Messages

6301

General Mach Discussion / Re: Stepper driver chips

« on: January 25, 2011, 11:05:20 AM »

Ray,

The Xylotex boards, particularly within their enclosures are not exactly renown for their reliability. Whether this is due to the chip or the design of the board would be a difficult call but I get your point - the more robust the chip the better.

Tweakie.

6302

General Mach Discussion / Re: Stepper driver chips

« on: January 25, 2011, 04:26:48 AM »

Tony,

Personally, I would rather buy a ready made, multi-axis, controller board but there is nothing wrong with building your own if you can (certainly learn a lot more by building your own).
Here are a few websites you may like to check out and as one leads to more there could be a lot of browsing here.

http://www.fromorbit.com/projects/picstep/index.php
http://www.edingcnc.com/index.php?pagina=8_download
http://www.embeddedtronics.com/
http://www.pminmo.com/
http://store.qkits.com/moreinfo.cfm/QK179

Good fortune with your project,

Tweakie.

6303

General Mach Discussion / Re: Stepper driver chips

« on: January 25, 2011, 02:30:01 AM »

Ray,

You can blow up anything if you operate it outside the manufacturers specification. Blowing up several Alegro's could be classed as careless. 

Tweakie.

6304

Show"N"Tell ( What you have made with your CNC machine.) / Re: Rack and Pinion Reduction Drives

« on: January 25, 2011, 02:25:38 AM »

Very nice work Michael.
How are you getting the tension on the drive belt ?

Tweakie.

6305

General Mach Discussion / Re: Power Supply +Se amd -Se sigal

« on: January 24, 2011, 12:12:22 PM »

Tweakie,

Thanks for your explanation.  I would assume then this is only useful if a voltage drop is anticipated. If not then one could just jump the +5V with the +Se and the -5V with the -Se terminals.  If this is incorrect please let me know about it.

Jorge

That's exactly what I would do.

Tweakie.

6306

General Mach Discussion / Re: Stepper driver chips

« on: January 24, 2011, 12:10:12 PM »

Hi Tony,

Although they both perform a similar function they are not interchangeable. The 3717 is essentially a single phase device and you would need two chips to drive one bipolar motor. Although they are OK for printers and scanners etc neither are really suitable for CNC use because the drive current is just not sufficient. (Most bipolar stepper motors require a minimum 24 Volts at 2 Amps to provide sufficient torque to drive a CNC). There are better Stepper Motor chips available – take a look at the Alegro range for starters.  http://www.allegromicro.com/en/Products/Categories/ICs/motor.asp

Tweakie.

6307

General Mach Discussion / Re: Power Supply +Se amd -Se sigal

« on: January 24, 2011, 11:43:56 AM »

Jorge,

It is usual on the quality, adjustable, bench power supplies to have Sense (Se) terminals which are link connected to the main terminals to complete the feedback loop for output regulation.

Tweakie.

6308

General Mach Discussion / Re: spindle speed control

« on: January 24, 2011, 06:19:10 AM »

Thanks Larry, I would dearly like to understand quilting machines and their setups. (although I read up as much as I can I think I will probably have to obtain / build a quilting machine before I finally get a grip).

Tweakie.

6309

General Mach Discussion / Re: spindle speed control

« on: January 23, 2011, 12:27:40 PM »

I have read this 10 times Larry and I still don't understand exactly what you are trying to achieve. 

Just as an example machines such as 3D printers often drive the material feed drums but because the material requirement or motion is not constant they use a micro switch or other sensor to check the position of a loop in the material then, when necessary, operate the drum drive a fixed amount then return to standby for the sensor to provide the next signal.
This idea could be made to drive both ways, is this of any use ?

Tweakie.

6310

General Mach Discussion / Re: Enlargement problem

« on: January 23, 2011, 04:55:17 AM »

Lou,

There are a few good tips for correctly setting up the 'steps per' in the 'members docs' area in particular you can download this calculator written by Al Lenz from here http://www.machsupport.com/forum/index.php/topic,16315.0.html.

Hope this helps,

Tweakie.