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### Author Topic: Tempest Planning - Preliminary information and testing  (Read 328950 times)

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#### montabelli

• 7
##### Re: Tempest Planning - Preliminary information and testing
« Reply #130 on: March 25, 2010, 09:34:21 AM »
Art,
I know that the notion I had as I awoke this morning is an over simplification but since the 2axis motion of tempest is so smooth, I thought I'd throw it out there. 2 axis motion in g17, 18 or 19 is very good when the third axis is thrown in it starts to have a problem. I was wondering if it would be possible to use your algorithm to control the two primary axies and  pulse the third proportionally to the move with the other two, using the assumption that the third is usually going to be within the jerk parameters of the other two. since the 4th is usually a rotary, I wonder if it could be done the same way?

#### ART

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• Tough as soggy paper.
##### Re: Tempest Planning - Preliminary information and testing
« Reply #131 on: March 25, 2010, 11:24:03 AM »
REally, 2 axis is good and 3rd axis is rough?  Or do you mean your using x,y an dA for example?
Its true that using rotart is not perfect as yet in tempest, Ive focused primarily on cartesian...
but using x,y and Z should be fine?

Art

#### Bruce Griffing

• 15
##### Re: Tempest Planning - Preliminary information and testing
« Reply #132 on: March 25, 2010, 11:54:34 AM »
Art-

#### ART

• 1,702
• Tough as soggy paper.
##### Re: Tempest Planning - Preliminary information and testing
« Reply #133 on: March 25, 2010, 12:54:56 PM »
Bruce:

>>The setup of acceleration in M3 is done starting at rest.   The user tunes the acceleration based on how the machine performs in this test - with no control of jerk (pretty high at end points) as I understand the test.   As it says in the docs - the limit is set mostly done by sound and pushing to failure and them backing off.    I believe that if the setup were done with a jerk limit, the peak acceleration that the user would end up with would be higher than the acceleration you end up with in the standard test.   This is because higher peak accelerations would be possible since they would occur (in the test) when the machine was already moving.  This of course implies a different acceleration setup for Tempest M3 than stock M3.  Is that clear?

If I understant you , thats only true in non-linear acceleration. In Mach3 ( linear accel), setting it to a jerk limit woudl reduce the end accel and speed as its that that causes the jerk in the first place, in Tempest ( sinusoidal accel), its very true that the accel shoudl be set with a jerk limit. It uses MAch3's simply because tempest is mach3 with sin accel, so I didnt rewrite the motor tuning. In fact in Tempest one shoudl set the accel normally, then increase it by about 30% as tempests use of sinusoidal accels will allow the motors typically to do about 30% better accel.

However, since sine based accel uses about 30% more time than linear ( on average ), the end speed is then simplyequalized, not increased ( on average) by havingthe accel set higher.

The problem in tempest is that while Gcode motions use sine accel, jog doesnt, so you have to be carefullnot to make jog too jerky when tuning. If Jog was sinusoidal as well, then simple
motor tuning by sound woudl be fine.
I advise simply tuningmotors in jog as high as you can without losing steps.. Tempest can usually handle that high an accel..

Art

#### Bruce Griffing

• 15
##### Re: Tempest Planning - Preliminary information and testing
« Reply #134 on: March 25, 2010, 02:00:57 PM »
Ah - the point that Tempest can handle higher acceleration is what I was after.  How it is set up probably does not matter.  Tnx.

#### ART

• 1,702
• Tough as soggy paper.
##### Re: Tempest Planning - Preliminary information and testing
« Reply #135 on: March 25, 2010, 02:19:39 PM »
Bruce:

Yes, since its 5th order, it can handle Gobs more...

So feel free to turn it up.. till jog starts to fumble, then back off a bit..

Art

#### ger21

• 6,295
##### Re: Tempest Planning - Preliminary information and testing
« Reply #136 on: March 25, 2010, 05:29:01 PM »
I'd like to see Tempest as it is right now as an option in Mach3. For normal 2.5D routing, it blows away Mach3's planner.
Gerry

2010 Screenset
http://www.thecncwoodworker.com/2010.html

JointCAM Dovetail and Box Joint software
http://www.g-forcecnc.com/jointcam.html

#### TOTALLYRC

• 861
##### Re: Tempest Planning - Preliminary information and testing
« Reply #137 on: March 26, 2010, 04:20:29 AM »
Bruce:

Yes, since its 5th order, it can handle Gobs more...

So feel free to turn it up.. till jog starts to fumble, then back off a bit..

Art

Hi Guys,
On my DSPMC powered mill the motor tuning was able to be set much higher in Tempest than with the standard planner. I think as much as 30% higher. Since the DSPMC support S-curve acceleration "natively" I asked Rufi if he could add S-curve jogging and he said he could. Unfortunately it is not high on his to do list. When I get back to running my mill more I will see (Bug him) if he can get this done.
As I told Art during one of my posts I have never seen my mill move that fast and that smooth at the same time as when running Tempest.

Here is to more Tempest work.

Art, not sure it it would be applicable but can tempest be used in turn? Would turn benefit from the motion planner?
I am entering the wonderful world of round parts and was just wondering.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.

#### ART

• 1,702
• Tough as soggy paper.
##### Re: Tempest Planning - Preliminary information and testing
« Reply #138 on: March 26, 2010, 11:05:02 AM »
Hi Mike:

It woudl give a smoother finish..

By the way, the DSPmc supports SCurve natively because Tempest sends the data in 1ms trajectories, so
when running tempest, any device, printer port, G100, SS etc.. are all supporting SCurve, since its Tempest
that is supplying the information on position.

Art

#### TOTALLYRC

• 861
##### Re: Tempest Planning - Preliminary information and testing
« Reply #139 on: March 26, 2010, 03:04:06 PM »
Hi Art,
I guess what I should have said is that the DSPMC has s-curve built in so to speak. When using the axis work software to set it up you get the option of trapezoidal or s-curve motion. This would mean that all the ground work for s-curve jogging has been laid and that it shouldn't be that tough for Rufi to implement.
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.