Messages

7121

General Mach Discussion / Re: Can you identify this controller? RC Foam Cutter (RC Foamcutter)

« on: March 03, 2017, 02:57:14 PM »

Hi,
probably didn't put that well. Most CNCers would say that they don't come better than Geko, no doubt there are some superb
and expensive brands out there but in the Mach world Geko is the by-word for quality.

The G540 is a combined device, it has 4 built in stepper drivers and IO amps to match one PP. I've seen it advertised for just under
$300 US which is good value for it quality and therefore VERY popular amongst CNCers. The G540 has an upper voltage limit of 50V,
which is good for most purposes but Gekos other models G203, G213 etc have 80V capable drivers. The higher voltage allows you to
drive your steppers faster at reasonable torque. Stepper motors are very poor at high speed and any and every effort is usually expended
to improve them at speed and still remain cheap. The G203s etc are a single driver, ie you require one for each axis and also a BOB
and therefore costs more than a single G540 so you pay quite a premium for the extra speed.

If you are 'made of bucks' and/or really need your machine to whizz around to make money then you need genuine servos. Some of the
cheapest crappiest servos are the same price as a good stepper and drive but any midway-to-good servo and amp is way more expensive
than a stepper and drive.

Craig

7122

General Mach Discussion / Re: Pulse frequency way off

« on: March 03, 2017, 02:35:28 PM »

Hi,
kool! The PP can be very sensitive to seemingly unrelated settings but usually pretty good once everything settles down. You can see
also that ANY other programs running while your machining can spell disaster. Programs which require automatic updates which
include Windows are a pain.

Craig

7123

General Mach Discussion / Re: Pulse frequency way off

« on: March 03, 2017, 04:06:21 AM »

Hi,
yeah really crappy, its seems to look worse the more often I see it...

If you open the Task Manager and have it open along side the Driver Test window you may get lucky and spot a process/thread which
is running and clashing with Mach. This does not always work, some threads use very little in the way of resources but throw all sorts
of interrupts which bugger Mach up.

Craig

7124

General Mach Discussion / Re: Can this computer run mach3

« on: March 03, 2017, 01:51:39 AM »

Hi Malcolm,
computers are especially good at making people look like plonkers, and just to think its only going to get worse. Good luck.

Craig

7125

General Mach Discussion / Re: Pulse frequency way off

« on: March 03, 2017, 01:45:48 AM »

Hi,
sorry just had a look at your Ytube post, that looks really crappy....

Some process/thread/application on your PC is causing it. A lot of threads on a PC communicate with each other using the
interrupt system and despite anything we can do Windows tends to decide on interrupt priority often at the expense of Mach3s
Pulse engine.

There used to be a list of things that you could do to your PC to improve things, I haven't seen it for a while but it helped me when
getting started. You might look in the section 'Mach3 on Vista'. Any of the suggestions there are likely to help.

If you get really frustrated the buy yourself a UC100, PMDX411 or a SmoothStepper and never look back...

Craig

7126

General Mach Discussion / Re: Pulse frequency way off

« on: March 03, 2017, 01:36:06 AM »

Hi,
I assume you're using a PP? Can you post a screen shot of the Driver Test screen.

Sometimes the fastest 'you beaut' PC runs a PP like a dog and an old XP clunker goes really well.
Its a good idea to try the Driver Test at increased frequencies, not that you intend on using them on your machine but higher
frequencies stress your PC and OS and will show up timing issues. Note that if you change frequency you have to restart Mach
to get to stick and you can only do higher frequencies with a licenced copy.

Craig

7127

General Mach Discussion / Re: Can you identify this controller? RC Foam Cutter (RC Foamcutter)

« on: March 03, 2017, 01:28:17 AM »

Hi,
sorry I can't identify them either, I see they have Toshiba TB6600 driver chips. That pretty much means made in China.
In fact at first I thought I saw a wisp of smoke leaking out of one... but no just granulation of the pic.

If you are using this machine for commercial use do yourself a favour and replace it with a Geko 540 or better if you can afford
it. Then you don't have to worry about or fiddle with the controller just get on with some real smart Gcode to cut some great designs.

Craig

7128

General Mach Discussion / Re: Cnc router motor upgrade opinions

« on: March 03, 2017, 01:14:56 AM »

Hi,
I think I go with garyhlucas on this one. 425Oz/in works out to 2.2 ft lb or 3 Nm, with 5mm pitch 20mm dia screws to
give a stall thrust of 4000N or 400kg force, isn't that enuf?

The trick of course is to maintain that at speed which with steppers is all but impossible.

I use small Vexta 5 phase steppers of about 90Oz in thru 10:1 low backlash planetary gearboxes. The output torque, at low speed,
is 880Oz in or about 6Nm, tons of grunt but fairly slow. I run them at 2400 rpm with the gearbox output shaft at 240 rpm for rapids
of 1200mm/min with 5mm pitch screws. Its only a small machine so I don't usually fall asleep when doing rapids.

What impresses me is that 5 phase steppers are considerably smoother running than two phase steppers and the loss of torque at speed
is less pronounced.

I have recently bought another stepper for an A axis, a Vexta 5phase 34 size, 804Oz in direct. It supposed to run at 2.8A but I have it running
on a 1.4A drive at 3000rpm no sweat!

I'm using Vexta drivers and they produce about 150V peak, so its probably no wonder that they speed along OK....
If you want speed consider 5 phase steppers, they're rare and expensive likewise good high voltage drivers. Probably little to pick and
choose between them and genuine servos but they are QUICK.

Craig

7129

Mach4 General Discussion / RS485 Modbus vs Step Direction

« on: February 26, 2017, 12:38:04 AM »

Hi All,
have at work been introduced to Dynatorch software which controls 'distributed control' axes using RS485. Axes achieve
co-ordination when 'started' simultaneously pre-established position/time tables. Very clever.

The plasma table has X and Y axes executing simultaneously, ie co-ordinated movement in XY yet Z can be executed independently
offering regular Z axis movement and THC differential movement.

All motion controllers I've come across for Mach4 are step/direction types which offer co-ordinated movement in XYZ but then can't offer
differential Z movement for THC within one co-ordinated move, or at least without intervention from the motion control card, which few if any
offer at this time.

Is there any specific reason that a motion plugin could not be written for Mach4 which copies this behaviour?

Craig

7130

Mach4 General Discussion / Re: Getting started with Mach 4

« on: February 17, 2017, 05:01:59 PM »

Hi,
1)make sure the PMDX plugin is loaded into the plugins folder of Mach4Hobby.
2)create a personalised profile in Mach4 probably copying one of the standard profiles
3)open Mach4 with your personalised profile and configure PMDX plugin in Machs Plugins as enabled, restart
4)open Mach4 and configure PMDX as your active motion controller
5)open PMDX plugin config dialogue and assign motors, axes and pins per PMDX/G540 instructions
6)the only input you require initially is a Estop. Read and re-read G540 and PMDX manuals until you have got
the Estop right, nothing useful will happen until and unless this is correct.

Craig