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Z axis now freaking out
« on: November 01, 2007, 09:40:45 PM »
Hi there!

About a week an a half ago I STOLE a nice CNC bridgeport on ebay and WAS this close to cutting my first part (REALLY) until...

I turned the computer off and now have a "axis 4" (on main screen only) not set up or in any setups.

My abnormal light was blinking (1 or more axis enabled/disabled I believe) until I told it not to error (mistake). Nnow it says axis not refed to normal conditions (I WAS trying to setup a homing system on x & y but never really got it and it appears to still be setup without homes.

PROBLEM IS: when I jog.. x& y work as expected... but z uses reversed keys and goes WAY faster than it's supposed to & setup to be! I had this working perfectly for days :(

Besides my problem I'd also like to know:

What is an "a" axis?

What is "Event driven serial control" and "servo serial feedback" (which asks for a password) checkboxes in setup do?

Reason I'm so concerned is my servos (Aerotech BM800's) have the normal 2 millitary cables, but also a 9 pin pigtail.  It all came wired and ziptied and the 3 9 pins went to the computer where the 2 extra com ports are not even active in windows!?!?  Aerotech tech says the 9 pins shouldn't be used???

I'm using a sound logic parallel board. SPECIAL THANKS TO ROBERT for help getting my timing issues resolved & motors tuned!!!

World servo sst-1500 servo drivers



Re: Z axis now freaking out
« Reply #1 on: November 02, 2007, 07:45:33 AM »
Is this a MACH controller system? what version?

(;-) TP
Re: Z axis now freaking out
« Reply #2 on: November 02, 2007, 10:17:56 AM »
sorry, yes it's version 2.56 registered


Re: Z axis now freaking out
« Reply #3 on: November 02, 2007, 10:45:48 AM »
You might want to go back into config and check some settings. You can reverse the direction of the Z axis  in the pins and ports settings.

Next go back to motor tunning and recheck your step settings and speed/accel  settings for the Z axis.

WHat problems are you having setting up the homing. Do you have the limit switches working? Does it have separate home switches?

An A axis is normally a rotary axis mounted in the x axis plane or y axis plane. But it can be anything as a 4th axis.

(;-) TP
Re: Z axis now freaking out
« Reply #4 on: November 02, 2007, 11:03:41 AM »
Thng is I've gone over everything I can think of and it looks normal.
The axis reverse is not reversed in pins & settings. 
My step speed acel is cranked way down to almost nothing and it's still moving much faster than it should (although not as fast as it could).

I only have x&y limit switches..I was trying to make those home switches and didn't realized they were 2 different animals.
Re: Z axis now freaking out
« Reply #5 on: November 02, 2007, 12:55:07 PM »
I've just re-instaled over 2.56 with 2.58. My motor settings were retained but my z axis is still whacky.


Re: Z axis now freaking out
« Reply #6 on: November 02, 2007, 02:10:52 PM »
First things first, did this machine come ready to run or have you rebuilt it yourself??

OK now the homing. Yes you can use the limit switch as a home switch just set it to the same pins and ports as the limit switch you want to use( Mach will know the difference) Then set up homing to tell MACH which direction to home to.

The A axis.  Go to pins and ports and look at the A settings  if it is checked as active then uncheck it.

Now the spindle. Did it always do this ?? So if you press the pagedown key on the keyboard the Z goes up?? How about from the Jog panel ( press the TAB key) click on the Z- button does it still go up???

When you jog up or down what does the Fspeed dro on the main page read as you are moving

Next what are your settings for steps per unit in the Z axis motor setup?? 

What are your settings for Velocity and accellaration.

In the pins and ports setting for z do you have the  "DIR active low" checked or unchecked????

Move the Z into the middle of its travel and press the ZERO button next to the Zdro that reset the axis to zero. Next from the MDI line type in     G1 Z-1 f3    and press enter.

THe z  should go down 1" at 3 IPM(veryslow)  does it go up or down???? slow or fast??

