Hello Guest it is March 06, 2021, 11:41:47 AM

Author Topic: X axis will not change direction during cut  (Read 5281 times)

0 Members and 1 Guest are viewing this topic.

X axis will not change direction during cut
« on: February 28, 2009, 08:14:42 AM »
Hello all, I am new to the world of CNC so bare with me please, I have recently built a 3 axis machine using Probotix components, everything seems to work fairly well, and by that I mean I can jog motors and they don't make any horrible noises (anymore) my settings could probably use some adjusting, but the problem I am having is when running the test Roadrunner in Mach 3, all seems to work well until the x axis reaches the end of the first what I will call positive (+) cut instead of reversing and cutting back negative (-) direction it continues on to a positive cut even though Mach 3 shows it correct on the screen, the Y and Z axis are working correctly, any advise would be greatly appreciated.

The Probotix is as follows:

3x SideStep Bi-Polar Stepper Motor Driver
3x HT23-400-4 400ozin Stepper Motor
PBX-2 Parallel Port Breakout Board
24Volt 4.3Amp Switching Power Supply
6ft. DB25 Male-to-Male Cable
3x 4" IDC Cable 10-pin



Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: X axis will not change direction during cut
« Reply #1 on: February 28, 2009, 08:28:27 AM »
If you jog the X axis via the keyboard can you jog it in both directions? If you cant then you do not have it wired correctly or you have pins asigned incorrectly.
Hood
Re: X axis will not change direction during cut
« Reply #2 on: February 28, 2009, 04:42:54 PM »
Yes I can jog the x axis in both directions and can even type in a G' code in the MDI, like G1X2F10 and all is well, but when running a program the X axis messes up????
I don't think this would make a difference but here is the motor tuning settings, I am not after speed at this point:

X & Y axis,
Steps 32000
Vel.    8
Acc.   1
Step Pulse  1
Dir Pulse     2

Z axis,
Steps  32000
Vel.     10
Acc.     1
Step Pulse  1
Dir Pulse     2

Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: X axis will not change direction during cut
« Reply #3 on: February 28, 2009, 04:49:14 PM »
I have no idea why it would work fine from MDI and Jogging but not when running code, only thing I can think of is it is due to both axis running at the same time, see if you can command a move via MDI for X and Y such as G1X10Y10F10 and then while it is moving MDI G1X0Y0F10 and see if it reverses on both axis at the end of the first move.
 If you want also attach your xml for the profile you are using and I will have a look and see if I can find a problem there, you will find it in the Mach3 folder and will be the name of your profile, eg if you use the standard Mach3Mill profile it will be called Mach3Mill.xml. You will need to rename it for the forum to accept so copy it to your desktop and rename to Bryan.xml then attach using the additional options button on the reply page.
Hood
Re: X axis will not change direction during cut
« Reply #4 on: March 01, 2009, 07:47:26 AM »
I ran the G1X10Y10F10 four times and here are the results, 1st run- both X&Y respond like they should starting from home positionthey both reach the end of their respected runs and both reverse like normal  ;D 2nd run- Both X&Y leave home position and after about two to two and a half inches X reverses and the DRO of course is showing it moving the right direction  ??? 3rd run- Y axis leaves home postion along with X except this time X is moving negative >:( 4th run- both X&Y leave home position reach the end of the run Yaxis reverses and X axis continues in a positive direction, I am baffled, I also ran just the X axis thru the same procedure without the Y axis and came up with the same results the x axis responded in the same sporadic behavior, I am in the process of adding Home and Limit switches to my mill I don't know if that will help, I also have attached my .XML.
I think I will check for noise and run the setup tests again to see if anything has changed, I'm grasping at anything at this point.
Hood thanks for your patients and effort on this matter it is greatly appreciated.

Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: X axis will not change direction during cut
« Reply #5 on: March 01, 2009, 08:13:25 AM »
Will have a look at your xml to see if there are any issues with it but noise is the favourite so far,.
Hood

Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: X axis will not change direction during cut
« Reply #6 on: March 01, 2009, 08:31:07 AM »
You have slightly high settings for the Pulse widths on motor tuning page ;)
 Try setting these to 5.
Hood
Re: X axis will not change direction during cut
« Reply #7 on: March 01, 2009, 10:06:01 AM »
Ok I set those to 5 but still the same results......
I did notice on my driver test that I have some high spikes, possible noise, I'm not sure how to properly get rid of this unwanted noise...? could that be what is causing this behavior?

Offline Hood

*
  •  25,838 25,838
  • Carnoustie, Scotland
    • View Profile
Re: X axis will not change direction during cut
« Reply #8 on: March 01, 2009, 10:13:37 AM »
If your driver test is bad it will cause you problems but not sure if direction change would really be one, usually just very rough motors and missing steps etc.
 You may need to change the Active state for your direction and step pulses, I am not familiar with these drives so dont know which way they should be set.
 If it is noise I would say it  is more likely to be on your Dir wire from BOB to drive, do you have shielded wires for ytour Step/Dir to the motor?
Hood
Re: X axis will not change direction during cut
« Reply #9 on: March 01, 2009, 05:08:48 PM »
Yes all wiring is 22 gauge and shielded.
Are you talking about the 3x 4" IDC Cable 10-pin from the BOB to the individual drivers as possably being bad and causing the noise?
Forgive me but what do you mean by Active State?
I did find this in the driver paperwork "The SideStep is negative logic. The STEP, DIRECTION and ENABLES lines should be inverted in your software", I don't really know what that means but I thought I would mention it.