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Using Arduino board on Robo R2 project in process

Discussion in 'Mods and Upgrades' started by Lance Weston, Mar 27, 2019.

  1. tkoco

    tkoco Administrator
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    I looked at the diagram and have one question: Why would the thermistor for the print bed be routed through the downtown board at the bottom of the extruder? (Reference the bottom right corner of the diagram) Or am I misunderstanding the situation?
     
  2. robert trama

    robert trama New Member

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    i think that is the spare port for the second hotend extruder
     
  3. tkoco

    tkoco Administrator
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    Makes sense now that you have pointed out the situation. Second hotend thermistor to pin 13 and then on the main board end, to the "unused" point (indicated at the top of the diagram).
     
  4. Lance Weston

    Lance Weston Active Member

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    The two thermistors on the connector on the lower right are for the two hotends. At the top of the schematic you can see the thermistor for the bed. If you use the existing downtown board which has the thermistor grounded you will not get good temp regulation, but it will work. Partsbuilt.com supplies a modified downtown board having a jumper to isolate the ground on the hotend thermistor one, bringing it to the hot on hotend two. The result is that you use the two thermistor lines as both ends of thermistor one. This will give you much better temp regulation. The ramps board prefers an isolated thermistor. I have used the Partsbuilt board and it works great. I have also removed the hotend one connector from the downtown board, used a diamond bit in a dremmel to isolate the gnd, then reinstalled the cconnector and jumped the now isolated ground to the hot on thermistor two. This also works. I bought the Partsbuilt boards because it is easier and looks better.
     
  5. Lance Weston

    Lance Weston Active Member

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    you can still make things work without isolating the gnd end of thermistor one. Just be careful, in that the the connector on the ramps would now be polarized. Gnd to Gnd and hot to hot. Reverse this and the you would be grounding the hot and get a crazy reading on the LCD
     
  6. robert trama

    robert trama New Member

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    i am having trouble finding a 15 amp fuse holder that would fit where the 5 amp ptc fuse was. any suggestions as to where i can pick one up?
     
  7. Lance Weston

    Lance Weston Active Member

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    these are what I purchased. All required some dremel work and then fit
     

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