Counter balancing Z axis..

[ger21]

It's not a communication issue.
Mach3 basically takes over windows, in order to be able to do what it does. Anything that takes CPU cycles away from Mach3 can cause issues.
Keep in mind that at the lowest kernel speed, Mach3 has to be able to output 150,000 steps every second. (6 axis x 25Khz) It's also doing a bunch of other stuff at the same time.

are there ways to improve the performance

When Mach3 is running, don't do anything else with the PC.
Or, buy an external motion controller that handles all the step pulse generation. But, even then, it's a good idea to not do anything else on the PC while the machine is running.

[adam_m]

Since its CPU intensive, will a multi-core CPU increase the efficiency and how about RAM?

How about shutting down backgroud process, etc. to increase the effectiveness and chance of success? heck the OS itself has cart blanch of the CPU and who knows when its going to try something.

Maybe this is a better discussion for Newfangled solutions.. I may kick up a thread there.

Thanks.

Adam,

[ger21]

A faster PC may help, but it won't guarantee anything.
Older PC's tend to work better with Mach3 than more modern ones. And you are limited to 32bit versions of Windows 7 or older with the parallel port.

You should NOT have any antivirus, or screensavers running. And the more background processes you can eliminate, the better.


I run Mach3 on a 1Ghz Pentium III, with 512MB of RAM, and it's 100% stable, all of the time.

[adam_m]

Thanks Gerry.

Looks like I'll be hunting up an older motherboard and CPU...

[louieatienza]

Thanks Gerry.

Looks like I'll be hunting up an older motherboard and CPU...

You can just buy an older P4 Win7 PC chat or under $100, maybe even free. The older ones still have a parallel port on-board.

[ger21]

It may be easier to just buy a motion controller, like a UC100.

[adam_m]

I'm guessing there is more stability in the USB port from a PC than the parallel port, which is why this is an acceptable solution?

If going with an older M/B/CPU am I taking a chance with compatibility and running into the same issues as opposed to just ponying up to the UC100, do they have a US seller?

Adam,

[109jb]

No. The USB port is in many ways even more "unstable". but the USB solutions move the time critical tasks from the computer to the USB device. The USB device, whether a uc100 or whatever, contains a micro controller or fpga of its own that handles the time critical stuff.

[ger21]

I'm guessing there is more stability in the USB port from a PC than the parallel port, which is why this is an acceptable solution?

No.
With a motion controller, the motion controller has a processor that generates the step and direction pulses, instead of the PC doing it. Mach3 sends buffered lower level motion commands to the motion controller, which takes a lot of the pressure off of Mach3.

For a little more money, an Ethernet controller like the UC400E or ESS is considered by many to be a better choice.

[louieatienza]

I'm guessing there is more stability in the USB port from a PC than the parallel port, which is why this is an acceptable solution?

If going with an older M/B/CPU am I taking a chance with compatibility and running into the same issues as opposed to just ponying up to the UC100, do they have a US seller?

Adam,

The parallel port is actually pretty stable, especially onsidering the interface is abot 40 years old. EPP mode is capable of 2.5Mb/s so that's not the bottleneck.

The thing with the USB and Ethernet controllers is deciding on whether to use Mach3 with the required plug-in or using the controller manufacturers' own controller softwate. Mach3 is more like a DOS program living within Windows, while the newer software out there is fully Windows compliant - meaning they're capable of running Windowed, sharing resources, even running in the background... Not that it is advisable to do that.

[OlfCNC]

The bottleneck about parallel ports with Mach3 is Windows which is not realtime.
A motion controller can give you much more stable signals than any parallel ports.
In my case my machine is running 2 times faster with the uc100 than it was with a parallel port and that is because the signal timing is much better.
I could talk about stability too... and an ethernet controller like a uc400 is another step-up in the game.

[louieatienza]

The bottleneck about parallel ports with Mach3 is Windows which is not realtime.

Yes, but the price we pay to be able to have an infinite amount of hardware configurations, and still be able to run Windows. I think it started with Win95/NT...

[OlfCNC]

es, but the price we pay to be able to have an infinite amount of hardware configurations, and still be able to run Windows. I think it started with Win95/NT...

For me possibly loosing steps when Windows gets "overloaded" is a too high price.
I rather just drop in a motion controller.
I can even watch videos or design new toolpaths on the same computer while machining.

[louieatienza]

For me possibly loosing steps when Windows gets "overloaded" is a too high price.
I rather just drop in a motion controller.
I can even watch videos or design new toolpaths on the same computer while machining.

I have a video running my small router with an EdingCNC card, while I'm online surfing CNC Zone, with my CAD/CAM software running... no problems whatsoever. But really, old computers are so cheap nowadays, and still fast enough, that for most purposes, motion controller isn't needed.

