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Re: Mach4 problems when moving.
« Reply #10 on: July 10, 2018, 06:13:20 AM »
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That the deceleration is that violent that the servo faults?
Yes, it's very fast. When the machine cuts the laser at a speed of 30 meters per minute, then there is no problem with braking. He cuts the angle of 90 degrees without problems, you can see the video above. When the CycleStop button is pressed, the deceleration speed is not taken from the Motor Tuning window, but what is the maximum possible.
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I'm interested how you think it works.
I think there should be two braking modes: with the saved position (FeedHold) and when the current exact position is not important (CycleStop).
I could be wrong.
If I press FeedHold, then I want to return to the position and continue the cut.
If I press a stop, I don't want to keep cutting. It's bad that the Match will lose its position, but if the deviation is not strong, there are no servo errors and loss of parallelism of the slave axis relative to the master, this will suit me. There should be a braking installation for the CycleStop, all machines and parameters are different.
Completely could not translate your questions.
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My misunderstanding, you are not concerned with keeping exact position? You just want to stop?

If that's the case just program your servo to some maximum deceleration. You will have to disable the following error also as there will
be an overrun that will cause a fault.
Completely could not translate your questions.
Re: Mach4 problems when moving.
« Reply #11 on: July 10, 2018, 06:19:59 AM »
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What I am proposing is that you limit your servo/drive acceleration to be just a bit more than your max tuned acceleration. Your max tuned acceleration would become the effective maximum acceleration AND deceleration.
Craig,
This is wrong (I think so ....), mach does not have feedback. For such control systems, the internal PID loop must be faster than the external one!
Re: Mach4 problems when moving.
« Reply #12 on: July 10, 2018, 06:37:32 AM »
Here is the servodriver and the engine. Reduction gear 14/1.
Re: Mach4 problems when moving.
« Reply #13 on: July 10, 2018, 06:40:53 AM »
Hi.

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I think there should be two braking modes: with the saved position (FeedHold) and when the current exact position is not important (CycleStop).
This is the same conclusion I come to. If you wish to retain exact position the <FeedHold> then <CycleStop>.  If you wish to stop with the maximum
possible deceleration obtainable with your servo then <CycleStop>

At the current time when you <CycleStop> the deceleration is so abrupt that the servo faults which is less than desirable. You do know however that it can
mange the acceleration in your motor tuning page because otherwise it would fault under acceleration as well.

I'm going to guess that you can program a maximum current in your drive which will in turn limit the acceleration. If however you turn the
current limit down eventually the servo will not be able to even accelerate as quickly as your Mach tuning. If you have the current limit just above that threshold
then your servo will accelerate at the max Mach tuning rate and should decelerate at the same.

There are three fault conditions that could be happening when you execute <CycleStop>:
1) Overcurrent....the drive is trying to decelerate so quickly that the drives current limit is exceeded
2) Overvoltage.....the servo after run is generating voltage which has to be absorbed by the drive and regen resistor if fitted. If the voltage gets too high the drive
     will fault rather than have the DC link capacitors blow up
3) Following error....under normal operating conditions we want the following error window to be small and so be assured that the servo is following its commanded
    position as closely as possible. Under <CycleStop> conditions the commanded position stops whereas the encoder runs on as the servo decelerates with an ever
    widening error and eventually the following error will be exceeded. One possibility it to set the following error window much wider so that it doesn't fault under
    <CycleStop> condition or program Mach to ignore a following error under <CycleStop> condition.

Can you post some details about your servos and drives? A manual would be great.

Craig

My wife left with my best friend...
     and I miss him!
Re: Mach4 problems when moving.
« Reply #14 on: July 10, 2018, 09:14:33 AM »
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I'm going to guess that you can program a maximum current in your drive which will in turn limit the acceleration. If however you turn the
current limit down eventually the servo will not be able to even accelerate as quickly as your Mach tuning. If you have the current limit just above that threshold
then your servo will accelerate at the max Mach tuning rate and should decelerate at the same.
The problem is that the match does not use braking, but simply cuts off the steps. I'm sure that the PID settings in the servo drive should be as high as possible, so that you can accurately perform the task of the match. On the laser cutting machine, the speed G0 is equal to the speed G1, the servomotors are tuned to the minimum possible following error. Limiting current, voltage, speed is the wrong way. When the machine performs the job, then there are no errors, everything works. Reducing the parameters in the servo will reduce the accuracy of the operation.
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There are three fault conditions that could be happening when you execute <CycleStop>:
1) Overcurrent....the drive is trying to decelerate so quickly that the drives current limit is exceeded
2) Overvoltage.....the servo after run is generating voltage which has to be absorbed by the drive and regen resistor if fitted. If the voltage gets too high the drive
     will fault rather than have the DC link capacitors blow up
3) Following error....under normal operating conditions we want the following error window to be small and so be assured that the servo is following its commanded
    position as closely as possible. Under <CycleStop> conditions the commanded position stops whereas the encoder runs on as the servo decelerates with an ever
    widening error and eventually the following error will be exceeded. One possibility it to set the following error window much wider so that it doesn't fault under
    <CycleStop> condition or program Mach to ignore a following error under <CycleStop> condition.
What a mistake on the servo - it does not matter. You eliminate one mistake, the other appears. Instant step breaks can not withstand more than one servomotor. I need the exact part and high speed (see photo)!
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Can you post some details about your servos and drives? A manual would be great.
http://www.leadshine.com/productdetail.aspx?type=products&category=servo-products&producttype=brushless-servo-drives&series=ACS&model=ACS806
Re: Mach4 problems when moving.
« Reply #15 on: July 10, 2018, 10:18:42 AM »
Hi,
already the acceleration that the servo is capable of is MORE than what you have set as max acceleration in Machs tuning page.

