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SoliForum - 3D Printing Community → Hacks & Mods → E3D TC upgrade?
Where is the best place to buy the conversion board to use TC with e3d instead of thermistor on SD3? Will any k-type tc work or is there something special about tc code in Marlin/conversion board that needs E or J type TC?
Thanks
Can't help with your question, but I'm curious - what are you planning to print that needs over 300C?
So far no plans for over 300C, however, i broke my thermister; wires are way to thin and i have unlimited suply of 24AWG TC wire... So it seems like a more rugged installation with long term benefits/upgrades to newer printing media. Currently avaiable fillaments max out at 300, but who knows what future may bring, may be solder wire?
The TC code in Marlin is based on having a MAX6675 (EOL'ed, now superseded by the MAX31855) or AnalogDevices AD595 IC connected - the type of thermocouple connected to it is then entirely based on what MAX31855 you have connected. I.e, its not designed to go through a lab-grade OpAmp and doing cold-junction conditioning - Marlin instead expects you to have an IC that does all that for you and simply spits out the corrected/calibrated tempreature upon request...
The bulk of MAX6675 or MAX31855 chips you find in "breakout board", will be the K-Type... And the AD595 is *only* good for K-types (the 594 does J-Types). The max-delta-T on each type of thermo couple chages, but for a K-Type, it hovers around the 1.5°C delta up to 400, and after 600 starts almost climbing in a log fashion (600 is 2.4, 800 is 3.2, 1000 is 4.0 etc).
E-Type is worse for the temp ranges concerned with printing, and a J-type is indentical in error curve of a K-Type but tops out at just over 600 anyway. If you wanted the lowest delta across the widest range, R or S are the ones to go for, with a max delta of 1.0°C across the most used temp ranges, and only starts log climbing above 1400°C. So - You can use 'any' Thermocouple, as long as you add the 'appropriate' MAX or AD594/595 circuit (I personally don't like the AD595's.. so would err to a MAX31855 myself...) .
If you do your own MAX31855 circuit, you can get the R or S type IC and use the respective TC's (bearing in mind R stands for "Rudely Expensive" and S for "Stupidly Expensive".... 
)
In terms of Thermistor vs Thermocouple - remember that a Thermistor is usually more accurate than a Thermocouple (depending on conditioning), and thermocouples are subject to high noise distortion due to their much smaller voltage. But thermocouples can do higher temps... from a 'reading' prespective a TC has a mostly linear response curve and can be interpolated but a Thermistor has a non-linear curve and needs map tables.... So its all a tradeoff really as to whats the best approach for the specific application.
The TC code in Marlin is based on having a MAX6675 (EOL'ed, now superseded by the MAX31855) or AnalogDevices AD595 IC connected - the type of thermocouple connected to it is then entirely based on what MAX31855 you have connected. I.e, its not designed to go through a lab-grade OpAmp and doing cold-junction conditioning - Marlin instead expects you to have an IC that does all that for you and simply spits out the corrected/calibrated tempreature upon request...
The bulk of MAX6675 or MAX31855 chips you find in "breakout board", will be the K-Type... And the AD595 is *only* good for K-types (the 594 does J-Types). The max-delta-T on each type of thermo couple chages, but for a K-Type, it hovers around the 1.5°C delta up to 400, and after 600 starts almost climbing in a log fashion (600 is 2.4, 800 is 3.2, 1000 is 4.0 etc).
E-Type is worse for the temp ranges concerned with printing, and a J-type is indentical in error curve of a K-Type but tops out at just over 600 anyway. If you wanted the lowest delta across the widest range, R or S are the ones to go for, with a max delta of 1.0°C across the most used temp ranges, and only starts log climbing above 1400°C. So - You can use 'any' Thermocouple, as long as you add the 'appropriate' MAX or AD594/595 circuit (I personally don't like the AD595's.. so would err to a MAX31855 myself...) .
If you do your own MAX31855 circuit, you can get the R or S type IC and use the respective TC's (bearing in mind R stands for "Rudely Expensive" and S for "Stupidly Expensive"....
In terms of Thermistor vs Thermocouple - remember that a Thermistor is usually more accurate than a Thermocouple (depending on conditioning), and thermocouples are subject to high noise distortion due to their much smaller voltage. But thermocouples can do higher temps... from a 'reading' prespective a TC has a mostly linear response curve and can be interpolated but a Thermistor has a non-linear curve and needs map tables.... So its all a tradeoff really as to whats the best approach for the specific application.
Thanks. Tons use useful stuff. Your post should be put in a wiki or something...
Thanks. Tons use useful stuff. Your post should be put in a wiki or something...
So do it! Wikis are editable by anyone!
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