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John:

Very impressive. No wonder you've been so quiet these last couple weeks. I
have more playing to do, but this will really help get 800x600 and other
screens ready for the release. Excellent Job..

Art
www.artofcnc.ca

Tim:

In theory, they are not mutually incompatible. But in practice, it depends
highly on the hardware used. Picture a two axis interpolated circle, when
the X axis hits its 90 boundry, it must correct before the Y axis can
continue. This means the X axis must move a particular distance prior to the
Y axis taking the next step. Now if you have only a pulse or two of
backlash, you copuld probably apply it quickly, and the Y axis would not
notice the pause. But if the correction is too large, or the time of
correction too long due to slow corrections, then the Y can lose steps
because it has not slowed down enough to allow for the pause in pulseing on
its axis while the X does its correction.

I have seen system that show no effect from backlash, and I have also seen
the reverse. CV is affected in this because of its assumption that its OK
for Y to be going at speed when the X reverses fopr backlash correction. I
think even in EMC, if you up the pulse count of the backlash, you'll find
you lose steps. This is something that differs from user to user, so I
always advise that they are incompatible, though they are not always.

Art
www.artofcnc.ca

Hi John:

Great job as usual!!!!!

Tried out the scaling and seems to work great.

Thanks for hard work.

Bob Harvey

Hi John:

YOu must trun on backlash on the state config. Unless its on you'll have no
change. The backlash is adjusted in the background and the correction takes
place when an axis reverses movment. This means constant Velocity should not
be used. Play with it a bit and see how well it works for you.

Good luck,
Art
www.artofcnc.ca

If any of you are interested, Tiger Direct has trackball mouse for
$2.99. This one is nice if you don't have much room at the machine.

EdpNo=493049&Sku=B20-9114&CatId=143
Richard

Hi All:

Before I start this I should say that my "Manual" is not the latest update--printer is too tired to print that out often.

My MDF Router has Backlash (surprise). 006" on "X", 009" on "Y" and 006" on "Z"

Not too bad for cutting Balsa, but can I do better? I tried entering these figures in the "Configure Backlash" page, but my measurements, via MDI haven't changed. I still have the same Backlash. I'm satisfied that I'm measuring it correctly and it's consistent.

My Manual gives very little info on "Backlash" compensation. I have absolutely no idea what "Backlash Speed % of Max" means nor what it does.

Should I just leave "Well enough Alone" or play some more?

Thanks again

John Bell

--- In mach1mach2cnc@..., "Erie Patsellis"
<signworks@c...> wrote:

any problems with my math????

Go to and get a
copy of motioneering with which you can simulate your whole system.

As for rack and pinion, if you divide the pitch diameter of the
pinion by 2 then you have the effective radius. From there it's just
Torque = Force * Radius


Richard

just built it and gantry weighs 135# takes from 10 oz to just
over 16 oz. force to move it I have a choice of 180 oz
steppers or 600 oz servos both drives would be reduced 3.5-1
and one revolution = 2.25 inches

Is the stepper(180x3.5=630oz.) strong enough and fast enough

and is the servo to problematic for plasma??




I still use windows 98 so cant see demo version of mach2-is it a good
choice for plasma is there visual torch simulation can i change speed
can i pause can i make corections if somthing gos wrong can i
controle torch hight what all do you get in the torch mode and
is it clutered with unused confusing boxes etc. for other tooling
when in plasma mode signed bewilderd new guy

Hi to all who have worked with ScreenDesigner

ScreenDesigner is a wonderful tool for customising our systems but you may have had frustratuions when a new release means you have to do lots of cut-n-paste to get your features onto the new screens from Art.

He has also proposed a rationalisation to handle mill workflow better so screens may be volatile for a bit yet!

Rev A2 of the Mach2Mill manual will document the format of a .SET (i.e. screen Layout) file. I have written a utility to test my understanding of this format and in the hope it will be useful. It allows the following:

(a) Delete screen(s)
(b) Move screen number within a layout so number in Designer is position when using Mach2
(c) Append screen(s) from another layout (to include one;s own favorites)
(d) Re-caption screen selection buttons to the logical F-keys etc.
(e) Export data on the controls from a layout to a text file for analysis and documentation purposes
(f) Resize screen or layout to smaller or bigger screen resolution
(g) Order DROs so arrow key moves through them more logically (not rev A1-1)

The program and its documentation, a Windows ActiveX implementation which you may not have if you do not use other Visual Basic applications, and a sample Layout to import screens from are in a Zip in the folder M2ScreenTweak on this group.

The source also is available if you want to "play" with other features (not-for-profit). You will need Visual Basic 6.0 Professional or Enterprise edition. Let me know off list if you want access to the source files.

Comments and suggestions welcomed as always

John Prentice

OK, given the following:
Application: Rack & Pinion Gantry router, work area is 8' x 13'

Motor Specs:

37.51 oz-in/A (Kt)
25.0 - 30.5 V/kRPM (Kv)
Terminal resistance 0.75 - 1.02 Ohms @ 4A
Max terminal voltage 60V
Max continuous speed 2100RPM
Max peak torque 1500 oz-in
Max peak current 44.5A (unsure)
Max continuous stall torque at maximum motor temp 300oz-in
Max continuous current 8.9A

Reduction Calulations:

a 40:1 drive reduction with 24 d.p. rack, 30t 24 d.p. pinion (effective
circumfrence of 3.926 inches)

desired rapid of 400-500 ipm (approx 100-125 rpm pinion speed)

I calculate I would need a 2.38:1 ratio from motor to reduction unit, does
this ((125*40)/2100=2.380)
will give me a torque at 20 amps(gecko 340 max current) of
(37.51*20)/2.38*40=12,608 in oz)or 788 in lbs of force.

anybody remember how to calculate force at the tool with a rack & pinion

drive?

