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Job or Abort when "Adjust Stepper Driver Current Alarms"

Discussion in 'CAM' started by MonkeyNutts, Jul 24, 2021.

?

Has you Y stepper alarmed and cause the same issue for you?

  1. Yes

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  2. No

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  1. MonkeyNutts

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    Hi All,

    An interesting one for you, how many of you have had "stepper motor current alarms" which have ruined jobs or damaged your machine, yesterday I was running a slab flatten, working on a lovely slab of beach rescued oak. Managed to flatten one side then turned over and started the other. 250mm x 450mm x 50mm.

    Part way through the second side I had what I thought was a catastrophic failure, SEE ATTACHED IMAGE, my right side stepper failed, but my left kept running throwing my X gantry out by approx 150mm left to right.

    I've also had a couple of other stepper failures see post link;
    blackbox z axis issues

    The big question I'm asking here is, can openbuilds in the event of such alarms, pause or even abort the job to prevent jobs from running bad in event of Z issues and prevent expensive damage to machine structure itself!! I'm sure there are many forum members and non forum members that have had these alarms and yet jobs continue.

    [​IMG]
    I plead with the "Software Gods" to come up with a much needed solution to save our "babies" from such events. Can a function be build it to automatically pause/abort as a standard setting.?

    Is there a software view that shows what each current is set at?

    Is there any way these adjustment knobs/dials could turn by themselves over time?

    Should they be inspected on a regular basis to ensure no movement has happened, if so a software view of each current would be a really easy way to run a check! ( I had my machines for 4 months now and all of my issues have arisen in last month or so, just weird how it ran fine for months then when it start to heat up during summer months the issues arise )

    IMG_5498.jpeg

    I've been very lucky with this event, my gantry sides are 5mm carbon fibre and flexed beautifully, if they had been aluminium or metal, it would have been a different story! My machine for now appears to back up and running, but I don't know what damaged has or may have been caused by this event.

    Thank you in advance, I hope you found this thread interesting and of value to the community.
     
  2. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Long story short, no it cannot. But...

    It shouldn't happen. At least not often enough. One should commision a new machine safely. Thereafter it should be reliable

    I notice 3rd party motors in the photo. Perhaps underpowered enough or incorrect Inductance requiring you to turn the current up so high that overheating is a risk? Our motors are spec'ed to be a perfect match for the default factory adjustment on 90% of use cases. A little up for High Torques, down for NEMA17s.

    Check your motor specs, if its different to ours, we found your root cause, and addressing that, avoids the need for the fix you requested.

    Also keep in mind the Fault comes on for:
    - Stepper driver overheat
    - Short circuit
    - Over Current
    - Low input voltage
    So, if its not the motors, check your PSU, Fan, and Current Adjustment
     
  3. MonkeyNutts

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    Hi Peter,

    Thank you for your time and response, I've only had 3 events in 4 months of use and I put machine through circa 100 successful jobs, and the 3 that have occurred are all recent, in last month or so. Twice on Z and once on Y2. So sort of feel that percentage of failure on a hardware front is expected working in the software and hardware industry myself, hence asking if an alert from one part of the controller interface can send a message to another part and stop machine safely.

    Are you saying that this safety feature I asked about/suggested just isn't possible or would warrant too much development/programming work? I work for the largest UK DIY firm in Europe and we have to interface different software systems developed 10-15 years apart in some cases to get them to talk to each other, so in my simple mind, thinking that one part of a system controller can talk to another seems feasible. You guys already have what I believe to be the industry leading interface for our category, an extra level of safety can only go towards empowering that!

    The black box is situated on the underside of the spoil board, so out of way of any external interference, but do wonder if airflow/heat could attribute in this hot weather so will look to raise machine about worktable to provide a much better airflow.

    I take on board and thank you for your comments and will see if any con attribute to a more permanent fix.

    Regards
    Chris
     
  4. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    Not possible. Grbl does not read driver chip status and no hardware support for that either (status led is just connected to the LED)
     
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  5. David the swarfer

    David the swarfer OpenBuilds Team
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    maybe this is another nudge in the direction of Blackbox V2 using a 32bit chip and the new GRBL HAL so it can read driver status pins?
    Since OB is a GRBL sponsor maybe we can ask Sonny what the future holds?
     
