Question : Thermistors & Thermocouples Makerbot Rep 2x Settings?

[David Clunie]

So sometime last week I was playing around with using those glass coated "thermistors" (not sure exactly on the terminology) and I think I remember hearing something about you have to tell the firmware which you're using either direct wires aka "thermocouples"  ? or if you're using those glass beaded thermistors..

The reason I'm asking is it seems that the temp when using the default makerware and makerbot rep 2x is for direct wires as with the glass bead it seems the temp isn't regulated correctly.  When I was using the glass bead the heater cartridge was extremely hot, and even produced smoke from i think it starting to smoldering the wire coverings, so I stopped it and went back to the direct wire solution which seems fine in the regulation of the heat.  

So does one have to change something in the firmware, is it possibly with the base firmware and makerware? or does one have to upgrade to marlin and use an alternate method like repG Cura simplify3d to slice and print your models.  

Feel free to correct any of my terms or inaccuracies.  

Also is there a definitive guide tutorial on how to upgrade to marlin, etc. with the rep 2x? would like to get out from under the yoke of the makerbot peeps with my rep 2x.

-david c.

[Ryan Carlyle]

The Mightyboard used in all Replicator 2/2/2x/clone bots is NOT able to read thermistors for hot ends. It uses a thermistor for the HBP but MUST use thermocouples for the extruders. 

Thermistors and thermocouples use fundamentally different sensing mechanisms and thus require different converter chips on the board. It's a hardware issue -- software alone can't do it.

Converting a Mightyboard-based bot to run Marlin requires entirely replacing the board with RAMPS. Putting Marlin directly onto the Mightyboard would be a significant software porting effort and is, to be blunt, pretty dumb since the performance is worse than Sailfish.

Putting RAMPS in a Replicator requires replacing most of the electrical components since RAMPS is a ~12v system and Mightyboards are 24v systems. That means the heaters, fans, motors, etc are all spec'd wrong. You're basically building a new bot -- just reusing the frame and gantry.

[Ryan Carlyle]

Incidentally, you can use Makerware to export gcode and you can use RepG or GPX to convert gcode from any other slicer to x3g code to run on a Makerbot. There's some fidgetiness with slicer-specific gcode commands but in general you can use whatever slicer you want with any machine.

On Tuesday, August 5, 2014 12:46:44 PM UTC-5, David Clunie wrote:

[David Clunie]

Hmmm Interesting.  I could have swore some of the community switched over to marlin for the makerbot (wingcommander?) but if its as you say then I'll just stick with the default crap and use thermocouples.  

Which I supposed brings me to my next question, does anyone know if you can use a thermocouple with the e3d v6 hot ends?  They come with a glass bead and a screw to hold em in, but i can certainly stuff the thermocouple wires in there and secure them down the same way....  I would expect you could do this as its the same contact point...  (if not i suppose i could drill in a hole if needed to a better area on that hot end.

-david c.

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[Ryan Carlyle]

Would be super easy to put a thermocouple in an E3D v6. You can secure it the same was as the stock thermistor (stuff in the pocket and clamp w/ set screw) or you can take an M3 thermowell style like MBI uses, and screw that into the hole intended for the clamp screw. (I actually picked up a couple of their hot blocks for my CoreXY type bots since the heater cartridge clamp style is so nice.)

You don't like Sailfish? 

[Joseph Chiu]

Thermistors work on varying resistance over temperature.  It's placed in series with an additional resistor to create a voltage divider between +V and ground, and that divider's output is read by an ADC.

Thermocouples create weak a voltage potential between the two dissimilar metals - that voltage is directly fed into an amplifier/converter.   A thermistor does not generate such a voltage.

Marlin has not been ported to the Mightyboard AFAIK.  Not impossible, but I don't think anyone has bothered.

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[Ryan Carlyle]

A quick googlin' showed some people talking about pinout differences between the two boards, but nothing concrete. 

Unless you want auto-calibration on a Delta, I don't see much reason to use Marlin over Sailfish. There's a big differential in code quality, and RAMPS vs Mightyboard seems pretty comparable to me in terms of capabilities. Same shitty processor in both.

If you really want to get away from Makerbot type tech, I'd recommend going with something newer like a Smoothie / Azteeg x5. I have no experience with it though.

[David Clunie]

thanks for all the info.  I think overall i was just under the impression, and apparently incorrectly, thinking that marlin was better than sailfish.  I might have to go back and watch the wingcommander videos again, or watch Thomas's videos again as I could have swore people were upgrading their makerbot to something other than the stock firmware for more control and better results.  

but i suppose as long as my hot end adapter with carls aluminum carriage works i'll just use the e3d hot end with the default thermocouples.  

(i also have a rostock v2 max but I haven't attempted any customizing on that yet, but i do have two e3d v6 hot ends for that printer as well and hope to turn it into a dual head extruder as well, currently its just a single extruder.)

-david c.

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[Ryan Carlyle]

Sailfish is the upgrade they were talking about, pretty sure. It's better than MBI's stock firmware.

[Jetguy]

+1

The Smoothie board project and firmware has reached a very good level of documentation, support, features, and just works. Now, it may not yet be novice proof but with it, you now can go thermistor or Thermcouple using the Adafruit MAX31855 thermocouple amp breakout.

 

So on a technical level, this would bring the machine right into the best leading class controller I've put hands on. I wish sincerely that the Replicape (based on a BeagleBone Black shield) was at the same maturity level.

 

My only comment is that right now today, nobody has quite given me the performance I can get out of Sailfish firmware on a Mightyboard. the secret is JKN tuning that Dan and Jetty went through who know how many hours of testing. To my knowledge- nobody else in any other controller has picked up on this key tuning aspect and it's critical to print quality. As always, that's just my opinion but take it as that.

If I had JKN on smoothie, it would be the holy grail of current offerings.

 

Ethernet, graphic LCD support, even wireless Bluetooth using the Adafruit UART module. It's just a working dream and it's amazing how good it works.

 

That said, Sailfish and mightyboard is the "gold standard". It too has the option for Bluetooth UART and coupled with a Toshiba flash Air, certainly gives you competing connectivity and features- but most of all print quality.

Until something massively tumps that, I keep that as my go to controller of choice when building a new machine.

 

 

Basically, I'm saying I think you are nuts for trying to patch in some Reprap firmware or controller when you have the hardware to run the best firmware out there.

I may not love everything about the mightyboard series, but coupled with Sailfish firmware- if you get your hardware right, that combo will out print nearly everything out there.

[David Clunie]

yup, i think that is where i goofed up initially refering to marlin instead of sailfish, that is I should have been asking for a detailed upgrade process from stock makerbot (i think i'm on 7.1) firmware to sailfish...

-david c.

[Ryan Carlyle]

http://www.makerbot.com/sailfish/install/