Messages

501

SmoothStepper USB / Re: Smooth Stepper and Plasma

« on: October 21, 2010, 10:47:05 PM »

The cutting table should be tied to the ground rod as well. If you have a HF start you need to shield the torch leads too.

502

SmoothStepper USB / Re: How to use closed loop spindle rpm with SS

« on: October 21, 2010, 08:39:36 PM »

I think maybe you have configuration problems. I have had the G540 VFD out hooked up to a KBIC and I seem to recall it was not more than 100 RPM off all along the scale. Do you have the tach sensor on the motor or spindle?

503

SmoothStepper USB / Re: How to use closed loop spindle rpm with SS

« on: October 21, 2010, 12:46:46 PM »

Actaully, DC motors ARE quite linear in speed w.r.t. input voltage. Speed controllers and/or PWM to voltage circuits are not linear many times though. If you set it up open circuit does mach's PWM output change in response to your commanded speed?

504

SmoothStepper USB / Re: How to use closed loop spindle rpm with SS

« on: October 21, 2010, 12:05:46 PM »

OK, that is not closed loop either It is just PWM output.

There was a post a few weeks ago here about getting PWM running properly. I'll see if I can find it later and link to it here.

Here is the link: http://www.cjh.com.au/PWM%20Spindle%20Control%20using%20Mach3.pdf

505

General Mach Discussion / Re: Problem with smoothstepper in a new installation

« on: October 21, 2010, 10:50:16 AM »

Please see: http://www.soigeneris.com/Document/Installing_and_Configuring_the_SmoothStepper.pdf . Also, what to you mean by 'cleaned pc'? It is much better to start out with a fresh, NON-ACPI, Windows installation. Then follow the tips in the document above. Also, posting this in the SmoothStepper section of this forum might generate more responses.

Perhaps a moderator will move it to the SS section of the forum?

506

SmoothStepper USB / Re: How to use closed loop spindle rpm with SS

« on: October 21, 2010, 10:47:19 AM »

I suspect you really don't want closed loop operation. What you are likely after is Mach syncing with the spindle speed. Look at the Spindle tab in Ports&Pins.

507

SmoothStepper USB / Re: Smooth Stepper and Plasma

« on: October 21, 2010, 10:38:12 AM »

I can cure the mouse problem by going back to a non-usb mouse.

No, you are masking the symptom; you still have a noise problem and you will have random PC issues because of it. Fixing the source of the noise issues is the only way to 'cure' it.

508

SmoothStepper USB / Re: Smooth Stepper and Plasma

« on: October 18, 2010, 10:00:59 AM »

Plasma systems can be some of the hardest systems to get/keep working properly. Even the big name high $$$ controls have trouble with the noise generated by plasma power supplies.

The first rule of thumb is good grounding. A ground rod driven by the machine is next to useless as it is being driven in bone dry ground. A single ground rod may also not be enough. A really simple test is to drive an 8' ground rod 4' or so away from your building and connect a 100W incandescent light bulb between the ground rod and an 110V AC neutral. If you have a good ground the bulb will not light. I have seen a few 'extreme' cases over the years where we had to go to great lengths to get a good ground. In one case the company had to drill a 20'~30' deep hole beside the building, fill it with dolomite (sp?) and run a ground rod all the way down. The second case was not as bad and just required three ground rods driven about 4' apart and all tied together. The cutting table and plasma power supply were both bonded to this earth ground. Make sure your wiring is properly earth grounded, remember that DC Common is not the same thing as earth ground.

Once you have a good ground the next step is to properly isolate the controls from the plasma noise. You must use isolation between the plasma power supply and the controls. Be very careful with how torch leads are routed. We used to wrap the leads in a wire mesh shield and then cover that with a leather cover (for wear protection). This helps keep the noise from radiating out of the torch leads and into other things.

Other things to try are to use an external power supply to power the SmoothStepper (or a powered USB hub). Some folks have also reported that bonding the SS 'ground' (DC Common) to the PC case did the trick.

509

SmoothStepper USB / Re: Smoothstepper problem when spindle is on

« on: October 15, 2010, 09:06:47 AM »

I have installed the smooth stepper inside mi PC with the connections on back as regular PLT port.

I have grounded the Smooth stepper card to PC chassis and  it´s working fine now.

I've been pondering this for a few days now. I initially missed that the SS was installed in the PC. Since the length of the USB should not be an issue with this type of installation it makes me wonder 'why' bonding the SS ground plane to the case ground helps. The PC power supply is tied to the case via the power supply case but some switch type supplies will use a small cap or cap/resistor in series rather than a direct bonding which could cause the DC Common to float a bit above Earth ground.

Anyhow I'm glad it works. I'll have to do a few more tests on my system to try and figure out why.

510

SmoothStepper USB / Re: Smoothstepper problem when spindle is on

« on: October 12, 2010, 11:09:26 AM »

Try grounding the Smooth Stepper GND pin (on the external power supply header) to the PC case.

A sure way to create a ground loop. Never do so unless it is the only thing that seems to work.

The inverter is installed together with gekos, breakout board inside second PC cabinet.

Installing a VFD in close proximity to other controls is just asking for problems. They are VERY, VERY noisy. Many commercial machines will place a VFD in a separate control cabinet to mitigate such problems. Using proper isolation, wiring and grounding techniques will help but sometimes relocating the VFD is the only option.