Messages

5651

General Mach Discussion / Re: CNC plasma wont cut in a straight line

« on: December 18, 2017, 10:46:06 PM »

Hi,
what is the Steps per Unit value? Could it be that you have insufficent resolution to cut an interpolated line?

Craig

5652

Mach4 General Discussion / Re: Homing Issue - Z axis won't release the switch after homing

« on: December 18, 2017, 10:41:34 PM »

Hi,
Steve is right if the home switch is triggering a limit event at the same time you can write code until the cows come home,
the limit event will stop Mach dead.

I personally prefer limit switches and home switches to be separate. This post is an example  of why. You wish Mach to treat this
switch as a home switch at the moment and therefore to ignore it as a limit switch. The fault you describe is that Mach IS treating
it as a limit switch. If you had separate home and limit switches the problem wouldn't arise. Additionally it allows you to use
good quality microswitches for home switches, for which they are ideally suited, and proximity switches as limits, again an
ideal application for them. A proximity switch is a poor choice as a home switch, it is not sufficently repeatable.

Is there a particular reason that you have combined the limit and home functions?

Craig

5653

Mach4 General Discussion / Re: Homing Issue - Z axis won't release the switch after homing

« on: December 18, 2017, 09:25:47 PM »

Hi,
you could write some code to cause it to back off and add the code to the <Ref All> script.

Mach4 is very flexible and this is exactly the sort of thing which is made possible by that flexibility.

Craig

5654

Mach4 General Discussion / Re: Homing Issue - Z axis won't release the switch after homing

« on: December 18, 2017, 05:30:26 PM »

Hi,

I have no idea and i‘m searching for a way to change the distance the z axisis has to drive back after homing

the axis backs off only as far as it takes for the switch to activate again. There is no control over how far it moves.

Craig

5655

General Mach Discussion / Re: XHC Mach3 4-axis control card

« on: December 18, 2017, 12:20:29 AM »

http://www.machsupport.com/forum/index.php/topic,36023.0.html

5656

Mach4 General Discussion / Re: New people welcome !! Come in here and introduce your self!

« on: December 17, 2017, 07:37:39 PM »

Hi Charles,
with an external motion controller the PC is pretty easy, I use a dual core Atom based board with onchip graphics
without problem. Just goes to show you can run Mach on a pretty modest platform.

If I were buying again I would go a bit better just to speed up the initial load and draw when loading large (>5Mb)
Gcode files, Pentium or i3 with 4G RAM would be plenty. 32 or 64 G SSD is enough. Note that irrespective of what spec
the platform is that you customer should avoid an Internet connection, updates disabled and without Internet you
could avoid a firewall and anti virus.

Craig

5657

Mach4 Videos / Re: Mach4 and Coroutines

« on: December 17, 2017, 12:19:24 PM »

Hi Daz,
superb work, I've really struggled with coroutines, not so much the concept but the implementation, this will help BIGTIME. Thanks.

Craig

5658

General Mach Discussion / Re: Delta servo and uc 300 5 lpt motion controller.

« on: December 17, 2017, 12:13:51 PM »

Hi,
you'll need at least four of these circuits, one each for Step and Dir for both servos. You'll probably need another four eventually, one for enable and one
for fault reset for both servos.

Given that you have to signal the Step pins at 100kHz it maybe that a simple transistor like this will be inadequate. If that's the case we'll use an IC.
Try the transistor to start with. Note I used a BC547 as I have hundreds of them but any small signal NPN transistor would do.

Craig

5659

General Mach Discussion / Re: Delta servo and uc 300 5 lpt motion controller.

« on: December 17, 2017, 02:38:36 AM »

Hi,
you have to decide whether you'll try to hook it up without a transistor/mosfet and risk blowing it or use a transistor/mosfet. It'll be too late
if you decide to hook it direct and it can't handle it.

Craig

5660

Mach4 General Discussion / Re: Limit switches

« on: December 16, 2017, 07:19:12 PM »

Hi,
I wouldn't be concerned with limit switches initially. Home switches are important though. Your proposal to use two switches each for x any y axes will be fine.

You still need a z axis home switch. If you could arrange it to be near the top of travel all well and good but its not essential.

If for instance you had to mount your Z axis home switch 20mm lower than the extreme top so that it fitted or did not otherwise foul or restrict the axis
movement. Once you've homed your machine the machine coordinate of the extreme top would be 20mm, and the bottom would be -80mm if you had
100mm of travel say. Your soft limits would be 20 and -80. I know it sounds a bit weird to have your z axis machine zero inside the boundaries, 20mm
short of the top in this example, but so what? Its not really that you use machine co-ordinates, Mach does not you. When you are working at the machine
you'll be using work coordinates.

Another alternative that may well assuage your misgiving about having the machine zero at other than an extreme of axis travel is to use the Home Offset
provision of Mach. Again with the example above with the home switch 20mm short of the top you can set the <home offset> setting of -20mm.
Then the machine would home as normal stopping on your Z axis home switch (20mm short of the top) but instead of the machine coordinate being set to zero
it would be set to -20mm. If you jogged until the machine coordinate of the Z axis was zero you would be at the extreme top of travel. The advantage is that
the top of travel is 0 and logical for us humans but your switch is at 20mm below that but that turned out to be a much better place to put the switch.

Craig