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I'm sure that the PID settings in the servo drive should be as high as possible, so that you can accurately perform the task of the match
Yes and I see that you've done that but then in Machs tuning you must have limited it or it would fault under acceleration as well as deceleration.

From:
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Software Manual
Of the ACS306, ACS606 V2.0 & ACS806 V2.0

Page 12 / 34 The Error Trace window will give you which of the conditions is causing the fault. You can probably cure 1) and 3), but I don't think you can
cure 2)

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 problems when moving.
« Reply #16 on: July 11, 2018, 01:26:13 AM »
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Yes and I see that you've done that but then in Machs tuning you must have limited it or it would fault under acceleration as well as deceleration.
The problem occurs with any acceleration. Now it costs 3000, put 1500, put 500. At a speed of 30 meters per minute with any acceleration a problem arises. If I leave a little acceleration on the machine, then the car will never be able to catch up to 30 meters per minute.
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Page 12 / 34 The Error Trace window will give you which of the conditions is causing the fault. You can probably cure 1) and 3), but I don't think you can
cure 2)
I have number 2 error.  ;D
I put a braking resistor, Damper PLZ005-G2 ...
On other CNS systems, servodrivers with these settings work well, CycleStop works, no errors occur, the position is not lost ...
Re: Mach4 problems when moving.
« Reply #17 on: July 11, 2018, 02:47:14 AM »
Hi,
the picture in your previous post was a part cut by your machine? If it was then the velocity and acceleration in Machs  motor tuning must be adequate.
If the servos were not fast enough or powerful enough to at least equal the acceleration and velocity settings in Mach your machine would
fault 'following' error and fail to cut accurately.

Clearly your servos are at least big enough and powerful enough to meet Machs demands, except at <CycleStop>.

Lets say you put some really big powerful servos  on your machine that could exceed Machs acceleration and velocity settings. The precision of the cut is still
determined by the acceleration and velocity settings in Mach so the extra big servos haven't improved the precision of cutting but might have enough power
to stop really quickly at <CycleStop>.

I am of the opinion that your servos are big enough that even if you detuned them a bit they would still comfortably exceed Machs acceleration and velocity settings
but be a little less aggressive when decelerating at <CycleStop>. In short you have tuned your servos to be more aggressive than they have to be.

This is my suggestion, 'try detuning your servos a bit so they are still at least as good as the current acceleration and velocity settings in Machs motor tuning'.
I'm hoping that by detuning a bit that you retain the current level of precision BUT REDUCE the tendency to fault.

You don't have to buy anything, just try a slighty less aggressive tuning, if it doesn't work put it back, no harm done.

Craig
My wife left with my best friend...
     and I miss him!
Re: Mach4 problems when moving.
« Reply #18 on: July 11, 2018, 08:45:54 AM »
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the picture in your previous post was a part cut by your machine?
The pictures and videos I laid out are the machine we are talking about. In the photo the details are cut out on the video.
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Clearly your servos are at least big enough and powerful enough to meet Machs demands, except at <CycleStop>.
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Lets say you put some really big powerful servos  on your machine that could exceed Machs acceleration and velocity settings. The precision of the cut is still
determined by the acceleration and velocity settings in Mach so the extra big servos haven't improved the precision of cutting but might have enough power
to stop really quickly at <CycleStop>.
No. I tried the servo motors 1000 W. The problem is even worse. I'm afraid of getting mechanical damage on the machine.
I was looking for a lot of solutions on this problem, only then decided to write to the forum.
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This is my suggestion, 'try detuning your servos a bit so they are still at least as good as the current acceleration and velocity settings in Machs motor tuning'.
I'm hoping that by detuning a bit that you retain the current level of precision BUT REDUCE the tendency to fault.
Craig, thank you for solving my problem.
I will try to explain why I will not change the servo settings.
Mach4 should change the settings for the machine, and not change the machine for Mach4.
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This is my suggestion, 'try detuning your servos a bit so they are still at least as good as the current acceleration and velocity settings in Machs motor tuning'.
I'm hoping that by detuning a bit that you retain the current level of precision BUT REDUCE the tendency to fault.
I made a lot of cars with these servos. Everywhere were the same settings. If you change them, you need to save the settings for each machine separately. A lot of work. If the engine does not work, I can program it and send it to the buyer by mail, he will install it himself. Do you remember what settings were on the car sold 5 years ago? If the car sold 600 pieces?
If my car can move 50 meters per minute with an acceleration of 10,000 meters per second in the square, why should I reduce and not increase?

Re: Mach4 problems when moving.
« Reply #19 on: July 11, 2018, 02:08:35 PM »
Hi,
if you choose to ignore a suggestion that is of course your choice. Maybe someone else will have another idea, unless you ignore them to.

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Mach4 should change the settings for the machine, and not change the machine for Mach4.


Good luck and goodbye.

Craig
My wife left with my best friend...
     and I miss him!