Messages

61

General Mach Discussion / Re: Strange backlash compensation

« on: June 24, 2007, 08:02:15 AM »

Graham,
In the case of continuous jog mode you are correct that Mach3 does not know but the first
move will be at least more than the backlash comp so in my case it would automatically add 0.1mm
to that first move in the new direction without including that extra distance in the DRO calculations.

Another way would be to mathematically subtract the backlash distance from the DRO and then
just jog as normal.  The first 30 steps or so in my case would not move the table but they would
be counted by the DRO so 30 steps later, the DRO would be back to the starting value and the
backlash would be taken up.

Please remember that I am new to Mach3 and the Micromill so I am probably doing something
wrong in the configuration or otherwise but the backlash is clearly not working correctly on my
system and on tmsmith’s .  Also the backlash distance is very small so it ought to be completely
transparent; tmsmith was using 5/1000 and I am using 8/1000 (0.1mm).

The part that I do not understand is why there is a separate backlash speed.  If a G code directs
a movement in the opposite direction so backlash is required, I believe that the backlash move
should (or could) just be part of a normal move that is mathematically handled in the background
and then the normal acceleration and speed setting would handle that combined move.

By the way, I am extremely happy to have found Mach3 and the related products and the support
through from Art and Brian and the user community is fantastic.  I specially like the feature that I
can customize Mach3 to fit my needs and taste.  I have spent yesterday playing with LazyCAM
Pro but I save that for another post.
Have a nice Sunday!
Bertho

62

General Mach Discussion / Re: Strange backlash compensation

« on: June 23, 2007, 09:15:33 PM »

The problem is there regardless of my backlash speed setting.  It is very obvious and disturbing. 
I push continues jog and the axis accelerates up to speed and then it slows down to a crawl
where it presumably adds the backlash and then it accelerates up to speed again.

Sort of:  Oops! I forgot the backlash, let’s stop, and do the backlash comp before proceeding.
I fail to understand, which would not be the first time, why there should be a speed or other issue. 
If the next move is 10mm back, why not just add the 0.1mm backlash comp and make it a 10.1mm move.
Bertho

63

General Mach Discussion / Re: Strange backlash compensation

« on: June 23, 2007, 04:59:37 PM »

I am at least happy to hear that I am not the only one with this problem.
The backlash compensation really should be completely transparent. 
If a move is in the same direction as the previously move, do not do anything.
If the direction changes, add the backlash distance to the next requested
distance and then do a single move to that location.

I do not understand why there is a special “backlash speed” option.
Bertho

64

General Mach Discussion / Strange backlash compensation

« on: June 23, 2007, 10:42:03 AM »

I am running the latest official Mach3 on a fast Win-XP and a DSLD 3000 Micromill..
With the backlash option disabled and running a program or jogging it behaves as normal. 

In metric mode I set backlash to 0.1 and I tried federates from 1 to 100% with the same problem behavior. 
It is most obvious if I jog in fast (continuous) mode.

The table accelerates as normally for maybe 20 mm and then slows down to a crawl (presumably doing the
backlash comp) then it accelerates up to normal speed again and continuous fine.  Another jog in the same
direction works normally.  If I jog back, it does the slowdown to take care of the backlash and then subsequent
 jogs in that direction works fine.  If I disable the backlash option all is back to normal.

Should it not be doing the few backlash comp steps first and then go full speed to the next point. 
The same thing happens when a program is running.
What am I overlooking or what should I do differently?
TIA,
Bertho

65

General Mach Discussion / Re: Mach-3 interface questosn

« on: June 14, 2007, 12:09:18 AM »

I tried setting the debounce as suggested but there was no change, still the blinking abnormal light
Bertho

66

General Mach Discussion / Re: Mach-3 interface questosn

« on: June 13, 2007, 09:39:15 AM »

Hi Chip,
I think you mixed up my question with the other users magnetic switch questions. 
I have temporarily placed regular micro switches as home sensors and I have
470 ohm pull-ups to +5Vand they appear to work just fine. 

I am in the process of adding high accuracy switches but wanted to quickly get
it up running and to understand the system.  The switches that I am working on can be seen at:
http://www.vinland.com/Opto-Interrupter.html

Thanks again,
Bertho

67

General Mach Discussion / Re: Mach-3 interface questosn

« on: June 12, 2007, 10:58:33 PM »

Thanks for hanging in with this problem.
It works and indicates all Normal until I bring any axis to home. Clicking for example Ref "Z" on the
diagnostic screen makes the Z slowly go home, hit the home senor and slightly back up and then
automatically set the Z axis to 0.  As soon as it goes to 0, the abnormal light starts blinking.
Bertho

68

General Mach Discussion / Re: Mach-3 interface questosn

« on: June 12, 2007, 07:36:33 PM »

Thanks Chip,
Hood suggested that too but I am stubborn and since I am new to Mach-3, I am really trying to
understand the guts of it.  My old engineering background motto is: “Do not fix it until
the problem is understood”.  Letting the computer do it, I will never know what was
wrong or what is waiting to pop up and bite me.

I love this program, especially with the Screen-4 so I can tweak it to fit my needs. 
After getting used to it I will see how I can tear out the existing controller for my
Universal Laser System CO2 laser and control it much better than the existing Windows driver.

At least Hodd has duplicated my failure using my configuration file so it is presumably
something I miss-configured since it is the first time setting it up.

Bertho

69

General Mach Discussion / Re: Mach-3 interface questosn

« on: June 11, 2007, 07:09:08 PM »

Hood,
I really appreciate that you are taking the time to help me.
Attached is the file in question.
Bertho

70

General Mach Discussion / Re: HELP pleeeeeese Z axis problem !!!!

« on: June 11, 2007, 06:47:06 PM »

If it works fine for 1/2 hour and then gives you trouble, and the problem is worse when hot weather,
it sounds like something is overheating.  A bigger motor would not help if it is the driver overheating. 
How is the ventilation in the driver box? At least temporarily hook up a fan blowing on the drivers and see if it helps.
Bertho