Messages

831

SmoothStepper USB / Re: SmoothStepper plugin noise filtering.

« on: June 09, 2009, 01:14:41 PM »

I always recommend optical isolation on any machine, whether it has a SS or not. That good wire management and proper (earth)grounding are your first lines of defense. Don't route noisy stepper or VFD lines in parallel with signal lines like encoders or limit switches (if you can avoid it.) It is generally a good idea to use shielded lines for all you input signals as well. Some machines will use shielded cables for the steppers and other won't. The layout will dictate if you need to shield them or not.

The problem come about if the things your driving also have optical isolation built in (like some Gecko stepper drives) you have to be careful not to 'stack' up the optical isolation.

832

SmoothStepper USB / Re: smoothstepper hangs mach3

« on: June 09, 2009, 12:53:13 PM »

Could the SS perhaps have some additional HW noise filtering that would help? Probably yes. Would it solve all these problems we here about? No.

The first lines of defense when building a machine are proper (earth)grounding and proper isolation (optical or otherwise). Most machine control I/O boards will NOT have optical isolation built in as some of the external boards that are driven (like Geckos) also have optical isolation on their inputs. It is best not to 'stack' them. For example, I refitted an old Bridgeport with a Galil motion control card, the card, the extended I/O board and the breakout board from Galil cost about $2500 and they were not optically isolated. They did offer an isolated version of the breakout board though. I used solid state relays instead, as two Opto22 boards fit in the same place as the old main I/O board did. The solid state relays not only gave me the optical isolation, they also allowed me to switch different voltages directly, both AC and DC.

The problem comes about when folks, who don't know any better, build a machine and don't quite get the wiring neat and tidy and also don't get the grounding done properly. Through in the lack of any form of isolation on most if not all of the I/O and you have a problem. You thorw a SS into the mix (or any USB device) and the USB cable will pick up all that electrical noise causing the main hub in the PC to stop trying to communicate as it says, heck there is a lot of noise here, I can't even hear myself think!". The problem in the noise.

Don't take that the wrong way. I'm not picking on the OP or anyone else. We all start out at the same place, and learn as we go. But, we need to learn what the source of the problem is and improve out own machine building practices too.

833

SmoothStepper USB / Re: SmoothStepper plugin noise filtering.

« on: June 09, 2009, 11:10:46 AM »

I suspect that you have no optical isolation between the SS and your limits?

834

SmoothStepper USB / Re: smoothstepper hangs mach3

« on: June 09, 2009, 11:09:21 AM »

Basically you trapped your SmoothStepper in a box with EVERY noise generating component in your system. The SS circuit board and USB cable can pick up any electrical noise that all those other parts are generating.

You need to protect your SS from electrical noise. The first step in that is to make sure that all your equipment is properly (earth)grounded. The next step is to make sure that all I/O on the SS is optically isolated. Then make sure that your signal wires (limit switches, etc) are not running parallel to your noisy stepper wires. These first steps ally to any system and are not unique to a SS.

Now for the SS: make sure your USB cable is as short as possible and not running along with your stepper wires. Mount your SS outside of the cabinet that all the noisy equipment is in or move it to the PC as has been suggested.

835

SmoothStepper USB / Re: Smootstepper doesn't support backlash compensation??

« on: June 08, 2009, 10:20:30 AM »

The last word by Greg on backlash comp is that Mach will be changing how backlash comp is applied. Currently Mach does backlash comp in the LPT driver itself rather than in the trajectory planner. This means that it is very easy to get the comp settings wrong and try and go too fast while the machine is trying to apply that comp. Mach will be moving this into the trajectory planner, where it belongs, in the near future so it 'should' work on any motion control device.

However the big question is will software backlash comp help? If your doing engraving or very light cuts then you could see some benefit. The problem with trying to do backlash comp on a mill is that the cutting forces will push the table around if there is any backlash. (This even happens on manual mills.) Here is a good explanation of backlash comp: http://liutaiomottola.com/Tools/Backlash.htm .

836

Show"N"Tell ( Your Machines) / Re: My New Router Gantry Build

« on: June 05, 2009, 11:15:44 AM »

When you get it running you can kind of figure out what works best for you by trial and error. Just pick up a couple more timing pulleys that you can swap out with what you have. If you can find some that will give you something in the range of 3:1 and 4:1 it will give you a good idea what works best for you.

Just a thought...

837

Show"N"Tell ( Your Machines) / Re: My New Router Gantry Build

« on: June 05, 2009, 09:11:55 AM »

Very nice looking! I'm so glad to see that your using a belt reduction and have done such a nice job of mounting the serovs. I get SO tired of seegin people just stick a motor directly to the screw and try to compensate by using a huge motor.

Depending on your goal for torque/speed you might find that a bit more gearing is needed to get enough torque at the speeds you'll be cutting at. It all depends on what/how you'll be cutting.

838

Mach3 under Vista / Re: Getting up and running in Vista

« on: June 05, 2009, 09:07:22 AM »

It sounds like some other process (running on the PC) is interfering with Mach's driver.

To use Mach's parallel port driver you have have a very plain-jane installation. Turn all all unneeded services. Uninstall programs like QuickTime and ITunes which have nasty little services that run all the time and check for updates. Some ati-virus software will cause problems too. You'll need to do some investigation as to what is running and if it can be turned off (Google is a great help, search by process name.)

The easy way to do it is to use a SmoothStepper: http://soigeneris.com/Warp9.aspx . It is a motion control board that generates all the step/direction pulses in hardware (making it faster and smoother.) I use one all the time with a Vista laptop that has all sorts of stuff on it. It hooks up via a USB port and talks to Mach directly. It has two parallel port equivalent ports on board as well. You do need the LPH26 to DB25 cable to give you the parallel port style connector though.

Shameless plug I know but the SS makes life SO much easier, no more fighting with the LPT.

839

General Mach Discussion / Re: Hoping to retrofit a CNC mill with Mach3. Where do I start?

« on: June 05, 2009, 08:57:48 AM »

I would not be in a big hurry to trash all the drives unless they just don't work. I refitted an older Bridgeport 308 and left all the drives in place. A Galil card noes nicely to control them.

840

SmoothStepper USB / Re: Installed SS today and having a few problems

« on: June 05, 2009, 08:44:34 AM »

I too have had issues with some built in USB ports. Not on the SS but other devices like hard drives that transfer a lot of data. Glad you got it sorted.