out of my skill). Someone with more experience can give me an advice?
Thank you and cheers!
edit. look at this: www playingwithfusion com/productview.php?catid=0&pdid=26