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Greg:

I was wondering if you think the system will run better on the G2002 than

off the parallel port?

In short, yes. The 6 axis pulsing engine is asyncronous and separate and
runs to 4 million pulses per second.. This makes things VERY smooth. I
haven't actually seen motors move this fast before, any stepper I've used
will lock up far before the current G2002 speeds I'm getting.
Mach2 version 4.0 can drive a Gecko in CNC movement and jogging, it just
doesn't do IO, it simulates IO as a test function. I need to finish a few
things on it. It does reduce the burden of the CPU and any laptop and such
can run it I think. I suspect even Win98 can run it, but haven't tried that
yet...

Marris has agreed to sell the 2002's for $350.00 dollars each at this point,
and its quite possible that if you ask him nicely ( He's a nice guy and like
most nice guys is a sucker for being asked nicely...) he'd put a copy of the
current Mach2 firmware in it before sending one out. That would allow you to
reburn the firmware as it gets completely finished since the Mach2 firmware
is flash upgradable through the USB port. So, if you don't need ref'ing
functions, turn functions or spindle control , the G2002 seems to be quite
usable for milling right now...

If anyone gets brave and decides to get a g2002, just let me know and I
can send a xml file which turns it on and the current firmware flash you'd
need. The more that actually own one, the higher the pressure to complete
the IO section which is only a couple hours work I need to get to. On the
same vein, anyone risking their 350.00 has to remember it is all R&D, this
is one of my problems, its easy to develop with 1000 of you using printer
ports who can bitch at me daily, but with only 2 people with Mach2 g2002's,
its quite a bit more difficult. While mine works fine, unknowns exist by the
multitude until more people are trying it out. I get feeling guilty spending
too much time on it and have to make sure the mill people have top prioity
on my time , then Plasma, then turn. The g2002 sits just under those 3
priorities. (Then there's my own mill, my life, my wife, .. ;) ..etc
..course my REAL job fits in there someplace as well...)

All that having been said, the G2003 will be fully functional within two
months if I have anything to say about it, even if its only for myself, just
because its a very nice contraption and its movement impresses me so much..

Thanks,
Art
www.artofcnc.ca

Art, I assume you intend to continue active support and development of the
Mach2 parrallel port software even after the G2002 is ready?

Although the G2002 sounds like a neat device it seems to me to be an
overkill solution- what you have in Mach now runs quite well for any
reasonable size and speed mill. Why shuold Anyone spend $350 to get pulse
rates many times faster than their motors can move?

In my view the G2002 became so feature bloated it looks like Bill Gates had
a hand in it.

ron

Ron:

Yup, the printer port will be fully supported. No worries there..

Actually, the G2002 isn't too bloated. Its fairly simple. It does seem
expensive in the hobby market at the moment, but as printer ports dissappear
it will continue to look more atractive all the time. Its simply the next
step when the makers of PC's take away our access to things like printer
ports..

Art
www.artofcnc.ca

--- In mach1mach2cnc@..., "Ron Ginger" <ginger@m...>
wrote:

Art, I assume you intend to continue active support and development

of the

Mach2 parrallel port software even after the G2002 is ready?

Although the G2002 sounds like a neat device it seems to me to be an
overkill solution- what you have in Mach now runs quite well for any
reasonable size and speed mill. Why shuold Anyone spend $350 to get

pulse

rates many times faster than their motors can move?

In my view the G2002 became so feature bloated it looks like Bill

Gates had

a hand in it.

ron

Ron

Not all people are doing machines for home use. There are many motors
that will drive faster then 45KHz (If you are looking at 1000 count
encoders).

Just my thoughts
Brian

I'm not right with you. We can go to the limit of good steppers with mach2
at 45 Khz, and we can't drive efficiently a good servo system with a higher
definition / speed / acceleration ratio. I don't speak about AC or digital
servo systems, where 45 Khz is very low, specialy if you have high PPR
encoders. Industrial machines are often at 1 Mhz frequencies, or more for
high end ones.

Even with stepers systems it should give a better response, specialy for
full or half step systems, because the timing will be near perfection.

Actually the frequency is limted to 250 Khz if i remember well. It's a good
value for hobbists, more would be too difficult to manage with. (signal
integrity problems).


