Messages

861

SmoothStepper USB / Re: Which BOB for the smooth stepper

« on: May 16, 2009, 03:07:36 PM »

I recommend optical isolation whether your using a SS or not. It is simply the best way to prevent most of the little gremlins from getting into your controls. Some of the Gecko drives have the Step/Direction lines optically isolated at the drive, the G540 has built in optical isolation on all inputs/outputs. So, in those cases your set. 

862

SmoothStepper USB / Re: Which BOB for the smooth stepper

« on: May 16, 2009, 12:51:58 PM »

Judging by the photos that board is not opto-isolated 

It has a few ICs that act as buffers. The LPT can't sink or source much current, by running through a buffer gate you get the same logic signal but greater fan-out (stringer signal).

863

General Mach Discussion / Re: accuracy issue

« on: May 12, 2009, 11:55:08 AM »

Glad you got it sorted. 

864

General Mach Discussion / Re: accuracy issue

« on: May 12, 2009, 11:21:06 AM »

The first thing to try is cutting your velocity and acceleration in half. If this works well it would be a clue that perhaps your initial settings were on the borderline of being too fast. Also check that mechanically things on that axis are in good shape. Nothing loose or binding etc. If you use the same type of driver for each axis you can swap drivers to to see if the problem follows the driver or axis.

Laptops can cause problems, but I would expect you to see the problem on every axis.

865

General Mach Discussion / Re: Any way I can get Mach to send me an email when it's finished?

« on: May 12, 2009, 09:29:38 AM »

I'm not sure under the Cypress flavor of VB that mach uses. It can call other libraries though. I would do some googling on sending email in VB script or VB 6. That should be pretty close. I have some code around somewhere for VB.NET that I used for an introductory class on VB. If I can find it I'll post it.

I just found lots of info searching for 'VBscript send email', here is one:
http://www.activexperts.com/activmonitor/windowsmanagement/adminscripts/enterprise/mail/

866

General Mach Discussion / Re: Mach 3 won't run under certain Laptop

« on: May 12, 2009, 09:26:33 AM »

Laptops are notorious for not running Mach properly. All the power saving features in a laptop prevent the precise timing that mach needs to operate properly. There is a document on the forum somewhere about optimizing a laptop for use with Mach. That may help but in my experience it still does not work as good as a desktop machine. If you set on using a laptop then I think your best bet is to use a SmoothStepper: http://soigeneris.com/Warp9.aspx . The SmoothStepper handles generating the precise timing pulses needed by the stepper motors (better than the LPT can) and lets Mach worry about trajectory planning and the UI.

867

SmoothStepper USB / Re: SmoothStepper now available in Australia

« on: May 10, 2009, 04:25:43 PM »

Jason, there could be a few different things going on. The 'clunking' sound you are hearing is a really good sign that your not getting a good, jitter free pulse stream. Laptops are typically not a good choice as a control computer as all the power saving stuff they put in them interferes with processor speed. There are a number of tricks you can try on a laptop but in my experience the results are usually not very good. I always try to sell folks a SmoothStepper with the systems I sell to prevent them having problems trying to get things running smoothly with a parallel port. On a laptop I would say that a SmoothStepper is mandatory.

I'm not sure how your system is set up (power supply type, voltage, stepper wiring, etc) and what type of speeds your trying to run. The HobbyCNC board is what I would refer to as an 'old school' design. Nothing wrong with it in general, but you just can't get the same performance as with a more modern design. Drivers like the Gecko have midband resonance compensation (adjustable), morphing microstepping (go from 10x microstepping to full steps as you increase the velocity), etc.

With your laptop I would suggest a SmoothStepper, if your in Oz then Peter is your guy. If your in the States or elsewhere I could set you up with one.

868

General Mach Discussion / Re: my first project

« on: May 08, 2009, 10:38:52 AM »

the servos will start to spin, then speed up out of control.

Sounds like the servo drives are not seeing the encoders...If you can control the servos with the drive mfg software then it could be a configuration problem with Mach/SS.

I have an E-stop located at each corner of my machine.  When the button is pressed, nothing happens.

Your E-stop should remove power from the drives by breaking the AC connection to the drive power supply. The E-Stop input into the BOB and mach is just to let them know what is going on. You cannot depend on your controller to stop the drives.

The last question for now is can I or should I connect my over travel limit switches directly to my BOB or can I connect them to the Modbus I/O board?

Limit switches should go through the BOB and should wind up at the VSD-E too. Never, ever, ever, ever try to run a motion control input or E-Stop through modbus.

869

General Mach Discussion / Re: Need Documentation

« on: May 08, 2009, 10:32:24 AM »

Have you done any seraching yourself??

870

General Mach Discussion / Re: Can two 36v power supplies be used in series to get 72v?

« on: May 06, 2009, 01:11:17 PM »

I have been using the MeanWell S-320-48 for smaller machine but I was testing a MeanWell SP-320-48 yesterday as it has a universal input, and power factor correction and is CE approved. It was solid as a rock. One hour at 80-85% load and the built in fan kept the case cool. I could not overload it with the types of steppers I would use on such a system so I directly shorted the output. The supply shut right off and started again when the short was removed (just like the data sheet says).

A good quality switching supply with proper overload protection is hard to kill.