MechMate CNC Router Forum

Go Back   MechMate CNC Router Forum > After Building the Beast - Operating , Troubleshooting and Maintenance > Troubleshooting
Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Reply
 
Thread Tools
  #1  
Old Fri 23 October 2009, 07:16
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
Motors loosing steps - Breakout board not suitable

Let me first introduce my build. My MM is part something else and the x rails throught the z-slide is true MM. I first started my CNC experience building a table for a plasma cutter but quickly figured out I would get more use from a router.

So the table is built from 1.5" x 1/8" wall square tubing. Two hundred feet to be exact. Then I built the gantry from MDF and used some THK linear rails that were about to be junked at work. To make a long story shorter I stumbled onto the MM site after I had been frustrated that my new creation was not accurate enough.

So began the rebuild. I opted to keep the original table and just add the mm components. I got the parts from Joe in alabama and the v rollers from SuperiorBearing.

I originally ordered 4 203Vs from Gecko and they recommended Keling to purchase my motors and PS. So I ordered a KL-7220 power supply, 2 KL34H2120-42-8A, and 2 KL34H295-43-8A. I got the belt reducer idea from Chopper and made a couple of adjustments so I have 4:1 reduction on all of the axis driving a 40 tooth pinion.

After getting all of the wiring done and mach3 setup I tried my new toy. Doing a simple 0.5" jog at 10 ipm all axis are +/- 0.002". I thought that was pretty good. Time for a test cut. I made a sample cut out of a 4" square. I cut it at 20 ipm and everything came out perfect. It made 4 passes at 1/4" deep. Perfect.

Then came the real test. I have a flag the I had created on VectorArt3d website. Created the g-code in artcam and exported using the mach3 post processor. I tried cutting it at 100 ipm and it came oute terrible. Every time it started a new slice the Y axis didn't return to the true starting point. It was actually too far positive. So it was making offset stairs. When it was over the y axis zero was actually about 1.25 inches greater. I have the motors wired ( 2120 = Bipolar parallel ) and ( 295 = Bipolar series ).

So i guess I am asking is 72 volts too much? Should the motors be wired different even though they are precise at a low speed? I attached several screenshots from how i have mach setup. Thanks in advance for any help.




Reply With Quote
  #2  
Old Fri 23 October 2009, 10:15
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
According to my calculations, the 2120 can be run up to the Gecko's maximum of 80VDC and the 295, when wired series, can be run at 80VDC.

In your setup, you have Motion Mode set to Constant Velocity instead of Exact Stop.

Your acceleration (ramping) seems a little fast to me. I like to use 0.5 second to 1.0 second, depending on the material that I'm cutting. Fast acceleration could lead to missed steps.
Reply With Quote
  #3  
Old Fri 23 October 2009, 11:50
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
Thanks,
I will try that next.
Reply With Quote
  #4  
Old Fri 23 October 2009, 15:43
mikefoged
Just call me: Mike #27
 
Randers
Denmark
Send a message via MSN to mikefoged
I run mine with Constant Velocity, the exact stop it will do anyway becourse of the Stop CV on angles is set to 90 degres in yours set up.

Ill will try to set that to about 75 degres and changes your lJ Mode from absolute to inc.
Reply With Quote
  #5  
Old Sat 24 October 2009, 21:28
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
Changed my acceleration down to 1. I am still getting the stair step look when I cut out a simple square. I attached some photos of what I am getting. When looking at the pic X+ is up and y+ is to the left.




Reply With Quote
  #6  
Old Sun 25 October 2009, 00:44
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
From this thread, Typical settings for Mach motor tuning, your original motor tuning with acceleration = 25 inches/sec/sec was okay.
Reply With Quote
  #7  
Old Sun 25 October 2009, 03:57
javeria
Just call me: Irfan #33
 
