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Author Topic: new computer can't jog faster than 50 ipm?  (Read 16747 times)

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Re: new computer can't jog faster than 50 ipm?
« Reply #10 on: April 05, 2009, 04:47:46 PM »
I tried removing memory, installing a PCI-e video card, a few more settings in Mach, and BIOS, all with no success. 

The old computer was still running an old version of Mach3 that had the old Mach2 driver test.  That shows full height spikes on every screen refresh, but I wonder now if those were false spikes.  I copied the new driver test over to the old computer, and it was REALLY nice compared to the new computer.  No doubt that's the issue.  I also put a logic analyzer on pins 2 and 3 for the X axis, and verified the same occasional pauses in step pulses, so there's no doubt that the timing is not nearly as stable on the new computer. 

That leaves me with the question of why this is a problem.  The driver test program declares that the timing is "excellent", and the motors certainly don't expect the next pulse at any particular time.  They would just see it as a speed change, as you have when you ramp up or down in speed. Best I can figure, the motor controller must be the device that's having an issue with this.  Not much to do about that really, but I'd bet that another brand of controller might work fine. 

In all my research, I've noted that some controllers generate a hardware timer, that's fed back to the software for timing control.  Software that uses this clock looks for it on pin 10 of the parallel port, and if your controller doesn't generate it's own clock, you can use a stand-alone board to supply it.   Pity that Mach3 can't accept an external clock, because that would be a pretty easy fix to the timing problems. 

Bottom line, I can't argue with the need for stable timing, at least in the case of the Probotix motor controllers.  It also makes sense to let a dedicated  external device handle the chore, as is done with the external timers I mentioned above.  In this case, the best option appears to be the SS, so I officially give up.  SmoothStepper order placed.  I sure hope it works, because otherwise I'll be stuck at 50 ipm. 

Thanks for all the comments and suggestions.  Now get to work Jeff  ;D

Rusty
   

 

Offline Chip

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Re: new computer can't jog faster than 50 ipm?
« Reply #11 on: April 05, 2009, 05:10:11 PM »
Hi, Rusty

Sent you a PM message, Top left of this screen, Click on your messages.

Chip

vmax549

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Re: new computer can't jog faster than 50 ipm?
« Reply #12 on: April 05, 2009, 06:03:31 PM »
Have you actually gone and looked at your drive settings? I have seen MACH change these on a reloading of mach.

Sounds like the ACCEL is way to high. THe 25k mode should run fine on just about any modern comp.

Double check your settings ALL of them. (;-)

(;-) TP
Re: new computer can't jog faster than 50 ipm?
« Reply #13 on: April 05, 2009, 10:56:32 PM »
Have you actually gone and looked at your drive settings?

Probably not more than 50 times.  I'll probably have nightmares about them  :-)

Rusty
« Last Edit: April 05, 2009, 10:58:27 PM by 13brv3 »

Offline Graham Waterworth

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Re: new computer can't jog faster than 50 ipm?
« Reply #14 on: April 06, 2009, 01:09:49 PM »
Have you copied your licence file onto the new computer?

Graham
Without engineers the world stops
Re: new computer can't jog faster than 50 ipm?
« Reply #15 on: April 06, 2009, 01:13:26 PM »
Have you copied your licence file onto the new computer?

Graham


Yes.  No problem with the license. 
Rusty

Offline Graham Waterworth

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Re: new computer can't jog faster than 50 ipm?
« Reply #16 on: April 06, 2009, 01:18:43 PM »
Is the LPT 3 volt or 5 volt on the output pins?

Graham
Without engineers the world stops
Re: new computer can't jog faster than 50 ipm?
« Reply #17 on: April 06, 2009, 01:43:40 PM »
Both computers have just under 5V on the parallel port pins. 

I spent quite a lot of time on this over the weekend, including using a logic analyzer to watch the step pulses. It's clear that the new computer's timing isn't as stable as the old computer was, and there's nothing that can be done about that. The only part that bothers me is that the driver test says my timing is "excellent", so I presume the Mach3 folks consider this OK.  I have to wonder if the timing issue isn't more of a problem with my Probotix controllers.  Perhaps they're just not forgiving of slight timing changes.

Since I ordered a SmoothStepper from Jeff, it's not such a big problem now, but I don't like to be beaten by something like this, so it still bugs me a bit. 

Thanks,
Rusty


 

Re: new computer can't jog faster than 50 ipm?
« Reply #18 on: April 07, 2009, 04:17:43 PM »
I had to go to a meeting today, and found myself about a block from a decent computer store. For the sake of ruling out everything, and to satisfy my curiosity, I picked up a PCI to parallel adapter card.  As expected, it didn't make any difference, and it makes sense that it wouldn't.  The driver test shows the problem, and doesn't actually use the parallel port for the test.  No harm done trying it, since I can always return it. 

Cheers,
Rusty
   
Re: new computer can't jog faster than 50 ipm?
« Reply #19 on: April 09, 2009, 05:51:46 PM »
SmoothStepper saves the day! 

http://www.machsupport.com/forum/index.php/topic,11152.0.html

Thanks,
Rusty