1. Got a question or need help troubleshooting? Post to the troubleshooting forum or Search the forums!

Turn Version 1 Bed Heater into a Version 2 Bed Heater

Discussion in 'Mods and Upgrades' started by WheresWaldo, Jan 11, 2018.

  1. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    Since I had my bed replaced with a version 2 I had the original bed to play around with. Since the version 2 bed requires the removal of the Pogo Adapter, that was no longer in the way. The biggest obstacle was finding the appropriate connector to make an adapter cable to connect the old bed to the wiring harness. What I found was that the connector used was a Chinese clone of the AMP TE 5-103945-7, which is a crimp male socket for the wiring harness connector. The connector is wired as follows (from left to right looking down at the keyway)"

    1. Thermistor
    2. Thermistor
    3. Bed +
    4. Bed +
    5. Bed +
    6. Bed -
    7. Bed -
    8. Bed -
    A bit of heatshrink and Kapton tape and now I have a working version 2 bed.

    20180111_124610[1].jpg

    20180111_124553[1].jpg
     
    mark tomlinson likes this.
  2. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    I should note that both the bed and the thermistor are purely resistive loads so you do not have to worry about which side is positive and which side is negative when you attach the cable.

    The AMP connector is rather small and will only accept wiring up to 20 AWG. That is why the heater is wired with three wires per side, The Robo wiring harness also uses 20 AWG wiring.
     
    Shrey likes this.
  3. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    The white sheet is PEI but I would not recommend using it. So far in my testing the trigger distance is increased is between 15 - 20 mm from the bed. Of course you can handle that with Home Offsets but I also tested the repeatability of the probe with the white sheet and what I am seeing is a range of trigger points that is almost on the verge of unacceptable. I ran the command M48 P10 several times to that I could get a range of 10 measurements. All measurements were taken at the same location on the bed and at the same ambient lighting conditions to reduce any variables. Here are the results:

    Run 1 - Mean: -0.379250, Min: -0.536, Max: -0.291, Range: 0.245, Standard Deviation: 0.068309
    Run 2 - Mean: -0.406325, Min: -0.503, Max: -0.291, Range: 0.212, Standard Deviation: 0.071752
    Run 3 - Mean: -0.389225, Min: -0.522, Max: -0.244, Range: 0.278, Standard Deviation: 0.087773​

    What is disturbing is the range that the probe finds acceptable. I will retest with the standard Robo bed and provide those results as well.
     
    #3 WheresWaldo, Jan 11, 2018
    Last edited: Jan 20, 2018
  4. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    Just for a point of reference, I performed the same test on the Robo BuildTak sheet used in bed version 2. Here are the results using the same command, and probing in the same location:

    Run 1 - Mean: -0.038700, Min: -0.090, Max: 0.028, Range: 0.118, Standard Deviation: 0.035226
    Run 2 - Mean: -0.070875, Min: -0.104, Max: -0.022, Range: 0.082, Standard Deviation: 0.027702
    Run 3 - Mean: -0.055000, Min: -0.099, Max: -0.014, Range: 0.085, Standard Deviation: 0.023808​

    Of course this is just one data point, but it is apparent to me that using the black sheet not only lowers the trigger distance but also makes it more repeatable.
     
  5. JeffreyB

    JeffreyB Member

    Joined:
    Mar 25, 2016
    Messages:
    67
    Likes Received:
    29
    Did you see this? Are they actively working on the IR's lack of accuracy due to varying ambient lighting? https://github.com/Robo3D/Marlin/blob/DAC_Edit/README.md

    • Added G35 command. Auto adjust Probe Offset(M851 Z) for ambient light levels based on the trigger distance of the IR probe(Requires Home Offset Z(M206 Z) to be set)"
     
  6. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    Yes I saw it and it is not a solution. All that code does is force resetting the home offset for every print if you use that particular non-standard g-code in your start up. It doesn't actually address the inconsistency in the probe.

