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Bob:

Is it set to "autoZero the DRO"? This should stop the softlimits from
applying when the ref is done. It shouldn't be possible to hit a limit with
softlimits enabled as the softlimits should be set to maintain just in front
of the switch...hmm. Does doing a ref, help?

Art
www.artofcnc.ca

I have a new CNC router that I build set up to run.

I am trying to figure how to back off a limit switch using software limits.

If I go to the correction page and toggle the software limits, I can then go
back and move off the limit, but the system will now not recognize my
limits.

In the correction page I can not get the red software limits light to go
off.

Bob Campbell

It seems than when there is a direction change inside a single command (e.g.
G02), there is no effect to the exact stop setting.
For axample:
G1 x0 y0
G2 x0 y0 i10 j0
In this case there is a stall posebility in 4 points.

I used G61 and G64 and the effect is the same.
When the direction changes the other axis stop moving for a brief period of
time (enough to stall it).

Thanks, Isak.

Steve:

I will lookinto user settable index points. I was thinking of some sort of
memorized points at any rate. In the end, whatever's needed will be
provided. :-)

Art
www.artofcnc.ca

On Sat, 23 Aug 2003 10:02:09 -0600, you wrote:

Yes, but the majority of CNC lathe operations are centerline and inside
tools. Typically I have turrets loaded with a 4:1 ratio of inside tools to
turning or grooving tools. Most operations don't even require x-axis
motion. Most lathe parts have many more center drilling, drilling, boring,
tapping, and conventional turning and facing operations than back face
turning and grooving.

That may be the type of stuff you do, but we dont all have turret
machines, or do that sort of work. If I was doing that I'd be DNC'ing
via a high level commercial program - not using Mach2!

In the trade, Z safe is considered the "safe" place to make a turret index.
Ideally, just far enough away from the work that the longest tool won't
collide with the work piece during an index. There is no X safe. That's the
programmers responsibility...

Mute point any way - we are not getting any now - thanks!

--
Steve Blackmore

Isak:

This should only happen in CV mode, or if your acceleration is too high.
Lower your axis acceleration to a ridiculous level to see if it does indeed
decelerate and accelerate. Then make sure the backlash is set to a proper
speed for the correctrion because backlash is not ramped.

Thanks,
Art
www.artofcnc.ca

Bob:

As yet, radius compensation is not active, nor is constant surface speed.
Feed per rotation is implemented. Turn still has a very long way to go
before anyone could call it complete, but it is coming along. Due to the
huge user base at this point I am proceeding very carefully to maintain the
reliability we've managed to extablish. I don't want to screw up people with
paying jobs so I hope to keep progressing as painlessly as I can for all.

Thanks,
Art
www.artofcnc.ca

Rich:

Nope, the CAM programs will work it out for you. Most safeties in this
regard are used when a user is writing their own code or MDI'ing their way
through stuff. I will try to take all thius into consideration when I get to
wizards.
Thanks,
Art
www.artofcnc.ca

At 08:42 AM 8/23/03 +0100, you wrote:

On Fri, 22 Aug 2003 18:52:10 -0600, you wrote:

The safe move on a turning machine is the Z axis, same as a milling
machine. You move the carriage away from the chuck axially(+Z). If you
moved the X axis with a drill buried in the work piece, you'd have a nasty
situation. IOW...Safe_Z would be the same move for lathes or mills.

That can be be sorted with Z inhibit (not the same as Safe_Z)

The problem with turned parts is they often have grooves, or diameters
smaller at the chuck end, (nearer to Z0) - this is not a common
occurance with a mill. What happens is with some combinations of tool
offsets tool will try and rapid back through work, due to compound XZ
moves.

Yes, but the majority of CNC lathe operations are centerline and inside tools. Typically I have turrets loaded with a 4:1 ratio of inside tools to turning or grooving tools. Most operations don't even require x-axis motion. Most lathe parts have many more center drilling, drilling, boring, tapping, and conventional turning and facing operations than back face turning and grooving.

In the trade, Z safe is considered the "safe" place to make a turret index. Ideally, just far enough away from the work that the longest tool won't collide with the work piece during an index. There is no X safe. That's the programmers responsibility...

-Bob

Art,

I explained what the trade considers "Z safe" in a response to Steve. It's just a safe place to index the turret during program execution. The actual position is established in the program in a number of different ways depending on what features the control has.

I'm excited about Mach2turn. I'm currently using AHHA on one turning center that I'd like to upgrade. I don't have an XP or W2000 machine, so I can't evaluate it yet. Will Mach2 install on NT4? I see you have threading working now. Do you have constant surface speed and tool radius offsets going yet?

-Bob

--- In mach1mach2cnc@..., Art <fenerty@a...> wrote:

Good point. In lathe, you never really
know which axis needs to move first

Am I being dumb or overtrusting, in expecting MasterCAM/whatever to
work all this out for you?