[adam_m]

I guess my most practical approach would be to dig up an old PC... but then I worry about once again running long jobs and losing steps. I mean does it make sense to just pick up a motion controller and be done with it and avoid the "what if" scenario's... it seems like lots of users are not having issues so maybe this is just an oddity with my hardware and software that I have running in conjunction with Mach...

Well, we've certainly gotten off topic of a "counter balance for z" but I think this is probably the right path for me.

Thanks for all the great feedback and discussion.

Adam,

[OlfCNC]

I guess my most practical approach would be to dig up an old PC... but then I worry about once again running long jobs and losing steps. I mean does it make sense to just pick up a motion controller and be done with it and avoid the "what if" scenario's... it seems like lots of users are not having issues so maybe this is just an oddity with my hardware and software that I have running in conjunction with Mach...

Yup, we gave you our ideas, now it is up to you what you will do.

[OlfCNC]

I have a video running my small router with an EdingCNC card, while I'm online surfing CNC Zone, with my CAD/CAM software running... no problems whatsoever. But really, old computers are so cheap nowadays, and still fast enough, that for most purposes, motion controller isn't needed.

I thought the discussion was about Mach3+LPT port wasn't it? I mean I anwered in this context since I have no clue about EdingCNC, so I can't comment on that. I don't even know if it runs with LPT ports?!

[louieatienza]

I guess my most practical approach would be to dig up an old PC... but then I worry about once again running long jobs and losing steps. I mean does it make sense to just pick up a motion controller and be done with it and avoid the "what if" scenario's... it seems like lots of users are not having issues so maybe this is just an oddity with my hardware and software that I have running in conjunction with Mach...

Well, we've certainly gotten off topic of a "counter balance for z" but I think this is probably the right path for me.

Thanks for all the great feedback and discussion.

Adam,

Your "what if" scenarios are tied into you trying to multitask on your computer used for machine control. Sure you COULD potentially with an external motion controller, but it is not considered good practice; you can easily have a buffer underrun or overrun for whatever reason. I've run jobs 5-7 hours long while I slept, on an old Win7-32 machine running off the parallel port. Really, and I've mentioned this before, unless you have to run very high microstep rates, maybe you have servos with high encoder count, or have to run the machine at very high speed (i.e. laser engraving) it's likely unnecessary that you'll reap an advantage by using an external motion controller. Obsolescence an issue? I run part-time a Bridgeport clone retrofitted with a Centroid control that runs on a 386... it easily achieves over 200ipm, way faster than necessary for its 4500rpm spindle. Been running since 1997-1998. The big limitation is transferring files via 5-1/4" floppy disk...

[adam_m]

OlfCNC, originally this thread was started to find a way to counterweight my Z drive I thought that was my issue. I think its really turned out to be a PC problem.. time will tell but I bet the guy's are correct.

I think I can scrounge up an old Dell Windows XP machine that I can try to use... I'll post back just to close the loop on the thread with my findings.

If that doesn't work then I'll certainly grab a motion controller.

Adam,

[Jim Dawson]

Your "what if" scenarios are tied into you trying to multitask on your computer used for machine control. Sure you COULD potentially with an external motion controller, but it is not considered good practice; you can easily have a buffer underrun or overrun for whatever reason. I've run jobs 5-7 hours long while I slept, on an old Win7-32 machine running off the parallel port. Really, and I've mentioned this before, unless you have to run very high microstep rates, maybe you have servos with high encoder count, or have to run the machine at very high speed (i.e. laser engraving) it's likely unnecessary that you'll reap an advantage by using an external motion controller. Obsolescence an issue? I run part-time a Bridgeport clone retrofitted with a Centroid control that runs on a 386... it easily achieves over 200ipm, way faster than necessary for its 4500rpm spindle. Been running since 1997-1998. The big limitation is transferring files via 5-1/4" floppy disk...

Louie, while I agree that computer multitasking on a running machine tool is not a good idea, it is possible to do so with an external motion controller. I'm glad to see there is someone else that is crazy enough to run ''lights out''. Like you, I run lights out for much of my router work which generally runs 9-12 hours per run, but normally I don't do that with my mill because the runs are usually much shorter. If I were using a open loop system and/or without an external motion controller that has fail-safes programmed in I would not be comfortable doing that.

The primary advantage to using an external motion controller is that it is doing it's own trajectory planning and on-the-fly position error correction, in addition to taking the load off of the Win computer. This is typically a much more accurate system than running from a parallel port. This is how I manage to hold mill tolerances on my router, typically < +/- 0.001 inch. Buffer underrun/overrun should not be a problem in a properly written CNC program.