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Author Topic: CV Simulation Toolpath vs CV Controller Toolpath ???  (Read 2362 times)

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Offline Mauri

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CV Simulation Toolpath vs CV Controller Toolpath ???
« on: January 12, 2017, 07:54:36 PM »
hi,
I am having major differences between CV with Mach4 simulator and CV with Mach4 and Controller on the Toolpath Display and Timings to completion.
I have tried CV = 0/10/25/50/100 with the Mach4 and Controller running and have viewed each time the Toolpath Display and reported the time taken.
I have compared these against CV with Mach4 Simulation Mode on the Toolpath Display and recorded time taken to complete.
I have found that all CV’s are faster to completion with Mach4 and Controller, but are visually worse even comparing CV=0 with Controller and CV=100 with Mach4 Simulation mode on the Toolpath Display.

Could it be that the data is flowing faster to the Controller than the Toolpath Display and hence loosing data for display on the angles?
If not can anyone explain why?

I have many examples if some one needs them to explain.

Regards,
Mauri.

Offline smurph

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #1 on: January 14, 2017, 12:01:59 AM »
Data is flowing to the controller first, then we have to wait on a position update from the controller to update the position on the tool path.  We depend on the motion controller to give us updated positions and since there is nothing real-time about it, there will be positional "gaps".  So it really depends on how often the motion controller sends Mach position data.  No two motion plugins are the same.  For instance, this update rate is configurable in the Galil plugin and can go as low as 8ms if the PC will handle it.  But a lot of them may be as slow as 100ms.  A slower update rate will have the effect of chopping off a corner in the tool path display as Mach basically draws a line from the last reported position to the current one. 

Steve

Offline Mauri

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #2 on: January 14, 2017, 05:24:37 AM »
Steve,
Thank you for the information, I had a feeling that this was happening.
On my Controller Plugin the Polling Frequency is 10Hz to 250Hz and I have the setting at 100Hz as recommended with the Controller information.
Previous versions of the Polling Frequency had 2Hz to 250Hz.
It talked about Significant Network Traffic and CPU load, however if my PC is fast and directly connected it should not be an issue.
I will enquire with the manufacturer of the card more about this setting.
At least now I can calculate a cut time that was close to Mach3 with its CV setting (CV Distance Tol = 0.01 and Stop CV on angles >49), which equates to about 75 on all CV 180 angles with Mach4 and this reports a reasonable good Toolpath finish using 30Degree 0.05mm Radius cutter on a 2.5D surface.
Thanks Steve,
Regards,
Mauri.

Offline Mauri

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #3 on: January 14, 2017, 01:40:46 PM »
Steve,
I have been advised that HiCON Integra Plugin can provide faster updates.

From Marc of VitalSystem a very helpfull Company with great CNC products.

Hz, or Hertz, is a unit for frequency (cycles/second).

To get the Poll interval:

PollInterval = 1000 / UpdateFrequency

This means, with an update frequency of 200Hz, you will effectively have 5ms update intervals.

I would really only recommend going up to 200Hz which is probably more than enough responsiveness as far as PC-based motion control goes. There are times when even more responsiveness is required, which is why we have the HiCON and DSPMC macros.

So since I had 100Hz that would have been equal to 10ms.
I will give the 200Hz a go and see what happens.

Regards,
Mauri.

Offline Haik

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #4 on: May 04, 2017, 12:50:21 PM »
Hello Mauri,

I've read some of your posts and am impressed with you understanding and knowledge, particularly with the communication of M4 to controller. I'm hoping you can help.

I'm deciding between Galil DMC-4080 and the HiCON for my industrial router with nema42 steppers. Since 2010 I've been on Smootstepper ESS, It's been a punishing 7 years.

Moving to M4, but am still on M3, command speed varies motion rate greatly. This is most evident on CV moves. The SS has something they call “controller frequency”, it’s adjustable and has a max of 4khz. This controller frequency directly affects Mach’s CV (constant velocity) feedrate output.

Motor tuning aside, an example is on toolpaths with thousands of tiny 0.002” moves of 5 degrees or less (at F140) a controller freq of 1khz produces an actual feedrate of appx 10 ipm.

Bump the SS controller freq to 4khz and feedrate output jumps to appx 60 ipm with no added jerk at the machine. Motor velocity and acceleration settings and performance are unaffected, just commands are occurring at a higher rate providing an increased feedrate output. The SS plugin crash rate dramatically increases at 4khz.

Better gCode is a solution, but the M3/SS bottleneck exists even with direct cat5 connection of fast computer to SS. The SS plugin and/or controller are to blame*.

My big question is… do you think the HiCON (with M4) will outperform the SS with regard to processed commands per second?

Any of your thoughts are deeply appreciated. Thanks!

-Haik

*SS controller freq, number of lines to precalculate and M3 look ahead lines, CV settings, motor tuning and more have all been thoroughly exercised.

Offline smurph

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #5 on: May 04, 2017, 01:33:17 PM »
I would not use a Galil to control steppers. 

Steve

Offline Haik

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #6 on: May 04, 2017, 02:36:55 PM »
There are just so few choices for quality motion upgrades. Vital Systems and Galil take what they do seriously. The "hobby" approach and perpetual beta of others have had huge costs for me. I'm getting closer to just buying a new Biesse or Thermwood system. My old Therwood C5 (w/atc) is mechanically upgraded and is very tight.
It would be great to have a router with 3ph AC servos, I'm just not looking forward to the service contracts and s/w addon costs.
I am awaiting some info from Vital Systems. I've asked about Spartan3 FPGA cababilities on this topic.
This is my last hope for reaching a quality bar that includes stability and some resemblance of performance.
I just looked at several of your other posts, there's a lot of depth and detail that is also helpful. Thanks for the reply!
« Last Edit: May 04, 2017, 02:38:35 PM by Haik »

Offline Mauri

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #7 on: May 04, 2017, 05:07:16 PM »
Haik,
HiCON controller was basically the first that would run properly with Mach4, It was used with Mach3 very successfully.
Our HiCON has had no issues with running Mach4 and if any come up with the Mach4 updates the people at HiCON quickly provided an update to the firmware and plugins.
They have a number of add-on cards if required to hook up any configuration of equipment motors and drivers.
They work with servos or steppers.
They may cost a little more but I am sure you will be happy.
Remember that good motors and driver are also the heart of smooth motion.
Make sure if you go ahead and purchase one that you gather all the information you need to make your controller.
Most of this is on their website, so download it and print it and read it.
Regards,
Mauri.

Offline Haik

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #8 on: May 04, 2017, 05:59:46 PM »
Thanks for the reply!
If I may ask... What other controllers run Mach4 properly (up to $5k, cost is not a factor)?

Kind Regards,
 - Haik

Offline Mauri

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Re: CV Simulation Toolpath vs CV Controller Toolpath ???
« Reply #9 on: May 04, 2017, 06:16:13 PM »
Haik,
All controllers out there are continually making changes to suit the newest version of Mach4.
HiCON has been the one that has worked out of the box.
In the past I used Smooth Stepper, but have always had some issues.
PMDX may be worth an enquiry.
Regards,
Mauri.