(;-) TP
« Last Edit: November 02, 2007, 02:23:47 PM by vmax549 »
Re: Z axis now freaking out
« Reply #7 on: November 02, 2007, 07:39:09 PM »
Well, it was 99.9% ready to run. I rebuild nothing. The machine was said to have cut 2 parts and based on the chips on the grease I believe it. 1st off someone scarfed the digital video card. then the dual com board wasn't seated correctly or installed in windows.  the 3 nine pin connectors from each servo apear (and according to aerotech) to do nothing.  There was a mach 2 demo installed.  It looks to be a very professional retro using quality components.

I now have "axis 4" on the program run screen but ony x,y,z setup in port&pins. I do not remember it being there earlier.

The knee (not spindle). no it WAS working perfectly.  yes, PgDn moves it UP. NO - the Z- jog moves it DOWN, but way too fast.

When all was working at 45kHz it was around 20,000.  I'm runnning 25khz (since upgrade today & haven't officially retuned) now and even with ridiculously LOW #, it still moves way to fast. I'm talking like 100 steps, vel & acell all the way down to 1 !!!

under motor outputs dir active low is OFF for ALL axises. Step low active is CHECKED for all as well.

After I enter the code, a few seconds later the table moved DOWN FAST.

Thing is...when my z moves this fast, it makes a horible screeching sound that we can't identify where it's coming from. The locks are off, the ways aren't getting gouged, everything is well lubed including the screw. I do not let it make this noise very long...which is why I didn't answer your question about the feed DRO yet.  IT says .45 when I set steps to 2000, 4.9v 31 acel. it says about 10 in x&y

There is a couple second delay when moving the z axis not present in the other 2.

As a bald guy, I'm REALLY frustrated!  I did BTW install 2 small programs before this happened. Autoeditnc and cncsimulator. Both free utilities that should" have nothing to do with this. Other than that the PC is quite pure down to Arts exact instructions of a clean xp which got my "pump" relay from clicking on & off a million times a minute.


Re: Z axis now freaking out
« Reply #8 on: November 02, 2007, 09:25:34 PM »
OK the scretching noise concerns me, it sounds like a runaway servo. Possible a bad encoder or broken encoder wire. How do you stop it when it starts to run fast??

The axis 4 I am assuming is the dro display, you would have x y z 4 correct? NOrmal the program is setup to run 4 axis if needed.

The abnormal flashing would be normal if you did not ref home. If you double click on it you can then reset it as normal. yes it will tell you that the axis have not been ref. Normal for that situation.

The nine pin cable , if the manf told you not to worry then don't.(;-)

This is a knee driven Zaxis. If you push pagedown button the knee should move upwards. If you push pageup it should move downwards.

If when you type in the code at the MDI and it waited several seconds and took off you may have a runaway servo, bad encoder or broken wire or bad connection could cause it. Or you may have a bad servo drive. The only way to check is to check all the components wiring and verify the encoder works.  Or switch axis leads with another axis and test each component.

Be very carefull , a runawy servo can be deadly in the wrong conditions.

(;-) TP
« Last Edit: November 02, 2007, 11:01:10 PM by vmax549 »
Re: Z axis now freaking out
« Reply #9 on: November 03, 2007, 02:01:53 AM »
the screeching noise has us concerned too.  It only happens on z and only happens when moving much faster than I anticipate ever cutting aluminum.  It's a really harsh ringing type sound. can't picture it being anything but the iron of the machine. happens more on the down stroke. I don't like to make the noise and we were unsucessful trying to follow it with a mechanics stethascope. Quite possibly I changed the keystroke to be more intuitive. I have NO cnc experience and had the keys and a joystick (now disabled) working how one would think.. ie up is table up...I see your point now.

thanks for the advice and the warning.  I hit esc to e stop when it screeches.  will try playing with it tomorrow...and I'm sure Sunday as well. Have a great weekend and thanks again.  Rob