DeskCNC

[CNCadmin]

I used Deskcnc awhile a go has is anyone using it now?

[dcd121]

Yes, for over a year it has created g code and controlled my machine with good results.

[Kookaburra]

I use it with all our controllers. A proven great package. We are currently working with the developer at the moment, watch this space, great things to come.

[phrog]

I just purchased DeskCNC with controller and digitizer for $575.00 after looking at at the demo for some time, and looking at several other packages. I though this provided the most for the money. One thing of note to anyone getting into this for the first time, if you wish to run your machine from Windows you will need a control package that provides an external pulse generator, to achive good performance. I have tried several packages in both Windows, and DOS, and wrote a couple Windows apps myself (Industrial Software Developer by trade) to try and overcome this by placing the pulse generator code in a protected run-time kernal below Windows, and experienced performance in line with DOS based packages. I am hoping that DeskCNC will cure this problem, and if not, they include a nifty programming API to use with the controller board, and I may take a stab at some new software to control it.

[MikeT]

I've been using DeskCNC for a little over a year now. Have had absolutely NO problems with it.
Most reliable piece of software I've purchased.
Mike

[imserv]

IMService is the US based master distributor for DeskCNC. We will have 4 machines at NAMES April 24-25, near Detroit, MI. All 4 running with servos and DeskCNC.

Sherline mill running 3D probe surface scans
Sherline Lathe
Desktop router (17 x 17)
Sherline mill with new belt drive servos

If you are in the area, it will be a good chance to see DeskCNC in action. "Mr. Carl" (the author of all the Deskam and Deskcnc software programs) himself will be present.

Fred Smith - IMService
http://www.cadcamcadcam.com

[Rhodan]

Let me see if I understand how DeskCNC works.

Unlike other software such as KCam and Mach2, DeskCNC requires an interpreter board (DeskCNC controller). Instead of bit-banging the parallel port it sends move commands to the interpreter board through the serial port. The interpreter board generates all the signals needed for (your) axis drivers. This avoids the rather nasty Windows PP API which doesn't give software control over timing of the parallel port. The result is faster and smoother motion than is normally possibly under windows.

One thing I'm not grasping. The web page says that it requires the same pitch screws on X and Y to do circular interpolation. Since it knows how many steps per inch each axis is, I can't see it having troubles doing circles. This only leaves me simply not understanding what is meant by "Circular Interpolation". So, what does this mean and what are the implications should you not have identical pitches on X and Y?

[imserv]

"Unlike other software such as KCam and Mach2, DeskCNC requires an interpreter board (DeskCNC controller). "

If you think of it as a breakout board, things may come into perspective when comparing to parallel port controllers. It is however an intelligent breakout board with direct e-stop, feed hold, cycle start, and probe/limit inputs, and output relay control signals for spindle speed and direction and flood and/or mist coolant. Because the hardware control is on the controller chip and not tied to the parallel port, it is also possible to use a USB to serial adaptor.

"The result is faster and smoother motion than is normally possibly under windows."

That is correct. About 45,000 smooth steps per second on a "dumpster grade", Windows 98 (or later) computer, which is also faster than many DOS controllers can meet. All 4 axes can be pulsed at this rate at the same time.

"what is meant by "Circular Interpolation". So, what does this mean and what are the implications should you not have identical pitches on X and Y?"

With DeskCNC, circular and linear interpolation are implemented within the controller in hardware. Circular interpolation requires that both axes have the same step ratios. If you want to cut an arc and you don't have the same ratios, you are attempting to do elliptical interpolation. Elliptical interpolation is not implemented in hardware, but it IS implemented in software. For most users this will be a distinction without a difference.

However at extremely high feedrates (and greater than 300 motion blocks per second), the software interpolation throughput may limit the top speed. An arc takes only one motion block whereas an ellipse can take many. Hence a significant speed increase if both axes have the same ratios and arcs are used in the G-code.


Fred Smith - IMService

http://www.cadcamcadcam.com

[Rhodan]

Now I get the circular interpolation part. Its not that it *cant* do it if the axis pitches aren't the same, it just means that it'll take CPU power to calculate the ever changing slope of the eliptical path required to cut that circle. As long as your computer is fast enough to do the calculations within the time span required to complete a command, you won't notice anything. If its not fast enough, the controller will have to twiddle its electrons for a bit, waiting for the new information to be calculated and sent.

Oh and yes, I was trying to make out what all the screw connectors were on the controller. I think the ones on the left side of the picture are home switch inputs, the rest I couldn't really make out.

I'd like to suggest that the desciption of the controller board could do with some expansion. Just looking at the description I didn't realize that it was really a complete breakout board with limits, estop, etc. To a noob it seemed more like a copy protection dongle (incorrect assumption of course). I've only just recently become aware of the difficulties with bit-banging the parallel port through windows. I Guess its one of those things that "everyone knows so why bother explaining?" things we all fall into.

At $100 it seemed like a horribly expensive copy protection dongle. Now that I know what it really is, $100 seems quite reasonable to me. Hell, I spent $60 putting together a urinal flush timer for work - and believe me it was NOT complex.

So far DeskCNC is the front runner for me. Mach2 looks damned good too and I like the price but, I want to do mostly 2.5D stuff (PCBs, front panels, etc) and DeskCNC seems to be the least hassle on my part. DeskPCB looked OK too but who knows, might want to move up to a "real" milling machine sometime and whack some metal around.

[IJ.]

I'm using DeskCNC for my upcoming retrofit on a knee mill ad had a chance to play with it at CNC Teknix on one of their shop machines while I was there picking up my controller/servo motors and PSU.

For someone that has never touched a PC based CNC I found the implication/application amazing and it's so easy to do what for me on manual machines is near impossible (not enough hands)!

I also bought their "digitising probe" and am looking forward to playing with it !

[imserv]

Originally posted by Rhodan Oh and yes, I was trying to make out what all the screw connectors were on the controller. I think the ones on the left side of the picture are home switch inputs, the rest I couldn't really make out.

Here is a diagram that shows most of the connections.
http://www.imsrv.com/deskcnc/OtherConnections.htm

All the functionality of DeskPCB is included in DeskCNC.

Fred Smith - IMService
http://www.cadcamcadcam.com

[Rhodan]

Originally posted by imserv Here is a diagram that shows most of the connections. http://www.imsrv.com/deskcnc/OtherConnections.htm All the functionality of DeskPCB is included in DeskCNC. Fred Smith - IMService http://www.cadcamcadcam.com

I missed that one - I even looked at the flow chart link right beside it too heh. Definately a lot of functionality in that little board - going to save me a LOT of work.

Check your order desk - just put mine in