FAQ USS (USB SmoothStepper)

 Please remember that the USS only works with Mach3 and NOT Mach4.


My USS has its connection drop out now and then, help!

This is most likely your problem if you are seeing a message that looks something like this:

USB Error

  1. Make sure your USB cable is firmly connected.  The cable could be loose, and movement could be causing your issue.
  2. Make sure that you are not using one of those little wind up USB cables.  They cause lots of noise and data errors.
  3. Make sure that there are no USB drives attached to your PC.  Never run GCode from a USB stick or USB drive.
  4. Try a different normal USB cable.  The one you are using might be damaged.  If you need one, we sell them here.
  5. Make sure you are connected directly to your PC and not through a USB HUB or a monitor's USB Hub.  Some HUBs are flaky and can cause packet drops.
  6. Try a different USB port on your PC.  I have seen this fix problems several times.  It could be because there are fewer USB devices on the new port, or it has less noise on it inside the PC.
  7. Disconnect as many other USB devices as possible from your computer.  One of them could be malfunctioning.
  8. How long is your USB cable to the USS? The shorter the cable length, the less noise it can pick up.  This will help if you are getting weird or intermittent dropouts.
  9. Make sure the USB cable does not run alongside from any high voltage or high current wires or other noisy wires. If the USB cable has to cross other wires, make sure it crosses at a 90 degree angle.
  10. Disable Selective Suspend.
  11. In Device Manager, Uninstall the USB SmoothStepper and check the box to delete the drivers.  Then download a new copy of the USB drivers and scan for hardware changes.  When your USS is found again, install the drivers that you just downloaded.

Delete Drivers

Scan for Hardware


Other points to consider:

  1. How are you powering your USS (USB SmoothStepper)?  Poor or noisy voltage can cause the USB connection to drop out.  We have a section on USS power supplies here.
  2. How are you powering your Break Out Board?  Poor or noisy voltage can cause the USB connection to drop out.  We have a section on USS power supplies here.
  3. How much current is your BOB consuming?   If the BOB is pulling power from your USS, it could be taking too much power and causing the USB issues you are seeing.
  4. Can you try to turn off your dust collection system and see if you can do an air cut?  Can you ground your table and axes to ground and do an air cut?  Forum thread that had this problem.

Another good step is to turn off the Windows Power Saving options for your internal (on motherboard USB hubs).  Go into Device Manager and then for all of your USB Root Hubs and Generic USB hubs. Uncheck the "Allow computer to turn off this device to save power" option.  Why do we say all?  Because it is slightly harder to determine which hub your USS is plugged into, and if you ever change connection locations, it may become associated with another Hub.

  1. Open the device manager by pressing the “WINDOWS” key and the “R” key at the same time. 
  2. When the "Run" box opens up, type in "devmgmt.msc".
  3. For each USB Root Hub and Generic USB hub, uncheck the "Allow computer to turn off this device to save power" option.


USB Error


Finally some people have the best results by removing their USB cable shielding.  I would try all of the other steps first.  You would want to seal the cut area with heat shrink tubing or at a minimum electrical tape after the fact. That would provide structural support and strain relief.











Disable the Selective Suspend Setting

The Selective Suspend setting allows Windows to decide if it wants to turn off your USS during the middle of a job.  If it decides to this, you will lose connection to your USS and your job will be ruined.  This is mrmfwilson's guide to the problem as shown here.

1. In Windows 10 or 7, bring up the start bar and type; Edit Power Plan. Select the entry from the list. This will open the "Edit Plan Settings" window.
2. Select the "Change advanced power settings" in blue at the bottom of the window. A Power Options window will appear.
3. Choose the power option that is active in the top selection box. I use the High Performance.
4. From the list of options look for the USB Settings. Expand that window.
5.There will be a USB selective suspend setting option.
6. Expand that option.
7.It will show the Setting and that it is Enabled.
8. Disable the setting.
Close all the windows. Make sure the plan you changed is the active plan.

The only thing that I did not do was in the device manager portion of the article and un-check the box to turn off the device during power save. This didn't affect me probably because I am using the High Performance option that doesn't let anything turn off power. If you are using the Balanced plan you will need to make this change. I recommend the High Performance profile. What do you have to loose? Your machine is dedicated to the machine.


Authentication Attempts Message

Occasionally, this message will pop up due to a glitch in communications while the SmoothStepper is initializing. We have modified the ESS to correct for this (in most cases), and we will be modifying the USS in the near future to use the same fix.

The first time you see this message:

  • Close Mach
  • Power off your SmoothStepper, and wait 5 seconds
  • Power the SmoothStepper
  • Start Mach again

It will usually work just fine and you will probably never see this message again.

If your counter for tries remaining gets below 6, then you need to talk with us, and we have another fix.


Authentication Attempts


Windows USB Driver Issues

If your Window's Device Manager won't recognize the USS anymore, but it used to, it is very possible that the Window's driver for it became corrupted.   

Watch this video. Stop at 1:04, and right click on the USB device the SmoothStepper is showing up as. In the menu that opens, click on "Uninstall", and then check the little box that says to delete the driver for this device.




After that:
1) Remove the USS from your PC
2) Reboot your PC
3) Follow the steps in the video from the beginning and do what it shows.



If that didn't work , you may need to force Windows to show drivers for all devices that are not currently connected.

1) Start a cmd prompt as an administrator and type the following:

  • set devmgr_show_nonpresent_devices=1
  • start devmgmt.mscset devmgr_show_nonpresent_devices=1
  • start devmgmt.msc

2) Uninstall the USS, and delete the driver software for the device.

3) Remove the USS from your PC

4) Reboot your PC

5) Follow the steps in the video from the beginning and do what it shows.



If that didn't work, try this:

Run this program from FTDI (be sure to unplug the SmoothStepper first):

There is a command-line version and a graphical version, run the graphical. Here is the graphical version Read Me.

You will need to enter "0403" for the Vendor ID, and "A650" for the Product ID (don't include the quotes, and be sure that the "A" in "A650" is capitalized).

Click Add.

Then click "Remove Devices" and it will remove every instance of a SmoothStepper from your system. Plug in the SmoothStepper and you should be able to install it properly.

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