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Re: new computer can't jog faster than 50 ipm?
« Reply #30 on: July 07, 2013, 06:51:30 PM »
thanks for the reply.
I am able to use my older PC which I now have working again. But the plan was to upgrade the computer hardware. I did purchase a Hytechworks USB controller but have returned that unit as I could not get it work properly.
the motors sounded like they were grinding and with the speeds set correctly I was getting 85mm travel DRO indicating 65mm.
I will look and see if there is something else I can purchase to go between the computer and new stepper driver I have just received (has jog controls and a screen on top of package) LPT input.
I will do some more research

Thanks Again Graemecns

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Re: new computer can't jog faster than 50 ipm?
« Reply #31 on: November 22, 2015, 07:36:49 PM »
   I am glad to have stumbled upon this thread. I too have experienced vast differences in my steppers performance with a simple computer change. Computers with very similar specs. I have a video where I was testing my mill during a warm up routine and 300 ipm split on the 3 axis simultaneously. I am lucky to get 60 out of any single axis now.
   Didnt seem to really see a solution here but I do know some lower spec'd PCs have given me some higher machining speeds. I was thinking I was having a machine problem only to disconnect the stepper and find the screws spin freely.  The stepper was stalling. I do have a few SS's but that isnt the point.
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: new computer can't jog faster than 50 ipm?
« Reply #32 on: November 27, 2015, 02:41:54 AM »
Hi all,
my take on the timing variation is

When a stepper is running at max speed, lets say 1200 rpm at 500 step per rev (I use Vexta 5-phase steppers) corresponds to 10,000 pulses per second.
If the pulse generator (ie the PC) is stable the period between rising edges is 0.1ms. If the PC isn't doing as well then the period between pulses will vary.
If we assume just 10% variation the periods will vary from 0.09ms to 0.11ms which corresponds to a variation in speed of 1333rpm and 1090rpm.
Further these speed variations can occur in rapid succession and constitute VERY high accelerations/ deaccelerations and is no wonder the steppers can't
keep up.
My 'big' scope, while old, is quite good and has a histogram function which allows me to measure % variation on a nominally constant pulse stream. I have found
that more than 2-3% severely limits high speed running. At much lower cutting speeds variations of 10 and more % can be tolerated.
I don't believe that the PP, breakout board or stepper controller have that much influence provided they work of course!
As comments in this thread and others make clear an external motion controller is really the only way to eliminate pulse speed variations. I use a single board
Atom based PC for my controller and it works fine so I haven't bothered with an external controller.
I also use an embedded OS (Windows 7) which allows me the choice of what modules run in the machine. I don't run any Ethernet or Ineternet capable modules
as they have security checking processes which 'clogs' things up when trying to run Mach3.

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

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Re: new computer can't jog faster than 50 ipm?
« Reply #33 on: November 27, 2015, 11:35:07 AM »
Craig, Thanks for the response. I dont understand a lot of what you said but it does seem to confirm my suspicion. There are differences in performance.

Though I do have a few flavors of SS, USB and ESS. My thought is that if the computer is causing the issue, while will it not show up via the SS? Trying to quantify just what is responsible for stepper performance is difficult. It isnt as simple as meeting the minimum requirements for Mach or adding RAM or graphics card.

I have had great results from a few PC's over the years via a PP and would like to pursue that avenue before any other approach even if ancient by todays thought.

I see you and a few others are running Atoms or mini itx systems (computers are not my forte either so excuse my terminology if I am off). From what little I can tell, They seem to have integral graphics cards and parallel ports. You dont have any issues running Mach with them? What kind of specs would be required? I wouldnt mind building one. There has to be a youtube video on how to do that! ;-)
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: new computer can't jog faster than 50 ipm?
« Reply #34 on: November 28, 2015, 03:38:15 AM »
Hi Fastest1,
the board I use is a UNIGENS UMB1 which is a MiniITX dual core Atom running at 1.8GHz. The graphics unit (GPU) is built in and shares main RAM.
The NM10 chipset includes a PP. So yes the graphics and PP are effectively included. My board is fitted with 4 Gig of RAM but in fact I wasted money
there, 2 Gig would have been ample and a 64 Gig SSHD. It has one PCI slot which I use for a second PP.
The wee Atom is not a powerful computer by any stretch but has run perfectly from day one. I have seen people spend big bucks on powerful platforms
only to find they don't work as well as an old XP from the ark.
I believe the real reason that this platform works as well as it does is the OS. As I mentioned I installed Windows 7 Embedded. Embedded OS's have been around
a long while, there are a few flavours of XP Embedded for instance. They are typically used by manufacturers for specific or otherwise dedicated devices, Point-Of-Sale
machines as an example. Windows 7 Embedded (Standard) has a very user friendly setup and installation suite which is why I chose it. XP Embedded has 15000 software
modules to chose from when installing, I am no expert and that looked daunting to me.
When you install an embedded OS you can chose certain modules that you want and deselect those that you don't. For my purposes I elected to do away with the modules
associated with Internet and Ethernet security. Those processes have to run in the background continuously and interfere with what you want to run. I don't wish to
expose my machine to the Internet nor put it on any network, I want it to cut chips and nothing else.
If you search for 'single board computer' or 'miniITX' you will be flooded with hits....
MiniITX.com has some very useful combinations that would suit a Mach3 controller for under $100 US.
If you use your existing power supply and monitor and if you have a SATA HD you are there....

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

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Re: new computer can't jog faster than 50 ipm?
« Reply #35 on: November 28, 2015, 10:46:55 AM »
Craig, Thanks again. Do you see any issues running a touchscreen with your set up? Or a similar system?
I want to die in my sleep like my grandfather, not like the passengers in the car! :-)
Re: new computer can't jog faster than 50 ipm?
« Reply #36 on: November 28, 2015, 02:40:24 PM »
Hi Fastest,
I haven't tried a touchscreen so can't say definitively. Certainly the OS has the necessary software to recognise a touchscreen and others use
them so I believe that it would work.
I have found that my budget does not run to such things. If I had several hundred to spare I would uprate my 23 size steppers with planetaries to
grunty 34 size steppers without gear reducers or finish my high torque spindle for spinning face mills or finish my 4th axis drive or buy a direct
drive servo for fifth axis or... and so the list goes.
The main advantage of Mach3/Mach4 is that it is useable software for readily available and cheap computing platforms at a very good price. I accept the
limitations of Mach3 including the PP as the best I can afford. A Seimens 328D controller is on my list but way down there.

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

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new computer can't jog faster than 50 ipm?
« Reply #37 on: November 28, 2015, 03:52:31 PM »
I have been very happy with old computers and Mach. The price is fantastic as well as the forum. It is just when odd unexplainable things get in the way, it is frustrating.


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I want to die in my sleep like my grandfather, not like the passengers in the car! :-)