RE: RE: [mach1mach2cnc] USB Smoothstepper Grounds?
Thanks guys. I bought some line filters this morning, and it has fixed the problem so far. I'm still in the process of assembling all the bits into 1 single box so everything is kinda hodge podge wiring just to see if it all works. Chicken and egg story. I need the mill going to cut the panels for the control box! Anyway with some quick testing it seems to have solved the problem. Hopefully once it's all built properly and running for some time it will still be good.
---In firstname.lastname@example.org, <email@example.com> wrote:
>>Anyway my problem is that when I turn on my spindle the system resets and I get an error saying "Error returned from USB function FT_Write" plus some other info.As the Mythbusters would say, “Well there’s your problem!”
Any motor will produce a lot of electrical noise when it is turned on or off. That noise is getting back into your PC and SmoothStepper and killing the USB communications. The ‘problem’ is the electrical noise the motor generates, the ‘symptom’ is the loss of communication. It is always best to try and start sorting out a noise problem by getting rid of the noise at the source.
For small mills like a Taig I like to mount a line filter up close to the spindle motor: http://www.soigeneris.com/line_filter_and_switch_box-details.aspx (my website), for other machines this is not as easy to do but the filter itself: http://www.soigeneris.com/line_filter_kit-details.aspx can be placed anywhere but as close to the source as possible is better. You also want to make sure that your USB cable is not bundled up with the stepper cables, spindle motor power cord or other high voltage/noisy signals.
The next step is to keep noise out of your PC and controls. I found that a spike of noise on the AC feeding my PC would show up on the 5V USB bus to the extent that the 5V would go negative briefly. This stopped a USB SmoothStepper, and USB keyboard/mouse as well. I now have a line filter box that my PC and control box plug into, these keeps the majority of external electrical noise out.
Using an external power supply for the SmoothStepper is also a very good idea: http://www.soigeneris.com/meanwell_ps_05_power_supplies-details.aspx , an external supply will not let a blip on the USB bus 5V have as much of an impact on the SmoothStepper.
From: firstname.lastname@example.org [mailto:email@example.com] On Behalf Of mutski47@...
Sent: Thursday, September 26, 2013 2:25 AM
Subject: [mach1mach2cnc] USB Smoothstepper Grounds?
I've just upgraded my motor drives to a USB Smoothstepper and a Gecko G540. It has been fairly painless getting my motors to move, and the limit switches and e-stop etc all working. It's amazing the difference in speed between the G540 and my old cheap Chinese drives. The Gecko should be called a lightning bolt or something!
Anyway my problem is that when I turn on my spindle the system resets and I get an error saying "Error returned from USB function FT_Write" plus some other info. I did a Google search and it there's some people saying it's caused by a ground loop issue (http://mindslikemachines.com/cnc/computer-numerical-control/the-cnc-control-system/the-smoothstepper/) for example. This guy is suggesting to isolate USB ground and Smoothstepper ground. Does anyone have any thoughts on this? Should I be isolating grounds, or actually joining them all together? I assume if if I isolate USB ground, then I would need an external 5V power supply (currently still running of USB 5V). I ask the pro's for their advise on this.
Cheers - Matt
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