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I am making the switch to independant power and temp.

Posted: Mon May 20, 2013 6:42 pm
by Flateric
I am switching over to individual subsystems for the heated bed and hot-end each with their own digital temp controller and individual power source. I have all of this working great these up wired and working great (really nicely actually)

My question is simply this, what is the best way to disable all checks and safty measures so that the firmware will let me print when I ask it to, regardless of the temps it is reading from the hotend and bed thermistors through the Rambo?

Is it best to go to pins and disable the pins themselves with a -1.

Or is it best to go into the config.h and change the temp sensor failure numbers to be at points that can never be reached even without thermistors plugged into the rambo?

I obviously can just use the "has heated bed = false" for the bed, the extruder is not as obvious to me.

I am doing this due to my Rambo simply not responding to me anymore after trying to reconnect to it in the morning. Ran great last night not a hiccup in the world and now the bootloader is invalid and will not respond at all to anything.

The compartmentalized subsystems also are simply good for my piece of mind at this point due to the Rambo's none modular arrangement.


(I have digital temp controllers with thermocouples all configured and working nicely on the subsystems, faster and more accurate the the Rambo was infact)

Re: I am making the switch to independant power and temp.

Posted: Thu May 23, 2013 1:23 am
by cambo3d
were you able to use the thermocouple that came with the pid controller on the hotend? how did you attach the thermocouple to the heat bed?

Re: I am making the switch to independant power and temp.

Posted: Thu May 23, 2013 5:59 am
by Flateric
The thermocouple very luckily comes with M6 threads. The holes in the stock hotend tap perfectly to M6x1 threads. Using the stock hotend allows for the thermocouple in one side and your heater cart in the other.

For none stock hotends, of which I have more than a few kicking around here. I tap M6x1 threads about a quarter of the way through the heater carts hole. Mount up the heater cart, then thread the thermocouple into the opposite end. This gives really really accurate temps of nearly the exact point of heat transfer from the heater cart to the barrel feeding the filament. The thermo couple is good for the ranges of -50c to 900c so a very wide range that is more than you will ever need. The aluminium heater block will melt down long before you reach the peak temp. And if your over 700c and trying to print you are way off, lol.

The heated bed was a fair bit trickier to rig up. I ended up using a flat threaded plate that ride on the top plate of the printers base, the one the bed gets bolted directly to. Through this threaded plate I have a brass plumbing fitting that has the exact size diameter to be tapped with M6 thread again. This can then be adjusted upward by means of the threaded plate until it is held in contact with the bottom of the Oynx. I am less happy with this arrangement but it does seem to work fairly well. Probably there is a better way top keep the M6x1 thermocouple in contact and get better temps. I can't think of one yet however.

Yes the thermocouple comes with the digital temp controller. I am starting to think Berry has the right idea with his AC heated bed through the use of a solid state relay activated by the Rambo. Power is much much cheaper to supply, creates no inside the base from power supplies working to feed the onyx and you retain the same control as you ever had with the Rambo running the show.

Thanks for the recommendations on the digital temp controllers cambo3d they worked out perfectly.

Re: I am making the switch to independant power and temp.

Posted: Sun Jun 23, 2013 1:48 pm
by Eaglezsoar
Flateric, which digital temperature controller did you end up using?