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500*c capable Thermistor

Posted by Intensify 
500*c capable Thermistor
January 03, 2018 05:13AM
Found this while searching around that Dyze is using a 500*c thermistor so i been trying to research what they are using so i can just source the part my self rather than using a PT100 + amplifier setup
So far i have found
U1-382-Y1 NTC thermistor

I cant seem to find a temperature table for this thermistor though
[dyzedesign.com]

[www.b3innovations.com] - [cdn.shopify.com]

will any of these work?
Re: 500*c capable Thermistor
January 03, 2018 05:25AM
Bear in mind that you can't get good accuracy and resolution over a wide temperature range using a thermistor, especially if you are using typical 8-bit electronics with only 10 bits of ADC resolution. If you choose the thermistor resistance or change the thermistor series resistor to give good resolution and accuracy at a high target printing temperature, then the ADC probably won't be able to detect that the thermistor is connected when it is at room temperature. For printing at high temperatures, a PT100, PT1000 or thermocouple is a better option.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: 500*c capable Thermistor
January 03, 2018 05:32AM
I think i read somewhere that some one had put a delay of 10 seconds of warmup time before checking the temperature wouldn't that overcome this problem of the low temperature reading?. I lost the link i have 3 windows open with 10+ tabs researching eye popping smiley


[groups.google.com]
[groups.google.com]

Edited 2 time(s). Last edit at 01/03/2018 05:55AM by Intensify.
Re: 500*c capable Thermistor
January 03, 2018 07:00AM
Quote
Intensify
I think i read somewhere that some one had put a delay of 10 seconds of warmup time before checking the temperature wouldn't that overcome this problem of the low temperature reading?. I lost the link i have 3 windows open with 10+ tabs researching eye popping smiley


[groups.google.com]
[groups.google.com]

I think you should first learn about PID in addition to ADC, thermistor linearity (mainly lack of it)... !

I read about a 3D printer setting a house on fire. May be it was this guy ?


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: 500*c capable Thermistor
January 03, 2018 06:56PM
Quote
MKSA
Quote
Intensify
I think i read somewhere that some one had put a delay of 10 seconds of warmup time before checking the temperature wouldn't that overcome this problem of the low temperature reading?. I lost the link i have 3 windows open with 10+ tabs researching eye popping smiley


[groups.google.com]
[groups.google.com]

I think you should first learn about PID in addition to ADC, thermistor linearity (mainly lack of it)... !

I read about a 3D printer setting a house on fire. May be it was this guy ?

Electronics, isn't my strong point more of a programmer. Mostly after a thermister thats capable to around 300* +20*.
My anet a8 doesn't have the connections for 3 pins amp board is my understanding.
I guess i could use a arduino to convert/ translate the singnal into something the anet a8 can use on its 2 pin thermister connection?

Edited 1 time(s). Last edit at 01/03/2018 06:58PM by Intensify.
VDX
Re: 500*c capable Thermistor
January 04, 2018 04:10AM
... I've tested PT100 for temps of up to 800degC - but with 24Bit-ADC's ... don't know, how accurate it would be with 12Bit, but definitely not suited for 8Bit ...


Viktor
--------
Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]
Re: 500*c capable Thermistor
January 04, 2018 02:32PM
The latest release of RepRapFirmware supports PT1000 thermistors connected directly to thermistor inputs, see [duet3d.com]. It's not as good as a PT100 connected to the PT100 daughter board, because the resolution from reading the PT1000 that can be guaranteed is around 0.4C at room temperature, dropping to 0.8C at 400C. In fact we use 2-bit oversampling (to get 14 bits resolution from a 12 bit ADC) to increase the resolution of the displayed temperature to one quarter of these values. But I don't like to rely on oversampling because it assumes that noise in the reading is random, which it almost certainly isn't.

The other issue with connecting a PT1000 sensor to a thermistor input is that gain and offset errors in ADC can introduce large errors in the temperature reading. The SAM4E processor used in the generation 2 Duets has a self-calibrating ADC so those errors are not too bad (about 1C on my test setup). The SAM3X8E used on the legacy Duets doesn't, so the errors will be much worse - although you can compensate for them if you measure them.

