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Author Topic: Unstable pulsing under Windows 7  (Read 5146 times)

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Offline TKL

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Unstable pulsing under Windows 7
« on: January 21, 2017, 11:14:22 AM »
About a month ago I installed Mach3 on an IBM ThinkPad laptop, with docking station to provide LPT output, running on Windows 7.  I use it for the control of a Proxxon milling machine using a breakout board and stepper motor drivers from Probotix.

Everything worked OK for a while, then something happened. The computer was online and received some Windows updates that were installed automatically. After that the operation of of the axes became unstable. Jogging at high speed isn't really high speed anymore. The speed varies, and the sound from the motors is like crushing rocks.

I did first suspect that the Windows updates were the source of the problem, so I reinstalled Windows 7 and downloaded and installed Mach3 again, but it didn't help.

When I run the driver test I consistently get the message "Pulsing too fast".
From the pulse test window I read the following values:
Pulses per second: Varies in the range 4000-6000
Shortest time: typically 5-20 microseconds
Longest time: typically 60-80 microseconds
Max variation: typically 40-60 microseconds

The "Time between pulses" graph show a massive array of spikes between 32 and 64 microseconds, sometimes the graph looks like a horizontal solid wide bar.

Apparently there is something wrong in the low level interaction between Mach3 and Windows.

Is there anybody who can help me solving this problem?

Offline Tweakie.CNC

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Re: Unstable pulsing under Windows 7
« Reply #1 on: January 22, 2017, 02:23:33 AM »
I think you were just lucky to get it working the first time. Laptops (docking station or not) are not recommended when using the parallel port. The recommended way  with Win7 and a laptop is to use an external motion controller (ESS, UC100, etc.).

Tweakie.
« Last Edit: January 22, 2017, 02:25:38 AM by Tweakie.CNC »
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Offline TKL

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Re: Unstable pulsing under Windows 7
« Reply #2 on: January 22, 2017, 02:30:05 PM »
OK, but can you explain in more technical terms why it doesn't work on laptops? Is it an issue related to differences in hardware, in that case which difference? Or is it a software difference? I assume that basically the Windows 7 OS is the same no matter which computer it is running on. Is there a difference in the computer's BIOS?

Offline Tweakie.CNC

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Re: Unstable pulsing under Windows 7
« Reply #3 on: January 22, 2017, 03:18:02 PM »
Very very basically there is an incompatibility -  laptops use various power saving features and Mach3, when using the parallel port, places a high demand on processor and graphics. I have one old laptop that works beautifully using the parallel port and two newer laptops that just don't work well with pmcia parallel port cards. This situation was discovered way back by Artsoft - the result is that laptops are not supported for parallel port operation.

Tweakie.
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Offline TKL

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Re: Unstable pulsing under Windows 7
« Reply #4 on: January 23, 2017, 04:41:37 AM »
Thank you very much Tweakie, this was an understandable explanation. I have a couple of fairly old laptops. I will try one of them with Windows XP OS

Offline Tweakie.CNC

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Re: Unstable pulsing under Windows 7
« Reply #5 on: January 23, 2017, 05:06:03 AM »
You may be lucky.  ;)

Tweakie.
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Offline TKL

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Re: Unstable pulsing under Windows 7
« Reply #6 on: January 24, 2017, 03:27:55 PM »
I decided to try to step back one generation of OS on my ThinkPad, so I installed Windows XP. I cleaned out everything, including wireless internet. I then reinstalled Mach3.

After that Mach3 has been running rock steady with no "rock crushing" in the stepper motors. Everything simply works fine. It seems that the problem was Windows 7, not the laptop.

I am happy since the ThinkPad is quite compact and doesn't take up much space on my workbench. I didn't like the idea of having a tower and a large display taking up a lot of space.

Offline Tweakie.CNC

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Re: Unstable pulsing under Windows 7
« Reply #7 on: January 25, 2017, 01:24:24 AM »
Excellent news.  :)

Tweakie.
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