Min max switches enable

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Yes they are for homing, I think the follow up question from @makerjace was how accurate are they? The reason for this question is many people want to be able to home the machine and precisely return to a work offset position to resume a project after a power off or e-stop. For this to work you need precise homing that is repeatable so when you return to the previous absolute offset as your work offset point you can pick up where you left off.

The Masso documentation states their optical sensors are 10 micron accuracy. I’ve tested inductive limit switches on my OF and have seen 2 micron or better accuracy. I’ve not tested a microswitch for homing accuracy and repeatability but I’d wager they’re not going to be as precise. Would be nice to get some hard data on them.

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Thanks for summarizing this! You hit the nail on the head.

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I would add that some, like myself, require it to be accurate and repeatable for locating tool holders when running an ATC setup. Also, if using a Masso controller’s jump to line feature after recovering from a shut down, a repeatable homing sequence becomes important as well.

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Hey Michael,

I am glad that the microswitches have been running error-free for so long on your machine.

One possible cause for our different experiences could be the humidity. It is true that I had my coffee grinder and my spice grinder in a very humid kitchen (>70% r.H.) for a while before I changed that, whereas you may have a workshop with ideal humidity (30%–50% r.H.).

But one thing is for sure: A point in time, at which a failure of the switches is to be expected, exists only with microswitches. With inductive, capacitive, reed or magnetic (hall effect) switches, there is no such thing, ever. And with photoelectric switches, just be aware of dust and debris.

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Hey Derek,

true for inductive sensors, but in this case reed switches with magnets would be ideal for being connected directly with no external circuitry/voltage, and avoid the disadvantages of microswitches.

Reed switch: Life

That belongs to the Onefinity Original Series concept, make sure low entry price by saving on everything. Although it’s rather inherited from buildbotics.com in this case.

Anyway I just have found a nice aluminium case attached with a nice D-sub cable to build a better breakout box with optocouplers :slight_smile: to the Original buildbotics-derived Controller

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Question about the way a limit switch affects the stepper motor. With my X50 WW now hung on it’s QCW frame, I’m having nothing but problems with the X axis dropping to the bottom of the Y rails any time it bumps the brackets at the upper limit. Stall homing apparently disables the holding force of the Y stepper motors. It also happens when I’m using the touch probe. Z and X set with no problem, but the Y motors release their hold upon first bump of the probe. It’s unnerving.
I’ll soon have my upgraded 1.9Nm braking motors installed, and I’m hoping the improved holding torque will solve this problem, but would limit switches overcome this? Or does the controller interrupt power to the stepper whenever the min or max-switch is reached?

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Hey Justin,

no, not at all, as it has nothing to do with the stepper motors. The “min-switch” and “max-switch” choices under “Homing” on each of the MOTORS pages is for hardware limit switches. It is the selection to make the machine use them. However on Onefinity’s Original X-35/X-50 Series with buildbotics-derived Controller, your machine has no such limit switches, as a stock Original Series machine relies exclusively on Stall Homing (=machine bumps the axis carriage to the end of travel until the stepper driver detects it). As long as you did not Retrofit Limit Sensors to your machine (which the buildbotics-derived Onefinity Controller supports out-of-the box through the I/O port), this selection is useless, and activating it will only try to find a hardware switch at the home position that doesn’t exist.

One good advice: There is much information already present in this forum. Please, do more clicking on the links if you encounter some, and use the search function first to find answers, before you ask a person.

In the forum’s General Forum FAQ, it says:

One way to improve the discussion is by discovering ones that are already happening. Spend time browsing the topics here before replying or starting your own, and you’ll have a better chance of meeting others who share your interests.

However your question in How to Wire a Stepper Motor Brake (Back to Wall Mounting) was not yet answered in this forum, as far as I understand this thread. I will be glad to provide you an answer and a solution when I can.

OT: A message from the author of this post

:face_with_thermometer: :syringe: :pill:
:medical_symbol: :hospital: :stethoscope:
:drop_of_blood: :person_in_lotus_position:

OT: Please excuse me for not having been able to continue writing in the forum, and for a moment I will be less able to do so, at least only to a reduced extent, and at least at the moment unfortunately not on topics where I have to work in my electronics workshop to implement or experiment the topic. I’m currently facing serious health issues that have the potential to knock me out completely (not cancer, but serous illness. Will be fine again though, I believe).

I plan to develop a proper solution for Retrofitting and Wire Stepper Motors with Brakes for both platforms, the buildbotics-derived Original Series as well as the Elite Series, and describe it on the forum, just as I’m working on a better, wired breakout box for the buildbotics-derived Original Series, with optocouplers (protecting the AVR), circular proximity sensor limit connectors, etc… But all this is not going to happen at the moment.

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Hey Justin,

are you doing stall homing against gravity? This will not work. This was already a topic in the forum. Please use the search function.

You got to reverse the Y axis under “Motion” on the MOTOR 1 page so that home is on lower left. This way stall homing will be done on the lower end, which will allow stall homing to cope with the mass. You should also reverse X axis so that home is on the left and your workpiece does not result in being mirrored.

Also you can adjust the motors settings in general if you use vertical wall mount, use forum search function.

yes, that’s exactly what it does, because stepper driver needs a moment with no current to sense the missing electromotive force to detect stalling. This is explained under one of the links above. This is by intention. Therefore, you can’t do stall homing against gravity on vertical mounting. You got to reverse the axes on the MOTORS pages. Please use search function, this was already discussed in this forum.

As mentioned above, there exists a video to adjust the general motors settings. You got to make use of altering these settings if you mount the machine vertically (wall mount).

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Thanks again for your sage advice. I do research fairly thoroughly before I ask for help, but don’t come across everything that’s out there, so appreciate the references. The rabbit holes are endless, but I’ll find them all eventually…
Sorry to hear you’re dealing with serious health issues. I wish you a quick and thorough resolution. Exactly the reason I got involved in CNC two years ago. Did a week of soul searching and research while awaiting surgery for my condition, and ordered my X50 during recovery.

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I 3d printed them.