In future Duets we're looking at making some improvements to increase the accuracy and resolution of the PT1000 readings, such as using a lower value of series resistor. The value of 4K7 is higher than optimal even for thermistors, because it gives quite low resolution at hot end temperatures.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: 500*c capable Thermistor
January 05, 2018 03:27AM
DC42, why not use a current source, take advantage of the 3 wires, in fact implement the same circuitry and measurement method normally used. PT100 which are common and cheap, could become the standard as there is a real need for higher extrusion temp.
Could be a selling point for the Duet ?

Edited 1 time(s). Last edit at 01/05/2018 03:28AM by MKSA.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: 500*c capable Thermistor
January 05, 2018 09:53AM
Quote
MKSA
DC42, why not use a current source, take advantage of the 3 wires, in fact implement the same circuitry and measurement method normally used. PT100 which are common and cheap, could become the standard as there is a real need for higher extrusion temp.
Could be a selling point for the Duet ?

Interesting idea. However, when using a PT1000 a fixed current source would have to be very accurate, would provide only a marginal improvement in resolution (less less than 2x), and would need to be disabled when using a thermistor.

It wouldn't help when using a PT100 because the main issue then is that the operating current needs to be kept low to avoid self-heating, which means you need an ADC that is accurate at reading small voltages. The MAX31865 chip we use on the daughter board is very good at this. If PT100 were to become standard equipment on 3D printers, we would include the MAX31865 on the Duet. But I think there may be a gradual move to PT1000 instead.



Large delta printer [miscsolutions.wordpress.com], Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Re: 500*c capable Thermistor
January 05, 2018 12:07PM
Quote
dc42
Quote
MKSA
DC42, why not use a current source, take advantage of the 3 wires, in fact implement the same circuitry and measurement method normally used. PT100 which are common and cheap, could become the standard as there is a real need for higher extrusion temp.
Could be a selling point for the Duet ?

Interesting idea. However, when using a PT1000 a fixed current source would have to be very accurate, would provide only a marginal improvement in resolution (less less than 2x), and would need to be disabled when using a thermistor.

It wouldn't help when using a PT100 because the main issue then is that the operating current needs to be kept low to avoid self-heating, which means you need an ADC that is accurate at reading small voltages. The MAX31865 chip we use on the daughter board is very good at this. If PT100 were to become standard equipment on 3D printers, we would include the MAX31865 on the Duet. But I think there may be a gradual move to PT1000 instead.

Self heating is marginal here for the hot end and even the bed. Just that the PT100 seems to be the most common.

Just saw the MAX31865 and indeed it integrates all what is required, 2, 3, 4 wires Kelvin, ADC etc. No need to bother.

So, for PT100, PT1000 to become the standard, integrate it on the Duet, you will set the standard and have a selling point ! smiling smiley


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: 500*c capable Thermistor
January 10, 2018 07:38PM
Interesting information here about thermal sensors the pt100 or 1000 sound really good. Although this does not really help me to much with my Anet a8 electronics it only has the 2 pin plug. I should have been more specific about that in the op.

Quote

The latest release of RepRapFirmware supports PT1000 thermistors connected directly to thermistor inputs, see [duet3d.com]. It's not as good as a PT100 connected to the PT100 daughter board, because the resolution from reading the PT1000 that can be guaranteed is around 0.4C at room temperature, dropping to 0.8C at 400C. In fact we use 2-bit oversampling (to get 14 bits resolution from a 12 bit ADC) to increase the resolution of the displayed temperature to one quarter of these values. But I don't like to rely on oversampling because it assumes that noise in the reading is random, which it almost certainly isn't.
Does this work with the anet a8? Is there a guide?

Edited 3 time(s). Last edit at 01/10/2018 09:53PM by Intensify.
Re: 500*c capable Thermistor
January 15, 2018 04:00PM
I have b3's pico hotend and 500C thermistor. It is a well designed unit.
Re: 500*c capable Thermistor
January 17, 2018 07:12AM
Quote
hayedid
I have b3's pico hotend and 500C thermistor. It is a well designed unit.

What printer do you have this attached to/ what electronics/ software does it run?

I really want to print polycarbonate i think its a really cool functional plastic and being clear it looks good to.

Edited 1 time(s). Last edit at 01/17/2018 07:19AM by Intensify.
Re: 500*c capable Thermistor
September 27, 2020 01:45PM
before attempting to run a anet a8 at 500c PLEASE tell me you upgraded it to blv mod with 2020 aluminium extrusions and you are not using acrylic. That would just be an accident waiting to happen.....stock a8s burned houses.... adding 500c to that is just a bad idea.
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