Messages

6271

General Mach Discussion / Re: Caps on inputs

« on: August 04, 2011, 12:52:40 PM »

Well, we switched the caps to go from the input pins to ground and the test pattern worked perfect!! but...then a longer pattern flipped out. We definitely have interference issues. Gonna rewire with shielded cable - is this stuff any good or is there some that would be better? http://homeavcables.com/22108.html

You would be better using a cable which has a braided shield (more surface area) the foil stuff is OK but far from Ideal.

Tweakie.

6272

General Mach Discussion / Re: G31 Probe problem

« on: August 04, 2011, 09:00:47 AM »

Thanks Ian.

Tweakie.

6273

General Mach Discussion / Re: mach3 estop external switch issue

« on: August 04, 2011, 07:27:17 AM »

 

Tweakie.

6274

Tangent Corner / Interesting 2 ?

« on: August 04, 2011, 05:30:50 AM »

This looks like an easy way to interface an "add-on, high speed engraving spindle". (as featured in Digital Machinist)  http://www.logicnc.com/rcnc.html

Tweakie.

6275

General Mach Discussion / Re: mach3 estop external switch issue

« on: August 04, 2011, 03:33:54 AM »

Hi Jas,

I understand what you are trying to achieve but safety must always take priority and as Terry has already said this is a dangerous way to go.

Far greater minds than ours have decided this is the way it will be and for good reason and what you are attempting could perhaps be considered as the equivalent to defeating a safety switch or machine interlock.

We must all pay strict attention to safety if we are to "live to machine another day" 

Tweakie.

(I think I must have been a safety officer in a previous life) 

6276

Show"N"Tell ( Your Machines) / Re: The Laser Project.

« on: August 04, 2011, 02:37:26 AM »

Hi naPS,

That's great news that you have it all running OK so where are these pictures then ?? 

Tweakie.

6277

General Mach Discussion / Re: G31 Probe problem

« on: August 04, 2011, 02:30:40 AM »

Hi Guys,

So, should we be using the Sleep() command within the while...wend or not ??

Tweakie.

6278

General Mach Discussion / Re: New people welcome !! Come in here and introduce your self!

« on: August 04, 2011, 02:14:08 AM »

I wish if a day was mach's day in a year, when all the cnc jerks could enjoy some beer together somewhere (some could have scotch also)

jasminder singh

The Beer would suit me just fine 

Welcome to the forum guys  ( I think Tricky Dicky must be on holiday at the moment ).

Tweakie.

6279

General Mach Discussion / Re: Caps on inputs

« on: August 04, 2011, 02:07:08 AM »

I haven't had any noise problem with my CNC machine, but I used to race RC cars, and we put caps from the positive motor input to the motor can, from the negative motor input to the motor can, and from the positive input across to the negative input.  (strictly DC battery power to the motor)

This completely did away with noise from the motor, don't know enough about steppers and driver boards to know if that would work or not.

Jim,

You are quite right about the brush type RC car motors but Stepper Motors are different in some quite important ways. During operation the bipolar type motors have current reversal through their windings and although the magnetic field has to collapse and re-establish - to ensure that steps are not missed, this usually happens within 2nS. Fitting any capacitors to the motors will compromise this timing and could totally destroy performance - It may also cause damage to the motor driver circuit.

(Bit of a co-incidence really, but yesterday I was measuring current reversal times in 20 differently constructed coil types to establish the so called 'point of stall' when driving solenoids and relays from bipolar stepper motor drive circuits).

Tweakie.

6280

General Mach Discussion / Re: Axis reversed??

« on: August 03, 2011, 11:45:54 AM »

Hi Rikk,

I was going to tell you that but I thought Hood would have got there before I finished typing 
(perhaps he has taken the afternoon off and gone fishing ?)

Tweakie.