Messages

5311

General Mach Discussion / Re: z zero plate problem

« on: February 10, 2018, 09:25:00 PM »

Hi,
not sure whats going on.

Incremental vs Absolute....have a look at G90 and G91

In Absolute
G0 X10   will cause the machine to drive from its current location to X=10

In Incremental
G0 X10    will cause the machine to drive its X axis another 10 units from its current location.

As I posted earlier all touch off routines have a G31 probing command. Can you open the button macro and post the code?
I really want to see what parameters have been put into the G31 command.

Craig

5312

Mach4 General Discussion / Re: Feed rate not steady

« on: February 10, 2018, 06:38:39 PM »

Hi,
yes you can run industry standard Gcode which means all your CAD/CAM programs come into scope.

Mach4Hobby is trying to be an industrial player on a hobbyists budget. A genuine Fanuc or Seimns control would cost $20,000 and annual fees.

Craig

5313

Mach4 General Discussion / Re: Glad |I asked first

« on: February 10, 2018, 04:14:11 PM »

Hi Will,
you are correct....climb milling on ANY machine with significant backlash is a disaster waiting to happen.

What you are expecting of backlash compensation software is to replicate the same techniques that every competent machinist uses to achieve accurate
work in face of backlash. My experience is that computer software falls well behind an intelligent human operator....see my previous quip about 'squishyware'.

I think the way to proceed is to get a controller that has BLC and try it. I would caution you however that it MAY not be as good as you'd hoped and if that
proves to be the case you'll have to weather the 'I told you so'.

The quote button places two editing characters on your text input screen. Between these two characters you may paste a quote
previously saved to your clipboard.

Craig

5314

Mach4 General Discussion / Re: Feed rate not steady

« on: February 10, 2018, 03:53:53 PM »

Hi,
I notice from your other thread you are planning to replace your external controller.

It is not clear to me that the feedrate variation you are seeing is in either Mach or the controller. Most certainly the motors are driven by the controller
and from your description they sound like they a varying.

I think you should replace your controller with a 'known good' one and try the same experiment again.

I use an ESS. When I command a move say:
g1 x100 f900
the feedrate DRO shows 810mm/min. Note that I just did this experiment so these are actual numbers. I don't know why Mach/ESS don't produce exactly the
commanded feedrate . I'm guessing that the internal arrangement is such that Mach can cause a number of distinct feedrates and it selects the closest one.

Craig

5315

General Mach Discussion / Re: MACH3PLASMA LIMIT SWITCHES FOR G540/PROMA

« on: February 10, 2018, 03:08:42 PM »

Hi,
those signals are inputs to Mach. Therefore you can only use the designated input pins of the parallel port, pins 10-13 and pin 15.

Craig

5316

General Mach Discussion / Re: Nmotion Controller

« on: February 10, 2018, 07:15:14 AM »

Hi Gerry,

The new fad everone is going to is the Clearpath servos. Clearpaths are great if you are replacing steppers,as they are drop in replacements. But I see people buying them for new machines. AC servos are in many cases cheaper, and can offer 3x the performance

Yes I've encountered some people who are of the opinion that they are the way to go. They attempt to replace their existing 400oz.in stepper with a Clearpath servo of
97 oz.in. The same people point out that the overload torque is much higher, say 300 oz.in without realizing that that overload can be sustained for a few seconds at best
before the drive faults out. I had another chap whom incorrectly assumed that as the speed reduced the torque from the Clearpath servo increased rather like the
stepper he was replacing. He was rather crestfallen when I explained, with the aid of the speed/torque diagram from the manufacturer that it is not the case.

Servos maintain their torque at high speeds and for their size outperform a stepper at high speed. The same stepper is likely to have a great deal more torque
at slow speed than a servo.

If you select a servo that has the same lowspeed torque as a stepper it will be much larger and way way WAY more expensive.

I will admit that it has taken a while for these realities to filter down and displace the myths. It staggering how effective those myths are as a marketing
tool though.

Craig

5317

Mach4 General Discussion / Re: XHC Mach4 USB motion board warning and info

« on: February 10, 2018, 06:50:16 AM »

Hi,
no I don't think so.

Mach no doubt has its own output format but that output will be processed by the motion controller plugin which will then communicate to the hardware controller,
As each manufacturers controller is unique, as is the plugin, there is no standard communication stream between the PC and hardware controller.

The good news is that you've got your money back. You can now buy something that works. Use the forum to confirm that your preferred device
does in fact work.

At this time there is NO Chinese manufacturer producing credible Mach4 capable boards. If they try to tell you otherwise walk away.

Craig

5318

General Mach Discussion / Re: MACH3PLASMA LIMIT SWITCHES FOR G540/PROMA

« on: February 10, 2018, 03:56:14 AM »

Hi Dave,
I've never had a chance to play with a Proma but my recollection of the documentation I read about them did not mention limits.

It is for this reason that I argue that good, reliable, repeatable home switches are more important than limit switches

I have already made the same point to OP....if he prefers limits over a home switch...that's his choice.

Craig

5319

General Mach Discussion / Re: Nmotion Controller

« on: February 10, 2018, 03:48:30 AM »

Hi Gerry,
you have to admit that the manufacturers of hybrid closed loop stepper products 'troll' their bait very very effectively

Had they been more readily available a the time I was designing my machine and accumulating components for it I may have been one of the
customers they caught.

It has taken some considerable time that I can separate the myth from the reality. I've found also that those whom are inclined to believe the hype
about closed loop steppers are very resistant to logic that says that their belief is fallacious.

Whatever may be said about them one has to admire the persuasive message of the people selling and marketing them.

Craig

5320

General Mach Discussion / Re: MACH3PLASMA LIMIT SWITCHES FOR G540/PROMA

« on: February 10, 2018, 03:35:09 AM »

Hi,
to be honest I go with Dave here, good home switches and proper softlimts beat limit switches hands down.

I got the impression that OP needed limit switches for the Proma device.

Craig