motion control card

[automan1]

I am starting to build a 7' X 9' cnc plasma doubling as a router 3' of z mach 3 states in it's manual that a motion control card takes a lot of the work or stress off the computer and I suspect it can help the accuracy of the motion opening up more options than the printer pins allow. This machine needs to be very accurate as it is the trial run for a Taurus gantry mill 6'x10'x42"z. So my long winded question is who makes a good motion control card that will work with mach3? I need quality not cheep.

[ger21]

Mach can use certain Galil cards, but I'm not sure how complete the galil plugin is. You should ask on the Machsupport forum. I think there's a Galil section there.

You can also use a Smoothstepper, www.warp9td.com. The Smoothstepper plugin is still considered in beta, as there are still some issues that need to be resolved, but it is actively being developed.

[H.O]

I depends.... (Don't you just love to hear those words.) If your servodrives are digital with Step & Direction interface then you should probably look at the Smoothstepper. If you're running large (or small for that matter) industrial servos with analog velocity or torque control then you should have a look at the DSPMC/IP from Vital Systems.

Now, you mention this is a plasma machine so you definelty should look into if the soultion you go for supports THC if you want to run that. The Smoothstepper claims to be a "transparent" solution, dissconect your LPT-cables and connect them to the Smoothstepper and go but it's not just there yet. Basic functionallity is there and works really good but there's still some details to be worked on. (And are being worked on if I'm correctly informed).

I have no personal expereince with the DSPMC/IP but there are a thread or two on the zone and for first hand info make sure to contact Rufi at Vital Systems. I'm sure he'll tell you if his unit isn't suitable for what you're doing.

Both of these units are acively being worked on, then there's also the Galil cards (some of them is supposed to work with Mach3) and the G100 but I don't think anybody is working on the Galil solution any more and I know that the G100 development has stalled completely so don't go there.

Good luck!
/Henrik.

[Torchhead]

If your intent is to use the embedded plasma logic in MACH with a Torch Height control then some of the solutions mentioned won't work.

The THC logic in MACH is basically a "servo" loop. The external THC electronics measures the gap voltage (typically 1 volt or less of change gets acted on) and sends a signal via the higher speed inputs of the parallel port. It's important that the loop time not be to wide or the THC fails to track properly. The Smooth Stepper buffers axis moves which introduces some delay and more important, INPUTS are not handled real time. Since you have one set of wires to do everything something has to get priority. So any integrated THC with MACH needs real time input speeds.

Any system that will not let the parallel port inputs be at the normal read speed (or won't let you use the parallel port at all) is not going to work with plasma.

Our 3rd generation Digital Torch Height Control is optimized to run with MACH. We have move all of the readout and presets to the MACH screens. We have a custom pop-up that allows different setups for as many types of cutting and material as you want.

Since the person is building a plasma table they would be advised to buy the controls from someone that understands CNC plasma cutting. There are noise challenges and motion requirements that are vastly different than routers and mills.

The ability to write custom plug-ins for MACH makes it a flexible and very cost effective software control. We have taken advantage of the open format and use plug-ins to control the communication with our products.

I invite the original poster to research our MP3000-DTHC. It's the only single port interface that can handle all of the inputs and outputs for full table operation AND the DTHC.

We even sell a low cost "HIGH SPEED CNC INTERFACE CARD" (it's actually just a PCI parallel and serial port card) for PC's with only USB.(:-)

It's my contention that USB will have technical limitations that preclude it from being a full CNC interface.

http://www.CandCNC.com/MP3000-DTHC.htm
http://www.CandCNC.com/DTHC_Detail.htm
http://www.CandCNC.com/PlasmaPakPriceChart.htm


TOM CAUDLE
www.CandCNC.com
Totally Modular CNC Electronics.

[ktb100]

Quote:

It's my contention that USB will have technical limitations that preclude it from being a full CNC interface.

Hi Tom,
100ums is pretty quick for speed. We are coming out of the PC with USB then transferring from USB to shielded RJ485 cables. by keeping the USB cable short and near the PC, noise problems like what you have seen in the past are gone. I have personally used a megger and applied 18V to the ground of a machine to mimic noise with our system using USB. I was unable to loose a step or cause the board to fault. In addition, I wrapped the cables around a 15 HP VFD, laid them across a 220/110 transformer and the main 220V incoming machine power. Still working The length has been tested from the USB board to the motion control board to 200' without a lost signal and no boost required. I don't see the need to test it at a longer distance. I am pretty happy with how it turned out. I think USB has a future with CNC. Actually, I am positive it does.


Regards,

Kirk

[Torchhead]

It's not just about spinning motors. That has been working with USB for years. Flashcut uses it, several home owner machines (like the Sears thingy) uses it. Where it falls down is you have to buffer the axis information on the downstream end and that disconnects any real time interface. In a lot of circumstances that does not matter. In a more advanced installs it does.

