Smooth Stepper USB drive controller

[tjones14]

Has anyone tried the smoothstepper controller?

It looks interesting considering that a parallel port is an addon card to a PC these days and are no longer considered standard. While USB is everywhere.

[markcomp77]

Has anyone tried the smoothstepper controller?

yes... but, SS makes (not only me) problems:
-suspending usb transmission (after about 3h)
-sometimes problems with the computer (crashes) (not often)
-suspending SS (not often)

I was supply SS from usb...
so.. maybe, powering from additional supply of 5Volt will improved operation

[hemsworthlad]

Yes I have a smooth stepper and it works great for me, others have had some problems and in the early days it was worse but now alot of the bugs have been ironed out.
That said it still has some, but very few and these only affect certain types of machine configuration's. I know that backlash comp in Mach doesnt work with SS yet but other than that i dont think there are meny other major issue's.

For ME it does every thing i want and does it well.

The major plus for me is I can use a laptop to control machine, my orginal comp had a very flakey PPort and was all over the place. Now my machine is rock solid and the motors are a lot happier and smoother sounding with a slight increase in speed. Plus because it's very moist and cold here in blighty it's better for the well being of the computer and also means i can work on it in the house were it's warm.
Also the extra IO of the SS are all ways welcome.

So I,m a happy user.

[Torchhead]

Using USB for CNC motion control because "USB is everywhere" is not always a valid argument. It does some things very well (like keyboards, mice, SD card readers, interface to cameras and printers) and others not so well. The information for moving multiple axis lives on a parallel bus. The latency involved in moving the information serially (one bit at a time) and then turning it back into parallel commands causes a realtime disconnect between the control software and the position of a machine (like an echo on the phone line). If all you need to do is move the machine then the effect is not too noticeable. If you need bidirectional information that is time sensitive, then you start to have problems that get difficult to solve. Inputs do not occur in real time and are more random. To solve the problem, More and more of the control functions have to move out to the the remote end of the USB until finally what you have is a realtime controller (kinda like a PC with a parallel port) that uses MACH as just the screen/operator feedback.

Warp9 has done an admirable job in taking USB past a lot of it's limitations but there are inherent issues that will not be as easy to circumvent...if at all.

For about the same amount of money you can go to this Ebay id# 140386443016 and get a refurbed pentium 4 3Ghz with 1G ram, XP pro loaded and with parallel, serial and USB for $139.00. The built in video is good and it runs MACH up to 60,000 pps with no problem.

What is important in our world of CNC is stability. For that reason and others we continue to stay on XP rather than Vista or Windows 7.

TOM caudle
www.CandCNC.com

[zephyr9900]

Tom, per Warp9

The SmoothStepper is powered by a Xilinx FPGA for very high performance. In the current design, the maximum step rate is 4 MHz , but there is no reason why this couldn't be increased to 8 MHz or more if necessary.

The SmoothStepper takes high-level commands from Mach3 (the "user interface") and produces step and direction commands locally to execute the moves. It puts its outputs two two DB25-type ports to be transparent to the user and machine tool, but from my understanding that is it. Where does the SmoothStepper claim to be a serial USB -> parallel converter?

If I'm wrong about that please let me know, because I'm strongly considering a SmoothStepper retrofit for my Tormach mill.

Randy

[hemsworthlad]

Where does the SmoothStepper claim to be a serial USB -> parallel converter?

If I'm wrong about that please let me know, because I'm strongly considering a SmoothStepper retrofit for my Tormach mill.

Randy

I dont think you are wrong, all i can say is it does what it says on the tin.!!

Dont think you will regret buying SS, i certainly dont and know others that dont.
The lathe guys seem to love the SS, i know Hood over on the Mach site as had great improvements with his on both Lathe and mill's.

[Jason3]

Hi Tjones14,

FWIW, I've used a smooth stepper on four of my own CNC machines so far, 3 mills and a lathe. I haven't experienced any fault with any of those. We've also had quite a few clients use them as well, I have replaced one due to failure after a lightning strike and another that may have been fried by bad wiring, or may have been faulty. Warp9 covered that replacement for us. Other than that, there's been no reported problems. As I see it, there are three main reasons I might use one, and two reasons I might not -

For:

1. More speed - if you need to run your servos or steppers faster than Mach3's 100Khz maximum without losing resolution, this is one way to do it. One big tick for the smooth stepper if using a servo for a spindle (either lathe or mill) where you also need C axis capability - you want to retain the highest possible resolution, but you also need to be able to run the servo at speed as well.

2. If you want/need to run Mach3 from a laptop or a PC without a parallel port.

3. More IO without adding another parallel port to your PC.

Against:

1. Another component to buy, another component that can fail.

2. Feed hold can be quite slow to respond (due to the buffer, I expect). You can always use the E-stop, of course - but sometimes you might not want to risk losing position but you do need the machine to stop NOW. Overloaded spindle, clogged cutter, work coming loose? That sort of thing.

There's undoubtedly other reasons for and against, hopefully other users will chime in too. For either of the first two reasons to use one, I would happily do so. If I didn't need the speed and had a parallel port, then I would save the money.

Best regards,

Jason