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  6. JustinTime

    JustinTime Journeyman
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    And then Control will be updated too? Can't wait. I have a Teensy 4.1 waiting impatiently! :D
     
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  7. MonkeyNutts

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    Hi David,

    I don't know enough about CNC yet, still such a virgin at it all, but coming from a software project management background and a passion for this and making things, this is a no brainier in my eyes. As a user of a £2000+ custom machine, and potentially working on expensive jobs, which Im' sure most of your more proficient users do, you only have to have this happen once to potentially render a machine useless, as per my previous comments, I'm lucky to have carbon fibre gantry sides which flexed unbelievably! Y2 failed on me again today and this time I identified the alarm on black-box, so tuned the power down in a hope this fixes the issue, assuming its power related, to match Y2, though I have to say the grub screw interface isn't particularly users friendly, maybe a software variant to tune power on drivers can be a thing the future!. It is weird because, this is first time since purchase of machine for Y's to fail in quick succession and do wonder if the heat is playing a part? Not heat of steppers but weather temperature, added to temp of controller etc. This time I've taken an image of the grub screw positions as a reference.

    Any how, back to my point, 1 catastrophic fail could cost users significantly in repairs and loss of work, @Peter Van Der Walt said "it shouldn't happen, at least not often enough" how much does that once have to cost in lost work or repairs to warrant what I would suggest is a basic safety function (in my opinion, no disrespect to anyone), allowing a machine to continue to function in such an event could cause a fire, accident or something else if the machine were left un-attended ( I know you shouldn't leave machine un-attended, but people do) imagine if car manufacturers allow part of a car to continue operating when a key element of said car fails....??

    Do any other hobbyist CNC manufacturers have this function? If not, then you, OB have a chance to be industry leaders providing even greater reliablity!

    I look forwards to seeing if this possible new function comes of anything!

    regards
    Chris
     
    #7 MonkeyNutts, Jul 26, 2021
    Last edited: Jul 26, 2021
  8. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    A stepper driver entering error mode is probably 999th down the list of other possible failures that you can encounter while running a job (; - breaking bits, lifting a clamp, gcode errors, EMI, serial corruption and many many more happen far more frequently.

    You cannot automate your way around everything


    Exactly: Don't catch on fire (: - also known as "what happens when you leave CNC unattended" [pics]

    Climate change? Summer now there right?
    or, accumulation of dust, fan starting to fail?
     
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  9. MonkeyNutts

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    Like I said, I'm a real virgin at this, even after several months, you've probably heard what I'm saying for the 100th time already..... ;-)
     
  10. David the swarfer

    David the swarfer OpenBuilds Team
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    So this failure is new, therefore there is a cause!
    Mid summer ambient temperatures are an immediate alert. To improve the cooling on the blackbox, open it and blow all the dust out, clean the fan blades etc (observe proper static prevention!). When you turn it on, make sure the fan is running full speed. Fan bearings get old quite quickly if they run hot, visible as slow starting from cold and speeding up over the next few minutes.

    I would also point a desk fan in the general direction of the BB from about 4 feet away.
    I live in Africa, and a summers day can hit 35C in my craft room, which happens to be the coldest room in the house. I always have a fan blowing on the laptop and drivers under these conditions. (my system is an arduino Uno with external DQ542 drivers)

    All good points but you have missed a fundamental design factor in the BB, it is designed for hobby machines for hobbiest users, simple and easy to use, easy to connect, very little configuration.
    The side effect is that there are 'industrial' things missing, and error checking the drivers is one of them.
    There is certainly a market for an advanced controller.
     
  11. David the swarfer

    David the swarfer OpenBuilds Team
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    Have to disagree (-:
    My first job was in embedded automation, and our policy was "you can control it if you can measure it". (and getting realtime performance out of a 386 16Mhz MSDOS platform involved a fair bit of assembly code and performance tuning)

    Modern CNC machines bristle with sensors, you only have to watch some of Peter Stantons videos to see that his Integrex has a sensor for everything and will stop the machine if anything fails a test. Of course this includes motor drivers, but also includes the chiller fan and everything else that moves, or is not supposed to move (-:

    My son-in-law programs Kuka robots, and they have a sensor for everything, and error reporting for everything that is sensed, and most often work in concert with one or more PLC's that are sensing everything that the robot is not directly connected to as part of the cell or production line that forms the entire system.

    BTW a PSA for everyone, if you are not watching CNC Youtube channels like Edge Precision, Grimsmo Knives, NYCCNC and so on, then you are missing out on a vast body of knowledge that is offered to you for the cost of watching a video. Much more useful than reruns of Lost or Game of Thrones! No you probably won't own an Integrex, nor run a Kern, but you CAN learn to 'think CNC' better, faster, safer, in a much shorter time than it would take you to make all the mistakes yourself. (-:

    How do you know the chiller has a problem? There is a sensor for that! (-:
    https://www.youtube.com/channel/UCe0IyK4ntgdPTTjsxjvyHPg
     
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  12. Peter Van Der Walt

    Peter Van Der Walt OpenBuilds Team
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    OK OK :) - rephrasing:


    You cannot automate your way around every possible point of failure, without endless budget and time constraints, but we certainly did cover the popular fail cases already (;
     
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