Messages

8421

General Mach Discussion / Re: configure drive for motors

« on: March 23, 2009, 06:36:02 AM »

Bill is right - it is better to purchase a ready made stepper controller.

The 4 wire bipolar stepper motors when operated in full step mode, in one direction, require current through one set of coils then for the next step current through the next set of coils then for the next step current is reversed through the first set of coils and so on.

The 5 wire unipolar steppers are a lot easier to drive from PICs because one wire is common + and the other wires are grounded in sequence to produce the rotation (there is no current reversal through the coils therefore only one switching transistor is required for each coil).

See the following Wiki.  http://en.wikipedia.org/wiki/Stepper_motor

Tweakie.

8422

General Mach Discussion / Re: OEM codes for buttons, DRO's and LED's

« on: March 23, 2009, 05:35:18 AM »

Thanks Hood for posting the .xls file. It has been most useful.

Tweakie.

8423

Show"N"Tell ( What you have made with your CNC machine.) / Re: Miser engine

« on: March 21, 2009, 03:00:36 PM »

Brilliant Vince. 
I think that letting it run a while will free everything up OK.

Tweakie.

8424

Tangent Corner / 'BIG' CNC

« on: March 20, 2009, 06:54:15 AM »

I spotted this on Flickr - it is just about the biggest CNC I have seen - how about you ?.

Tweakie.

8425

General Mach Discussion / Re: Motor "Sometimes" goes in Wrong Direction while Tuning

« on: March 18, 2009, 01:30:20 PM »

Hi Jamie,

No other suggestions, sorry.

Incidentally do the motors have sufficient torque ?. (can you stop them with little force when they are rotating).

Tweakie.

8426

Show"N"Tell ( Your Machines) / Re: Laser cross hair tool position.

« on: March 18, 2009, 11:39:29 AM »

Thanks Dave.

This is the big advantage of making things for yourself - the boss doesn't moan at you when you don't get it right first time.

Tweakie.

8427

General Mach Discussion / Re: Motor "Sometimes" goes in Wrong Direction while Tuning

« on: March 18, 2009, 07:34:54 AM »

Hi Jamie,

As Hood said earlier have you tried changing the direction signals from active high to active low (or visa versa) ?. This is under Configuration, Ports & Pins, Motor Outputs.

Tweakie.

8428

Show"N"Tell ( Your Machines) / Re: Laser cross hair tool position.

« on: March 18, 2009, 04:39:13 AM »

An update.

The initial mounting method for the polarising filter suffered with a major drawback in so far as it allowed machining dust to enter and settle on top of the filter disc. I have replaced the two alloy spacers with a turned part that should resolve this problem.

Tweakie.

8429

General Mach Discussion / Re: Motor "Sometimes" goes in Wrong Direction while Tuning

« on: March 18, 2009, 03:33:08 AM »

Hi Jamie,

Sorry I just assumed you would know.
A breakout board (BOB) is where the LPT connection from the computer joins with the machine. Some BOB's are 'active' in so far as they incorporate opto isolators and are powered 5 Volts. The Gecko controller already incorporates opto isolators on its inputs and sometimes behaves oddly if active BOB's are used. For Gecko operation a passive BOB is usually used.
Hope this explains what I was getting at and once again sorry for posting a reply that was not fully explained.

Tweakie.

8430

Show"N"Tell ( Your Machines) / Re: novakon milling

« on: March 17, 2009, 12:48:19 PM »

Very very nice machine Marcel.

Tweakie.