The gecko 2003 is an open standard, so cheaper non modular interfaces could
come in a near futur.

It's too an opening in the direction of the futur, because nothing garantee
the parallele port and the new motherboards will continue to work with
mach2. A simple design change inside the PC low level components or a new
processor design could cause problems to the actual mach2 kernel.

More it will give the possibility to integrate mach2 in an embedded system
quite easily.



Olivier.

On Wednesday 25 February 2004 23:23, Digital audio Pro wrote:

I'm not right with you. We can go to the limit of good steppers with mach2
at 45 Khz,

but you can't ...

the reasons for this are not obvious at first ... but let me see if I can try
to explain. I have not seen Art's source code so I can only guess at how his
driver works .. but I think I am probably close.

Art has a pulse generator in what is known as 'ring 0' of the windows kernel
.. this is the 'highest priority' layer of windows. Art schedules a task to
execute at 45khz .. (probably using a mutex or some similar idea to get
somehting close to 'real time' from Windows) .. anyway .. lets say the
highest frequncy of pulses is 45Khz .. the next evenly spaced frequncey down
is 22.5khz ... if you want to generate 32Khz pulses you have to do 2 pulses
at 45khz spacing, miss one, then two more .. miss one, then 3 more etc .. so
the pulse spacing is no longer even ... the choice is either BIG jumps in the
frequncies, or non-evenly spaced pulses. This is reallity.

What happens when you feed non-evenly spaced pulses into a stepper motor? ..
power loss. The motor wastes power trying to follow the small accelerations
and decellerations of the non even pulse chain ... at low frequencies its not
too bad, 1 pulse, miss 1000. 1 pulse, miss 1001, 1pulse etc, but at high
frequncies it becomes significant. For steppers this is a killer, because it
is at high frequncies that the motor lacks torque, and you cant afford to
waste any on rough pulse trains.

The G2002 solves this. DO NOT mistake the 1 mhz maximum pulse frequency for
ever wanting to actually get 1 mhz out iof it .. that is not the purpose at
all. the purpose of such high base frequencies to act as a base from which
the actual pulses are generated is that you get very, very smooth pulse
trians. this means that you get more power from your motors, can spin them
faster, this means you can use higher gearing, get more torque at low speeds
from the mill, mor torque at high speeds too ...

So .. before dismissing the 1 mhz maximum clock rate ( I think it is 1 mhz,
it may be 4 mhz) as irrelevant .. it is never intended to use this high
frequency .. it is simply to get a very smooth, regular pulse train at lower
frequncies, to get the maximum performance out of the humble stepper. When
driven right you'll be *amazed* what they can do ...

--
RapidCut CNC Technology

CNC Plasma Cutter

I guess I am thinking to much small , home shop stuff, when in fact Mach2
has a great use in the larger machines as well.

As to the parrallel port, my daughters computer fried its port and I told
her to go to Best Buy and get a PCI parrallel port card- they laughed at
her- then found one for about $80. I guess the end of the parallel port is
near.

I think the G2002 at $350 is going to be hard to take for home shop guys
when the DeskCNC controller board is $50. I know the G2002 is MUCH more
capable, and I guess for a while yet we can still get parallel ports for the
home shop world. A 3 axis G2002 for $125 or so would be a very nice device.

No need to prolong this thread- there is clearly a need for the G2002 and I
will buy one as soon as there is software for it.

Art, you havent mentioned the OCX recently- is that revision still on your
plate? Ive got a full interactive Mill program ready to run as soon as I can
get an OCX.

ron

--- In mach1mach2cnc@..., "Ron Ginger" <ginger@m...>
wrote:

As to the parrallel port, my daughters computer fried its port and

I told

her to go to Best Buy and get a PCI parrallel port card- they

laughed at

her- then found one for about $80. I guess the end of the parallel

port is

near.

Here's a parallel port with two serials...
ebay item 3462563902.. Three Months ago they were $9.95 "buy now"
but now they are $15.95 "buy now". I got one back then and it
works fine for a second port.
John

Ron:

Art, you havent mentioned the OCX recently- is that revision still on your

plate? Ive got a full interactive Mill program ready to run as soon as I can
get an OCX.


As of next version the OCX should work fine. Just tested it last night
from VB, no trouble. Will release soon..

Art
www.artofcnc.ca