Spindle self rotates on start up!

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gMike
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Spindle self rotates on start up!

Post by gMike »

Hi All,

When booting Acorn my spindle rotates without being commanded, this seems pretty dangerous and the motion occurs before the 9033 reset is cleared.

To replicate
1 - PWM spindle mode
2 - Powered acorn off then back on while in centroid
3 - Restart centroid

Outcome
1 - Software starts booting
2 - Spindle turns very rapidly for perhaps 5 revolutions and stops
3 - Software finishes loading normally with the normal 9033 reset message appearing.

I just smashed a beautiful mitutoyo dial indicator into my z-way which was in-turn damaged. My spindle motor (teknic MCVC-2346d) has an enable wire, it shouldn't be impossible for the spindle to move prior to the 9033 reset being cleared.

What on earth have I missed? This seems like a dangerous software bug though I fully admit it could be my own stup1d fault : )

Cheers...Mick
Last edited by gMike on Sat Jun 11, 2022 8:05 pm, edited 1 time in total.
gMike
Posts: 23
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Re: Spindle self rotates on start up!

Post by gMike »

Update,

The no-fault-out relay is busy powering the CNC4PC clearpath breakout board (and not the spindle enable). The surge of unexplained PWM signal remains a mystery.

I'd like to request a really simple enhancement
When you drag outputs from the list in the wizard they disappear meaning you can't duplicate them. This is usually fine until you have two different devices that need the same signal. Is it possible to change the wizard so items don't disappear from the selection list when they have been used?

My fault in the end but I didn't see the random PWM signal coming.

Thanks...mk
gMike
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Re: Spindle self rotates on start up!

Post by gMike »

Update,

There seems to be no other other output that resembles the no-fault-out signal enough to be used to safety enable the spindle motor. My choices

1 - Continue to allow my spindle to randomly move (Yikes)
2 - Remove all fault conditioning from my spindle motor (Yikes)
3 - Risk damaging all my electronic my piggybacking the CNC4pc C86ACCP board no-fault enable to the spindle enable (Yikes)

The more I have looked at this problem the more I believe there is no safe solution. The problem is the random blast of PWM signal when centroid loads.

Perhaps another software solution is that no PWM signal can be generated while the board is in fault mode (My original assumption!). I know the PWM signal is a new feature so can someone from centroid please have a look at this, I think it is a real safety issue, scared the heck outta me.

Unfortunately my z-way (column bed) is damaged beyond repair so my mill is now down for 6 weeks awaiting parts. My Mitutoyo dial indicator is now a pretty pile of ruby's : (

If you have any suggestions please sing out.

Many thanks...mk
gMike
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Re: Spindle self rotates on start up!

Post by gMike »

Minor Update

Did some testing and the spindle will still move with the probe plugged in. (No commands given!)

Cheers...mk
tblough
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Re: Spindle self rotates on start up!

Post by tblough »

You cannot have multiple outputs on the Acorn powered by one signal. That is why the signal name disappears from the list when used. The solution to this is to use the no-fault-out relay on the Acorn to control an external relay that has multiple contacts.
Cheers,

Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
Gary Campbell
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Re: Spindle self rotates on start up!

Post by Gary Campbell »

gMike wrote: Sun May 15, 2022 12:41 am Hi All,

When booting Acorn my spindle rotates without being commanded, this seems pretty dangerous and the motion occurs before the 9033 reset is cleared.

To replicate
1 - PWM spindle mode
2 - Powered acorn off then back on while in centroid
3 - Restart centroid

Outcome
1 - Software starts booting
2 - Spindle turns very rapidly for perhaps 5 revolutions and stops
3 - Software finishes loading normally with the normal 9033 reset message appearing.

I just smashed a beautiful mitutoyo dial indicator into my z-way which was in-turn damaged. My spindle motor (teknic MCVC-2346d) has an enable wire, it should be impossible for the spindle to move prior to the 9033 reset being cleared.

What on earth have I missed? This seems like a dangerous software bug though I fully admit it could be my own stup1d fault : )

Cheers...Mick
Nope, you have something connected improperly and may have misunderstood the intended use for the output designations.
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ShawnM
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Re: Spindle self rotates on start up!

Post by ShawnM »

gMike wrote: Sun May 15, 2022 12:41 am
What on earth have I missed? This seems like a dangerous software bug though I fully admit it could be my own stup1d fault : )

Cheers...Mick
Given the choice between your options of a "software bug" or "it could be my own stupid fault" and if I were a betting man I would bet it's NOT a software bug. Just sayin' :mrgreen:

As suggested triple check your wiring because something is not right and utilize the "no fault out" to drive a contactor or even multiple contactors to power up components when everything else in in order.

Give us some more details of your system and a copy of your report and we can help.
Last edited by ShawnM on Sun May 15, 2022 11:13 pm, edited 1 time in total.
Gary Campbell
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Re: Spindle self rotates on start up!

Post by Gary Campbell »

No one will be able to do any more than venture a wild ass guess until you post a report, list your components and provide a drawing of how you have them connected.
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gMike
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Re: Spindle self rotates on start up!

Post by gMike »

I have thought a lot about the comments above and for the most part you guys are very correct.

There is however one comment I'd make that I think is fair and square. Acorn should not be generating thousands pulses of its own accord during start up. This point is very very strong.

I am an engineering manager for a large team. The trick to genuine safety is protection in depth, ie multiple layers of defence. Relying on the enable relay as the only defence is negligent, I am responsible for the safety and welfare of many people and I don't use the word negligent lightly. I am lucky because my mill is small and the bit of metal that hit my head was light and had no chance of injury, I fear one day someone else won't be so lucky.

I feel a legitimate hazard has been reported and not acted on by centroid. Thousands of PWM pulses randomly being created on any controller is simply dangerous. I wound up following tblough's suggestion (thanks!) to use a separate relay to duplicate the enable command so my own troubles are fixed.

I hope centroid stay lucky and someone else doesn't end up with a more unfortunate outcome. Centroid if you're listening, I am keen to help and have multiple easy fixes.

gMike
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Re: Spindle self rotates on start up!

Post by Muzzer »

It does seem odd that you appear to be observing a behaviour nobody else has (ever?) observed.

As a senior engineer myself (engineering director / VP engineering etc) involved in safety critical systems (IEC61508, ISO26262 etc), I appreciate why you may be concerned. However, despite requests for you to post your report so that Centroid and/or the other users here can diagnose what you consider to be a critical issue, you seem unable to bring yourself to do so. If one of my engineers came to me with such an issue and failed to provide the requested data to enable an investigation, preferring to write opinion pieces instead, let's just say I'd be having a discussion with him/her about his/her position within my team.

Please post your report and details of your setup, as outlined by Gary above!! If you believe there is a hazard to be addressed, surely there is a responsibility on you to help to identify and rectify it.
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