1024 count quadrature encoders * 4= 4096 counts per rev, 2100 rpm=35 rps,
35*4096=143,360 pulse frequency, in excess of
mach 2's limit of 45 Khz, I'll have to use a pulse multiplier of either
x5(28672 khz) or x10(14336 khz).

If I go with x5, I end up with about 3500 steps per inch, x 10 is around
1750 steps per inch.

any problems with my math???? suggestions as to which way to go (x5, x10)



Erie Patsellis
Shelbyville Design & signworks
217-774-4444
signworks@... <mailto:signworks@...>

Visit our website at:

Art,

On your spindle speed control, when selecting PWM as the out put,
what is the timing of the Min Width and the Max Width of the pulse? I
am testing a PWM Intergrator circuit and need to set the Local Osc
Rate so that the Full Width give me a full Binary count and the min
Width gives me a zero count.

Mark Esser

"Alan Trest"
wrote:

Ok Guys,

We are drifting here.
Try and keep it on track please.

Alan

John Prentice wrote:

and snipping the earlier citations would have removed 70 lines from
this message ;=)

Absolutely good point John:
Thanks,

Alan

Joe,

Please drop me a note offline and I will give you some information and
prices on VisualMill.

Bob Campbell
KE5JO
Euless, Texas
bob@...

This feature is used on the Bridgeport EZ Trak
and on the Southwest Prototrak. Both machines were
designed with prototype/short run jobs in mind.
There are other controls which also do this, I think.

It is common to want to put a chamfer (or radius)
onto a part on an ad hoc basis. By punching in the
angle or radius, and then using the handwheel, the taper
or radius is cut "manually". You can move the tool forward
and backward, and it stays glued to the angle or radius.

What's needed to go with this are handwheels.
I don't want to switch my lathe over till I can
use handwheels. I still do manual type work with it,
and having to jog instead of a dial is not realistic.
Any predictions, Art?


dg

Steve:

You can add the Jog mode selector to any screen and it will begin to jog.
You can also program a hot-key on your pendent to change screens for you if
you have enough buttons.

I haven't dealt with this issue well, because its like the moderation
issue. Both camps feel very strongly about their position, so the current
screens are a compromise. Adding Jog to the main screen is trivial, and
removing the MDI screen is also trivial, (Just remove the MDI page button).

We'll see how it shapes up...

Thanks,
Art
www.artofcnc.ca

On Wed, 20 Aug 2003 08:41:26 -0300, you wrote:

Hi:

A two-key jog would not affect the Joystick as long as the profiler for
the stick can send double key strokes when hit. BUT, I think it could only
be added as an option. This would screw up too many people using pendents
already made. This problem about 2 keys is exactly why Tim G. has suggested
(and it is implemented this way in Mach2Turn, that there be a positioning
screen (which has jog) and an MDI screen, which has no Jog but does have an
MDI line. The theory is to use the POS screen for jogging around and then
switching to the MDI screen, this stops any accidents from occuring from
inadvertant Jog key presses.

And what a bloody nuisance it is too!! I use a pendant for jogging,
but end up using the mouse to swap screens - really annoying when the
idea was to do away with the mouse in the first place!!

If I add an MDI box to the jog screen will they both work? If not can
you sort that, I've no objection to redesigning my screens - as it
stands now it's a pain the ass!

--
Steve Blackmore

Hi:

A two-key jog would not affect the Joystick as long as the profiler for
the stick can send double key strokes when hit. BUT, I think it could only
be added as an option. This would screw up too many people using pendents
already made. This problem about 2 keys is exactly why Tim G. has suggested
(and it is implemented this way in Mach2Turn, that there be a positioning
screen (which has jog) and an MDI screen, which has no Jog but does have an
MDI line. The theory is to use the POS screen for jogging around and then
switching to the MDI screen, this stops any accidents from occuring from
inadvertant Jog key presses.

Art
www.artofcnc.ca

--- In mach1mach2cnc@..., "Alan Trest"
<cncprojects0@h...> wrote:

Ok Guys,

We are drifting here.
Try and keep it on track please.

Alan

<snip>

and snipping the earlier citations would have removed 70 lines from
this message ;=)

It's more than just space on the Group. If you get individual mails
or view on the web then its easy to skip to the next message but if
you get the Digests or view with "Expand messages" then you have to
scroll through the dross. The <snip> is no work when replying on the
Group or by e-mail - we all need to try to "get the habit".

Best wishes

John Prentice

Option2
Use Rutex R991H Pulse to analog drive. Keep my servo amps and
replace the glass scale with a rotary encoder .

Derek,
The westamp's really are solid and already tuned for your machine.
You will avoid a lot of hassles if you use option 2 and keep them.
I've heard that the R991H's work pretty well. I've had one on the
shelf for my spindle drive but haven't got around to installing it...

Roger S