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Confused

Discussion in 'General Questions' started by Lance Weston, Mar 22, 2019.

  1. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    It will seem like a bit of extra work on the R2/C2 because you either hook a monitor up to the pi and download the arduino compiler on the pi and run/edit the firmware there and load it on the board OR you disconnect the pi and run straight from a PC to the controller board to reload the firmware. I just took the first option and ran VNC on the C2 RaspberryPi and then opened a VNC session from my PC to run everything on the Pi,. Left it there so if I needed to do it again, everything is still staged there.
     
  2. Lance Weston

    Lance Weston Member

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    I ordered a Zyltech Ramps Arduino combo for $25. The Robo board uses 24v to the steppers. On the Zyltech this would not let me PWM the fans at 12v unless I add a separate 12v supply and modify the board to accept the 12v. Will the existing steppers would work off of 12v. Since the steppers are current driven I suspect they would. Does anyone know for sure? For the bed I have no choice, I must drive with 24v. I ordered a couple of FET switches for $1.50 each. If I run at 12v I can take the 12v output and drive the switch giving 24v output to the bed. I can do the same for the extruder or put in a 12 heater. I got the version of Arduino 1.06 that Zyltech recommends. My assumption is the Marlin firmware gets downloaded and I have to use the Robo configuration.h. I do not have the Robo Configuration.h.

    This all looks pretty straight forward hardware wise if the steppers work on 12v. I am unsure of what firmware/configuration file to load.

    As the project continues I will keep you up to date.
     
  3. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    All stepper drivers are designed to work 12 - 24V, 24V is easier on the Stepper Motors, but not a real big concern. Robo3D has their own GITHUB repository for Marlin, they are currently using 1.1.6 there are two community threads with 1.1.9 an 2.0.x Bugfix.
     
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  4. Lance Weston

    Lance Weston Member

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    Thanks, I will chase down the github. I found the schematic of the Ramps board and the the Ramps output is a FET switching to GND. If I connect one side of bed and extruder plus to the 24v supply and the other side to minus there should be no problem. It will back bias the led 12v, but I sold millions of boards that had leds spec of 5v back bias running at 12v with no problem. I can use a cheap 5 amp 24v->12v step down regulator to power the boards. I use 3 30mm fans drawing 100ma at 100% and the main fan is 12v @ 200ma, led strip 100ma?. I doubt there is more than an 200 ma at 12v for the electronics. The Steppers draw an amp each?

    I purchased a separate 12v supply just in case.

    So now everything is defined, it is just a matter of doing. Will be a month before all of the parts come in from China.
     
  5. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The steppers can draw as much as 3 amps if you tune them that high (1-1.5 amp/phase, two phases A/B)
     
  6. Lance Weston

    Lance Weston Member

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    Okay, I may need the separate supply, or dummy up the interface board to deliver 24v to the steppers and use the stepdown regulator for the rest. This is where I think the different firmware resides. Octoprint and all of it 's apps on the Rasberry Pi. The interpreter of the G commands and the interface functions on the Aduino board. I found the Robo hex file 1.2.4 and pasted the hex to notepad. When I down load that hex file to the Aduino board I should be identical to the Robo custom board except for 24v steppers. Is this correct?
     
  7. WheresWaldo

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    Provided Robo didn't change pin assignments on their proprietary board. it should work. Robo's mainboard is RAMPS compatible but may not be a 100% clone.
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    If you get a different board you can't use the hex file. You need to use the Marlin source, configure it for your board -- and that custom board or the Arduino OR whatever board you use THAT is where the firmware resides :)
    If you just customize their custom board to use 24v steppers (a neat trick, but doable) then you could probably use their firmware IF the steppers are the same steps/mm as the stock ones (IIRC the Robo ones are 200 steps/revolution)
     
  9. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
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    Robo uses 1.8° Steppers (200 full steps per rotation) and their mainboard uses A4988 Stepper drivers with 1/16 microstepping enabled,
     
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  10. Lance Weston

    Lance Weston Member

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    Okay, good if they did not reassign pins. If they did then I load the Marlin software then set up the configuration.h to define the IO . The Octoprint and all of it's apps is in the Rasberry Pi so operation should be identical. I realized that I will need a touchscreen to test on the bench. The ones I looked at had an HDMI connector and a mini USB. What is the ribbon cable on the Robo for?
     