Richard

On Sat, 23 Aug 2003 09:05:38 -0400, you wrote:

There's a limit as to what you can do in software for safety?

Not when the world is full of litigious Americans ;)

If my OD tool is in a groove (or behind a shoulder,) i must do X+
before I go to TC. If the tool is inside a bore, i must go Z+ first,
to clear the hole, before I rapid to TC.

I am aware of that, I'd already assumed you would withdraw the tool
from the stock - the problem can arise with Mach2's compound moves.
Once it's done the withdraw, say from a groove, it will do a compound
XZ move to the next G0 position - it may well take your tool tip
through the stock.

The other ways round it is to code separate X & Z moves on their own
lines, or make a series of compound moves to safe positions.

No need if a Safe X is in operation, tool will always withdraw outside
the stock max diameter before moving (if set right;)

Boring is a very different situation, an X- move is needed to clear
the tool tip from the cut (not enough to hit the other side of the
bore) then a Z+ to clear the tool from the bore - All that should be
catered for in your Gcode. You can't cater for everything.

For indexing, you need a safe X and Z both.
But to optimize a job, and index close to the work,
it must be possible to index anywhere. It's the user's
responsibility to be sure there's enough room.
For tool work and hobby, safe index is a good idea,
but don't make it mandatory.

Nobody suggested it be mandatory, just as it is in mill - a user
setting box or boxes- if you care to ignore it - fine.

--
Steve Blackmore

On Fri, 22 Aug 2003 23:22:46 -0300, you wrote:

Found it. When a file loaded, it was running the macro thread in the
backround without waiting for the previous one to finish. If a second was
started while the first was running, an error would occur. Since the first
macro call of a system takes a bit longer than others in order to initialize
the scripting engine, it would cause this "race" condition to occur.

Great stuff - looking forward to a repaired version.

Next headache threads ;)

--
Steve Blackmore

Hello Mika,

No question, go with the higher sampling rate. I started with a
20Mhz and now I have a 100Mhz looking after a 200Mhz. The reason why
is because the osciloscope is a tool to "see" what is happening as
you know, but what if you don?t "see" the noise, for example in
the
step & dir lines. My personal oppinion is not to start with less
than 60Mhz. About the triggering features the more the best you will
find yourself playing with them to find the disturbing peak in the
line.

Luis.

Art,

There's a limit as to what you can do in software for safety?

If my OD tool is in a groove (or behind a shoulder,) i must do X+
before I go to TC. If the tool is inside a bore, i must go Z+ first,
to clear the hole, before I rapid to TC.

For indexing, you need a safe X and Z both.
But to optimize a job, and index close to the work,
it must be possible to index anywhere. It's the user's
responsibility to be sure there's enough room.
For tool work and hobby, safe index is a good idea,
but don't make it mandatory.

dg

If the start and end aren't equal, it's not a circle/arc.

There are cases that it is impossible that those radiuses would be exactly
equal.

What cases would those be?

dg

If you can afford it get the HPS-40. The main limitation on any scope is the
sample rate. Eventually you will want to debug a problem that requires a
higher sample rate.

The other reason is that although the frequency you are looking at can be
handled by the 10MHz scope, you may say, have a glitch or noise whose
duration is shorter than the sample rate of the 10MHz scope.

Cheers,


Peter Homann
mailto:Peter.Homann@...
Adacel Technologies Limited,
250 Bay St, BRIGHTON, 3186, AUSTRALIA
<>
Telephone +61 (3) 8530 7777, Facsimile +61 (3) 9596 2960
Mobile 0421-601 665

On Fri, 22 Aug 2003 18:52:10 -0600, you wrote:

The safe move on a turning machine is the Z axis, same as a milling
machine. You move the carriage away from the chuck axially(+Z). If you
moved the X axis with a drill buried in the work piece, you'd have a nasty
situation. IOW...Safe_Z would be the same move for lathes or mills.

That can be be sorted with Z inhibit (not the same as Safe_Z)

The problem with turned parts is they often have grooves, or diameters
smaller at the chuck end, (nearer to Z0) - this is not a common
occurance with a mill. What happens is with some combinations of tool
offsets tool will try and rapid back through work, due to compound XZ
moves.

Tools on a mill retract in Z to rapid, on a lathe they retract in X
(could be a minus X too with a rear toolpost).

--
Steve Blackmore

Hi,

I need some help from experts.
I have possibility to have handheld oscilloscope from Velleman.
There is two models:
HPS10 and HPS40
The difference betveen these two is maximum sample rate ( 10MHz versus 40MHz ).
And also HPS40 have adjustable trigger level ( in 8 steps ).

My need is check encoder pulses ( TTL and Differential 5V ) and DC voltage riple.

Any advise which one I should get?
HPS40 is more expensive but is HPS10 enough for use I descripe above?

Regards Mika

Isak, could you elaborate? Is it occuring in constant velocity or is exact stop the problem? Just curious, have never tried exact stop.

Frank Carpenter