We skipped USB and started working with Ethernet. It's already differential signaling, it's protocols are better for shared access and it's designed for high speed communications rather than to run a keyboard and mouse. 10MBt is easy to do and virtually every computer has an Ethernet port. You can evne have a dedicated Ethernet setup. It will work wireless and it's cheap. Even then there are limitations because you are going from a 8 bit bus signal (parallel) to a single bit serial and then back again. As an engineer you have to sit down and look at everything the product has to be able to do then look at the best communications to achieve that at a price point. Using a 100.00 solution to avoid a 15.00 one because of perception is not always the best engineering choice. We as engineers all suffer from a "wow, it would be neat to do it with the new whizbang #### chip" [part of the neat tools syndrome]. We get excited about the technology and the challenge because that is what motivates us.

So let's stop calling it a "Parallel Port" . Lets' call it a "High Speed CNC Interface Card". Maybe if I raised the price from $15.00 to $150.00 it would get more respect. The parallel port may die someday, but as long as the OS will support it, it will continue to be a viable solution.

It was not too long ago that PC's for CNC controllers were not considered more than a toy. Then when they were, a lot of the solutions had expensive proprietary interface cards and software. Some of the DOS software started using the parallel port and then Art came along and figured out how to hack Windows to give him access to the timer and the rest is history.

TOM Caudle
www.CandCNC.com

[ktb100]

Wow,

Did I strike a nerve or are you always this defensive?

Quote:

"In a lot of circumstances that does not matter. In a more advanced installs it does".

So you're saying that buffering data is OK in a lot of circumstances. I would guess that most systems are not advanced, especially on the hobby side.

"We skipped USB and started working with Ethernet. It's already differential signaling,"

And USB is not?

"it's protocols are better for shared access"

why do you need to share the access to your CNC? controller?

"and it's designed for high speed communications rather than to run a keyboard and mouse."

And USB is not designed for high speed communications? You're only describing the low speed portion of the USB spec. Full speed is 12 Mbps, and High Speed is 480 Mbps.

"10MBt is easy to do and virtually every computer has an Ethernet port"

If 10 Mbps is so easy to do, then why did the G100 fail?

"Even then there are limitations because you are going from a 8 bit bus signal (parallel) to a single bit serial and then back again"

So are you saying that all of your CNC applications use a maximum of 8 bits of data? I doubt that. When you require more than 8 bits you need to send the data words serially. If you need to transfer 32 bits of data, you need to send four 8-bit words. That is serial data transmission. It just happens that your data bus is 8 bits wide instead of 1 bit wide.

"We as engineers all suffer from a "wow, it would be neat to do it with the new whizbang #### chip" [part of the neat tools syndrome]. We get excited about the technology and the challenge because that is what motivates us."

What does this have to do with USB?

"So let's stop calling it a "Parallel Port" . Lets' call it a "High Speed CNC Interface Card""

You're all over the map. Are you supporting Ethernet or Parallel ports? Or just what suits you?

Regards,

Kirk Brown
www.majesticmachinery.com
www.industrycontrols.com

[samco]

I have to agree with torchhead on this one. Everyone asks why emc2 doesn't have some neat usb interface like smoothstepper. Torchhead summed it up. Control. Usb isn't realtime enough to do it. You can tout speed all you want - but it has to be consistant.

I know Emc2 would also do rtnet way before anything usb. (other than non realtime input devices like joysticks and such)

It gets really messy really quick when you start to think about realtime feedrate overrides, rigid tapping... Does smoothstepper do lathe threading yet?

sam

[Torchhead]

You're all over the map. Are you supporting Ethernet or Parallel ports? Or just what suits you?

Just what suits ME! (and works with the controls we sell for DTHC and closed loop spindle speed).

We will not use Ethernet for real time CNC controls any more than we would use USB but it makes sense for other products (like a LCD display pendant we are working on)

What makes me "defensive" is I operate in the real world where most of the CNC guys are not technicians or engineers and they just see: "Blah, blah, blah, USB, Blah, [pretty picture], blah blah" and then when they call, I have to go through all of the things you can't do with the USB solutions. Sometimes I have to tell the guy AFTER he has spent his money on a USB card that he can't use it for what he wants (low cost Digital Torch Height for example).

It appears though, you have things all worked out and don't need my input.

TOM Caudle
www.CandCNC.com

[ktb100]

"It appears though, you have things all worked out and don't need my input. "

More than you know.

Oh, did I mention our boards are currently and SUCCESSFULLY operating plasma torches inside a vacuum chamber where I have to maintain 21 points of I/O in addition to the 4 axis motion while holding the spray to 0.002" thickness on a 8" diameter. It operates 12 hours a day and manufactures bearings for the USMC to which I am alumni. I took the job very seriously. I understand this is not a table. Which I think will be easier.... I am VERY GLAD I took the challenge and did the job before talking to someone so close minded and arrogant. I may have been convinced the earth is flat from such an archaic mind set.

Thanks,

Kirk

[ger21]

Kirk, I think the difference is that you and Tom are working at two different price points. And Tom is letting Mach3 control the Torch height, while you're doing it with external hardware? What Tom is saying, I think, is that Mach3 can NOT control the torch height in software with a USB connection. Correct me if I'm wrong.

[ktb100]

OK,

I can learn to like the Ethernet too. Ethernet based, real time, I/O all good
The USB still does a bang up job but I am impressed with our new board too. We removed screw terminals on the board and put the logic control on one cable, 24Vdc on another one and it seemed to really work well and help keep noise at bay.



Kirk