Messages

8931

General Mach Discussion / Re: Progressive Move Error with X and Y

« on: August 29, 2008, 02:49:35 AM »

A word of warning - when wiring direct and bypassing the BoB be aware of the fragility of the LPT port. It only takes a few mA in the wrong direction to destroy the port completely and possibly the mother board as well.

8932

Mach3 and G-Rex / Re: g100 questions please help!!!!

« on: August 27, 2008, 05:00:15 AM »

With regard to your Dremel connection - I think this is a risky venture as any possible fault within the Dremel itself could raise the electrical potential of the front bearing and shaft to an unacceptable level as far as the other electronics you are connecting it to are concerned. Connecting the bearing directly to earth potential may be OK but not to the negative of the BoB.

8933

Show"N"Tell ( What you have made with your CNC machine.) / Re: GEAR CUTTING TOOL - POST#2

« on: August 25, 2008, 01:49:41 AM »

A bit off topic but I would love one of those R/C draglines.

8934

General Mach Discussion / Re: Progressive Move Error with X and Y

« on: August 19, 2008, 01:55:50 AM »

Just a 'by the way' thing but if we profile cut a shape the number of +X steps equals the number of -X steps and the number of  +Y steps equals the number of -Y steps (this applies to any object where the toolpath starts and finishes in the same place). If steps are,say, gained at random then a 'gained step' when traveling in the +X direction automatically becomes a 'lost step' when traveling in the -X direction (and the same will apply to the Y axis) then gained steps may well cancel each other out exactly and no error will be observed. The same argument will not apply to lost steps, which are created somewhat differently.
All though it is a (very) long shot it is possible this could be cause of your problems.

8935

SmoothStepper USB / Re: Got Smoothstepper 1.2

« on: August 16, 2008, 08:20:42 AM »

Good point Hood !

btw. If Mario keeps that up he could go blind.

8936

SmoothStepper USB / Re: Got Smoothstepper 1.2

« on: August 16, 2008, 05:09:16 AM »

1) The existing Mach setup should work OK 'as is' for the initial tests.

2) As the manual says:-
    3 Resistors, used for termination at the differential receivers. These resistors are provided for your
    convenience if you choose to terminate a differential encoder. The resistors may be attached to
    the wires on the screw terminals. They may also be soldered to the circuit board if you are
    qualified to do so. The resistors have a value of 121 ohms. This may or may not match the
    impedance of your cable. That is one reason they are not pre-installed.

    If you are not installing encoders just forget about the resistors.

3) If it has USB then it should work just fine with your notebook.

8937

General Mach Discussion / Re: Progressive Move Error with X and Y

« on: August 14, 2008, 10:28:37 AM »

Hi Carl,

I have been following this thread with interest, as have many others, and I would like to add my comments regarding progressive errors.

1) Errors are caused by 'gained' or 'lost' steps.
2) Lost steps are usually caused by the stepper's inability to drive the load presented (speed, torque,friction etc.).
3) Gained steps are usually caused by noise spikes occurring on the 0 Volt side of the step pulse train from Mach on the LPT connection.

If you are going to replace your breakout board then try using 74LS14 schmitt's in series with the step inputs (direction inputs will be ok straight through). One schmitt is ok if you change the config, ports & pins, motor outputs, to 'step low active uncheked' else two schmitt's in series (like beer they come in 6 packs).

Good luck.

8938

Show"N"Tell ( What you have made with your CNC machine.) / Re: Home-Brew router in process - can't wait to cut!!

« on: August 10, 2008, 05:14:57 AM »

Nice machine Dave - looks like you have built it to last.
What diameter are the Y axis rails please ?.

8939

General Mach Discussion / Re: How to wire steppers???

« on: August 04, 2008, 09:29:28 AM »

Well done guys - a most educational thread.

8940

Show"N"Tell ( What you have made with your CNC machine.) / Re: Afew things I have made

« on: August 04, 2008, 08:43:38 AM »

Very nice and very professional work !

It's so good I felt that I just had to add my comments.