Messages

3731

General Mach Discussion / Re: Machine movement

« on: May 27, 2013, 05:37:36 AM »

Hi Robert,

You need to disregard Hood’s modesty – he is more than smart, if fact genius comes to mind. 

Tweakie.

3732

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

« on: May 27, 2013, 03:37:48 AM »

Hi Brett,

I have sent you a PM but some more information for those that follow;

Initially (and as Jeff at the Warp9 forum suggested) I investigated electrical noise / incorrect earthing etc. (USB cables seldom have a screen to carry the PC earth via the USS to the Parallel Port cable screen) - once electrical noise / earthing had been ruled out my next thoughts was one of timing where the direction pulse was not being seen soon enough. Delaying the step pulses (to give the direction line transition more time) made the situation a whole lot worse so it definitely was not that.
In my mind there was always the possibility that if tri-state logic had been used in the SS design my stepper's driver could be picking up a false logic state in relation to the direction signal transitions so I tried delaying the direction signals and it worked.
Obviously, and as mentioned earlier, more investigation is required because 150nS is hardly worth considering as a delay so it may just be the Schmitt Trigger outputs which are doing the trick. As time permits I will look at this issue in more depth and post my findings.
The circuit I am using just consists of eight TTL gates, daisy chained for each direction line.

Tweakie.

3733

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

« on: May 26, 2013, 01:13:19 PM »

In preparation for the arrival of Mach version 4 (which does not support parallel port operation) I have been experimenting with the Smooth Stepper (external motion controller) and how it performs when controlling my laser.
Greg at Warp9 has done a great job with this product and the USS software plugin already supports the use of the M10 / M11 command set so it should have been a straight forward ‘plug and play’ exercise but unfortunately this was not to be the case.
I was getting occasional ‘wrong direction’ axis movements and after making many changes to the various USS settings nothing could cure the problem.
It transpires that my rather ‘old technology’ Alegro based stepper motor’s driver was experiencing signal related issues. After a bit of experimentation I fitted additional Schmitt trigger outputs (including a 150nS delay) to the direction signal lines from the USS and hey-presto there are no longer any axis ‘wrong direction’ moves.
Ahh - the mysteries and the wonders of electronics. 
Still some more investigation to do but I am hoping to determine just why this rather crude fix has cured my problem.

Tweakie.

3734

General Mach Discussion / Re: M3 Relay output from output 1

« on: May 25, 2013, 08:15:15 AM »

Well, in that circuit your outputs do not have enough current to drive the 5 Volt electro-magnetic relays because the HV supply is through 10k resistors. Assuming the transistors Q1 & Q2 can handle the relay current then connect your electro-magnetic relays in place of the 10k resistors R5 & R6 - remembering to connect a reverse biased diode (to suppress the back EMF) across each relay coil.
The relay parts of your circuit would then look similar to the diagram per my link.

Hope this helps.

Tweakie.

3735

General Mach Discussion / Re: M3 Relay output from output 1

« on: May 25, 2013, 04:47:12 AM »

There is a limit to the current that can be sourced from an LPT port so it is perhaps best to construct a simple driver circuit (for example; http://pcbheaven.com/wikipages/Transistor_Circuits/).

(It is a rule of TTL logic that they can sink considerably more current than they can source so as an alternative you could connect your SSR between +5 Volts and the output pin - when the pin is taken low you should have enough current for it to switch - this is the way my SSR's, requiring less than 10mA, are switched).

Tweakie.

3736

General Mach Discussion / Re: Improving mill safety

« on: May 25, 2013, 04:17:29 AM »

Jog ON / OFF - standard screen, under Tool Information.

Tweakie.

3737

General Mach Discussion / Re: Need help setting up Mach 3 for my table.

« on: May 25, 2013, 01:01:06 AM »

Hi Tony,

Basically, when you open Mach3 the title bar will show "Mach3 CNC Licensed To: <your name>". If it shows something other than your name or the unique serial number which you purchased then it is a pirate license.

Hope this helps.

Tweakie.

3738

General Mach Discussion / MOVED: CALCULO DE MICROPASOS

« on: May 24, 2013, 12:15:16 PM »

This topic has been moved to the Spanish section

[iurl=http://www.machsupport.com/forum/index.php?topic=24651.0]http://www.machsupport.com/forum/index.php?topic=24651.0[/iurl]

3739

General Mach Discussion / Re: vacuum control

« on: May 24, 2013, 01:28:22 AM »

Hi Guys,

It is usual practice to fit a reverse biased diode across a relay coil in order to suppress the high voltage spike (which occurs during the magnetic field collapse) when a relay is switched off. (Just for example;  http://www.hobbyprojects.com/the_diode/diode_protection_circuits.html)

Tweakie.

3740

General Mach Discussion / Re: Mach3 on another computer

« on: May 22, 2013, 12:07:29 PM »

Thanks for the answer. But once I could use Mach 3 on a laptop. Maybe there's something about laptops hardwares.

Could be that your original laptop had a 5 Volt TTL parallel port and your new laptop has a 3.3 Volt TTL parallel port - not all stepper motor controllers will accept the 3.3 Volt standard.

Tweakie.