Bangalore
India
Mark chk your parallel port cable resistance (should be less than 1 ohm)., chk if the steps per unit you have set is absolute.say if you give command to move it 100 units it should move 100, if not that will also cause problems like this.
Reply With Quote
  #8  
Old Sun 25 October 2009, 07:34
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
How are you holding the material to the table? Is it moving?
Reply With Quote
  #9  
Old Sun 25 October 2009, 07:44
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
How should I check the port resistance? I am screwing the material down, so it isn't moving. When I do a step jog at 1" it will go +/- 0.002". Is that to much? I thought it was pretty good for wood. I am checking that with a magbase and indicator.
Reply With Quote
  #10  
Old Sun 25 October 2009, 09:36
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
Sorry I didn't read the whole post about checking my cable. Will try that this morning. I have tried the same cut at differnet speeds ( 10 ipm - 200ipm ) and different steps per just trying to make something change. Also with and without backlash. I checked my step per again this morning with 1" jogs at 20 ipm and they are not the same everytime. For the first four they were spot on at 1" then the next one was 0.005 short the next was 0.008 short then they were good again. Any clue as to why this would happen. That could be the whole problem. Just can't figure out how to fix it.
Reply With Quote
  #11  
Old Sun 25 October 2009, 09:47
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
javeria,

You might be onto something. I checked the cable resistance and pin to pin varies from 1.8 to 2.0 ohms. I am going to cut it and redo the ends to see how much that will lower it.
Reply With Quote
  #12  
Old Sun 25 October 2009, 16:50
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
Fixed it. After changing all of the settings and making a new cable with < 1 ohm resistance I was still getting the steps. So I thought to try and drive the 203vs with just the parallel port. TaDa. no problems at all now. The nice CNC4PC C11 Multifunction board was the problem. now I just need to find out if they will replace it. I hope so I'm not keen on throwing money away. Thanks for the suggestions.
Reply With Quote
  #13  
Old Sun 25 October 2009, 19:33
smreish
Just call me: Sean - #5, 28, 58 and others
 
Orlando, Florida
United States of America
Mark,
You are not the first person to have challenges with the CNC4PC product board. The PMDX is under 100 bucks.....well worth the jump if they wont replace it.
Sean
Reply With Quote
  #14  
Old Sun 25 October 2009, 21:53
Richards
Just call me: Mike
 
South Jordan, UT
United States of America
Congratulations!

That is the kind of problem that can take years off a man's life before it is solved.

The Gecko G203v requires Active HIGH step signals. Common is tied to ground. Many boards give Active LOW signals. The PMDX-122 breakout board can be jumpered to give either Active HIGH or Active LOW. I've used it with the G202 stepper drivers, that require Active LOW signals and then rejumpered it for use with the G203v stepper drivers that require Active HIGH signals. When properly jumpered, it worked perfectly with either the G202 or the G203v stepper drivers.
Reply With Quote
  #15  
Old Mon 26 October 2009, 02:13
javeria
Just call me: Irfan #33
 
Bangalore
India
Quote:
Originally Posted by smreish View Post
Mark,
You are not the first person to have challenges with the CNC4PC product board. The PMDX is under 100 bucks.....well worth the jump if they wont replace it.
Sean
ditto - also I dont like IC's on their holders - lets a whole bag of problems out!
Reply With Quote
  #16  
Old Mon 02 November 2009, 06:52
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
Thanks to Arturo from CNC4PC for quickly shipping me my replacement board. After I did a couple of checks he requested and sent him a thermal image of the board to show there were no hot spots he replaced it for me. Now my MM is up and running great.
Reply With Quote
  #17  
Old Mon 02 November 2009, 07:10
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
Did Arturo say that the board needed re-design, or was it faulty and needed repair? (that could change the title of this thread)
Reply With Quote
  #18  
Old Mon 02 November 2009, 11:01
mgandy02
Just call me: Mark
 
Minden, LA
United States of America
I have not heard back from him. I will keep you posted when I get an outcome. My board was version 3.1 and the replacement was 9.3.
Reply With Quote
Reply

Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
All motors run fine then start chattering and loosing steps - interrupt in the PC KevinL Troubleshooting 24 Wed 14 October 2009 22:11
Milwaukee Router weirdness - SSR (solid state relay) not suitable jeffh Troubleshooting 26 Thu 26 March 2009 13:03
Loosing steps - noise interference problems MariusL Troubleshooting 14 Sun 15 March 2009 06:34
Power supply for the PMDX-122 Parallel breakout board - 9V AC from main transformer bradyaero 702. Power Supplies 14 Mon 01 December 2008 16:00
Alternative to Mach3 and Breakout Board using USB dmoore Miscellaneous / General / Whatever / Catchall 0 Thu 22 May 2008 13:59


All times are GMT -6. The time now is 00:32.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.