    Please do not get me started on the code Robo produces. So far as long as I have watched their GITHUB they have not produced a single line of code that actually improves print quality or printer speed. They tend to ignore bugs in their code. They have no real means of accepting feedback or bug reports.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    19,133
    Likes Received:
    6,347
    The correct way of doing this would be for them to become actual contributors to the Marlin code and adding fixes/improvements to the main Marlin code-line. Forking your own path is certainly one approach, but does nothing to improve the actual main code (which presumably you would want to consume later for further improvements/fixes)
     
  8. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    I have no issues with forking the code, but if you are going to add whole new sections of code, you should at least make sure it does something good. Just doing no bad is not enough.
     
    Geof likes this.
  9. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
    Staff Member

    Joined:
    Feb 21, 2013
    Messages:
    19,133
    Likes Received:
    6,347
    Well, that would be a start ;)
     
    Geof likes this.
  10. AllenMcAfee

    AllenMcAfee Moderator
    Staff Member

    Joined:
    Jan 4, 2016
    Messages:
    13
    Likes Received:
    13
    Hello everyone. I'm reviewing the modifications that Waldo has been posting and want to explain a couple of the points that have been raised in this post.

    G35
    The strategy around G35 is to indeed compensate for changes in ambient light levels, and how they effect the trigger distance. We switched from the Z Probe offset method early in production to the Home Offset method due to this issue. Since then we have used the IR probe only as a leveling tool, rather than allow it to dictate offset distances. With G35 we are setting the Z Probe offset (M851) at the start of every print based on the Home offset (M206) that is stored. In internal testing we are having very good repeatability of the first layer, so long as the Home Offset is correct. G35 does not change the Home Offset, however, since the only command being applied at the end of the routine is M851. With this schema we now use M206 and M851 together.

    Probe repeatability
    The white surface material and the repeatability of the probe is another matter, and one that G35 does not directly handle (as Waldo mentions). It comes down to the ability of the material color to absorb infrared light. The reflectance of black materials is obviously lower than white materials, so it allows a smaller Distance to Spot ratio and thus a more repeatable distance for the intensity the IR sensor is programmed to recognize.

    Since the trigger distance of the white material is much greater than the black material, the reflected spot on white surfaces covers far more bed area than we'd like, throwing off the repeatability of the probe. If you find the current repeatability of the probe to be an issue, I'm looking for feedback. Bottom line is that white materials are simply too reflective for the probe, so sticking with darker colors (preferably black) will give us better results.

    Contributing to Marlin
    As of right now we are still in testing and debugging of the next firmware release for RoboOS 2.0. 1.1.8 has raised quite a few issues that we are just about wrapping up. The only major changes we've made to the source are dealing with what we've described above. The changes made since we forked the RC branch at the end of October will be pushed onto the Marlin team once we've passed our test patterns (both internal and external). As far as I know, no one is working on IR probing fixes to the Marlin project, so we do want to contribute these as thinkyhead sees fit.

    Again, we're always looking for feedback, even if it has been difficult to do so in the past. Our Marlin repo has the issues list open to the public, so feel free to post your thoughts. As small as our team is I do not have much free time to browse the forums, so I do miss most of the conversation that happens here. I will try to carve out more time in the coming year. I hope this helps.
     
  11. Redriche

    Redriche Member

    Joined:
    Jun 7, 2017
    Messages:
    64
    Likes Received:
    15
    So do you have a link to the connector?


    Sent from my iPhone using Tapatalk
     
  12. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    Redriche likes this.
  13. Hellsbells17

    Hellsbells17 Member

    Joined:
    Aug 10, 2017
    Messages:
    38
    Likes Received:
    5
    I must be lacking behind. What is the version 2 bed heater?
     
  14. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
  15. Hellsbells17

    Hellsbells17 Member

    Joined:
    Aug 10, 2017
    Messages:
    38
    Likes Received:
    5
    So the bed is not removable?
     
  16. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    No they added a direct to bed soldered socket, the wiring harness remains the same.
     
  17. Hellsbells17

    Hellsbells17 Member

    Joined:
    Aug 10, 2017
    Messages:
    38
    Likes Received:
    5
    Is there something wrong with Version 1?
     
  18. WheresWaldo

    WheresWaldo Volunteer ( ͠° ͟ʖ ͡°)
    Staff Member

    Joined:
    Feb 18, 2015
    Messages:
    5,200
    Likes Received:
    3,167
    For some people the pogo pin springs fail.
     

Share This Page