  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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  12. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    On the C2 that has video and touchscreen on the R2 probably just touchscreen
     
  13. WheresWaldo

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    The ribbon from the mainboard goes to the upper board and included Thermistor, Hotend heater, fans, etc.

    The Ribbon from the rPi is for the touchscreen.

    I totally forgot about the rPi ribbon as I am not using one. It was eliminated when I did the upgrade to the capactive touchscreen.
     
  14. Lance Weston

    Lance Weston Member

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    I found this schematic and will buzz out the board when I get it to verify. This PDF schematic for the ramps board shows that you can select the voltage for the bed and motors separately. The fans are 12v. The PNG schematic shows that the voltages are common. Would love to get the zlytech schematic
     

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  15. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yep, unlike their custom one you can do a lot more options with the other boards.
     
  16. Lance Weston

    Lance Weston Member

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    You called it. Robo uses two CPU's and the few pinouts I traced on the mega 2650 are different on both boards. I will have to load the Marlin firmware and let the rasberry Pi talk to it via G code. At least that is what I think the system does.
     
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  17. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    Yes, that is exactly how it works.
     
  18. WheresWaldo

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    It really isn't very complicated just tedious, busy work. Pretty much all FDM 3D printers work the exact same way electronically. You have a mainboard with a CPU and either it is combined with electronics for sensors and motor drivers or there is a separate daughter card that provides that function. The Robo just combined everything. the basic connections are 4 wires to each stepper, 2 wires for the bed heater, 2 wires for the hotend heater, 3 wires to each endstop (there are 3, one for each axis), two wires to each temperature sensor, two wires for power input.

    In the Robo they added an rPi to help control everything and it is hooked up via USB cable. even if you replace the mainboard, there should be no need to touch anything on the rPi. It just runs OctoPrint and their own code for the screen interface. https://octoprint.org/, specifically they have loaded this distribution of OctoPrint, https://github.com/guysoft/OctoPi. Their interface plugin, controlling the TFT screen and skin of OctoPrint was written to an old standard for OctoPrint and has never been updated so you cannot upgrade OctoPrint to a newer version. Basically just leave the rPi alone and you should be good no matter what board is behind the actual printer control.

    Now if you look at Robo's GITHUB, https://github.com/Robo3D/Marlin, which holds their current version of Marlin for the R2/C2 printers is based on Marlin 1.1.6. The made some stupid changes to Marlin to accomodate some really dumb ideas a wayward former user/employee convinced them was better, and added it to base Marlin code, on Feb 22 they edited Marlin 1.1.9 to see what they could retrofit into it and to see if it would work with their funky code additions. That is all you should care about. You need to compare the source between Robo's version of 1.1.9, https://github.com/Robo3D/Marlin/tree/1.1.9-dev, to Marlin's default configuration for the same version, https://github.com/MarlinFirmware/Marlin/tree/bugfix-1.1.x. Some things will stand out as different, such as endstops used, PID numbers, sizes, location of homing, etc. You will also see a motherboard difference as Robo added pins_ROBOMB.h and default Marlin is preconfigured to use pins_RAMPS.h, you will need to compare them to see if they match or at the very least match your new wiring.

    There is more steps, but that is the basic outline of what needs to be done to do a heart transplant from one to another.
     
    #38 WheresWaldo, Mar 24, 2019
    Last edited: Mar 24, 2019
  19. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    +1
     
  20. Lance Weston

    Lance Weston Member

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    Thanks for all of the info, but now I am confused again. Thought I understood but apparently not. I thought if I loaded the Marlin I would not have to deal with the Robo addresses. I thought the Marlin code would take care of all of the addresses on the Ramps/Arduino. I thought only Gcode traveled from the Pi to the Ramps/Aduino.

    I think I have figured out how to repair the Custom Robo board. There are only three signal lines that matter on the stepper controller chip. I am in the process of cutting the three traces on the E1 stepper controller and jumpering the lines to the X stepper controller. I will use my favorite engineering term and say that it "should" work by then moving the stepper cable to E1.
     

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