Thermistor component Range
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Thermistor component Range
Hi,
I'm working on an extruder machine to recycle water bottle caps into 3D printer filaments.
I figured i could use one of my ramps board to drive the whole contraption. So far accesing the ramps pins via flowcode works great.
Right now i'm hitting a stag with the thermistor component as it only ranges from -25c to 125c. For the purpose of the project i'd need it to range to 300c.
Is there a way in flowcode to increase the range of this component ?
Thank you already for any clues i could get .
I'm working on an extruder machine to recycle water bottle caps into 3D printer filaments.
I figured i could use one of my ramps board to drive the whole contraption. So far accesing the ramps pins via flowcode works great.
Right now i'm hitting a stag with the thermistor component as it only ranges from -25c to 125c. For the purpose of the project i'd need it to range to 300c.
Is there a way in flowcode to increase the range of this component ?
Thank you already for any clues i could get .
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Re: Thermistor component Range
There is an excellent description of usage on the Adafruitv site https://learn.adafruit.com/thermistor/overview
They describe the range of the thermistor as going to 125C but if you have a device capable of more then the techniques used the should be applicable.
Martin
They describe the range of the thermistor as going to 125C but if you have a device capable of more then the techniques used the should be applicable.
Martin
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Re: Thermistor component Range
Hi Martin,
Thanks for your reply.
I did not mentionned it in my initial post but i've already been playing around with adafruit's tutorial.
Converting it in flowcode and downloading it on a regular Arduino Uno or Mega works fine.
But as soon as i mount the RAMPS shield (that i know is not broken)on the Mega, hook up the thermistor on the T1 pin (An 14 on Mega), my readings gets totaly off.
The RAMPS uses a integrated 4.7K resistor instead of the 10K of the tutorial.
http://domoticx.com/wp-content/uploads/ ... schema.png
Yet when i use the thermistor EBM003 component in flowcode i get a good readings of that same thermistor, but max out to 125c when i need to go all the way to 300c or 270c.
Which is why i'd like the keep the EBM003 component and just increase its range.
CorteX
Thanks for your reply.
I did not mentionned it in my initial post but i've already been playing around with adafruit's tutorial.
Converting it in flowcode and downloading it on a regular Arduino Uno or Mega works fine.
But as soon as i mount the RAMPS shield (that i know is not broken)on the Mega, hook up the thermistor on the T1 pin (An 14 on Mega), my readings gets totaly off.
The RAMPS uses a integrated 4.7K resistor instead of the 10K of the tutorial.
http://domoticx.com/wp-content/uploads/ ... schema.png
Yet when i use the thermistor EBM003 component in flowcode i get a good readings of that same thermistor, but max out to 125c when i need to go all the way to 300c or 270c.
Which is why i'd like the keep the EBM003 component and just increase its range.
CorteX
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Re: Thermistor component Range
What is the formula you used for thermistor?
Best to upload your flowchart.
I'm using a formula that works for any value of pull-up and thermistor value.
It seems to be nice and accurate.
I can check your formula for 4k7 with your themistor.
You will need to state thermistor value at 25C and Beta for the range required.
Best to upload your flowchart.
I'm using a formula that works for any value of pull-up and thermistor value.
It seems to be nice and accurate.
I can check your formula for 4k7 with your themistor.
You will need to state thermistor value at 25C and Beta for the range required.
Martin
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Re: Thermistor component Range
Hi thanks a lot for jumping in.
i figured out my issue.
I used the following formula to calculate the Thermistor Resistance: R = 10K*ADC / (1023 - ADC)
And the inverse of the following minus 273.15 to calculate the temperature in C:
My issue came from the fact that i did not convert to floats every non-float variables and constants. I did it for some variables and not others, obliviously assuming that if i didn't get an error at validation it meant that the compiler would by default do the convertion.
I was wrong.
I haven't tried yet to heat up the thermistor all the way to 270C (i'm using regular dupon wires at the time), but i got a clean and coherent reading all the way to 150c before my wires started to smoke....
If interested I can still upload the flowchart here
i figured out my issue.
I used the following formula to calculate the Thermistor Resistance: R = 10K*ADC / (1023 - ADC)
And the inverse of the following minus 273.15 to calculate the temperature in C:
My issue came from the fact that i did not convert to floats every non-float variables and constants. I did it for some variables and not others, obliviously assuming that if i didn't get an error at validation it meant that the compiler would by default do the convertion.
I was wrong.
I haven't tried yet to heat up the thermistor all the way to 270C (i'm using regular dupon wires at the time), but i got a clean and coherent reading all the way to 150c before my wires started to smoke....
If interested I can still upload the flowchart here
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Re: Thermistor component Range
Hi cortex,
I'm glad you have figured out your issue.
If you had not, then I have got a calculation that works with Flowcode and is a single calculation.
I will post my calculation if interested?
I'm glad you have figured out your issue.
If you had not, then I have got a calculation that works with Flowcode and is a single calculation.
I will post my calculation if interested?
Yes please, as it will be handy for anyone else who had the same issue as you.cortex wrote:If interested I can still upload the flowchart here
Martin
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Re: Thermistor component Range
Hi Medelec,
I'll be glad to check out your calculation, i'm always interested in learning new stuff.
You can find my working flowchart here (flowcode 7): CorteX
I'll be glad to check out your calculation, i'm always interested in learning new stuff.
You can find my working flowchart here (flowcode 7): CorteX
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Re: Thermistor component Range
Hi cortex.
The calculation I used is:
Where it does not state a variable type, I have used Constants.
Note: The .0 in 1024.0 is vital as it negates the requirement for int2float.
Without .0 the temperature value will be completely wrong!
Which is what you mentioned was the issue with your flowchart.
Have yo got a link to the thermistor you are using?
One way to check accuracy is to use a fixed 10K resistor with a good tolerance e.g 1% in place of the thermistor.
Check the temperature displayed is 25C.
Also, check the resistance of thermistor from the datasheet at the extremes of temperature you wish to measure.
Used fixed resistors for those values and check the temperature displayed is within expected ranges.
The calculation I used is:
Code: Select all
TemperatureFloatVariable = 1 / ((log (SeriesPullUpResistanceValue / (1024.0 / ADCIntVariable - 1) / ThermistorResistanceAt25C)) / BetaValue + 1 / (25 + 273.15)) - 273.15
Note: The .0 in 1024.0 is vital as it negates the requirement for int2float.
Without .0 the temperature value will be completely wrong!
Which is what you mentioned was the issue with your flowchart.
Have yo got a link to the thermistor you are using?
One way to check accuracy is to use a fixed 10K resistor with a good tolerance e.g 1% in place of the thermistor.
Check the temperature displayed is 25C.
Also, check the resistance of thermistor from the datasheet at the extremes of temperature you wish to measure.
Used fixed resistors for those values and check the temperature displayed is within expected ranges.
Martin
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Re: Thermistor component Range
Hi Cortex/Martin!
What kind of Termistor are you using, Please.
Br Jorgen
What kind of Termistor are you using, Please.
Br Jorgen
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Re: Thermistor component Range
Hi Jorgen,
I'm just using a cheap standard 10K ntc thermistor.
Nothing special about it at all.
I'm just using a cheap standard 10K ntc thermistor.
Nothing special about it at all.
Martin
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