Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: SINBAD on December 09, 2008, 07:35:10 PM

Title: Motor problem
Post by: SINBAD on December 09, 2008, 07:35:10 PM
Hi, I've just joined the forum, having just built a CNC Router. After having problems getting an output from the parallel port, which I eventually  found was a problem with the port driver, I now have an output, but the motors will only oscillate. They move in one direction for a fraction of a revolution, then reverse for the same amount continually when in jog mode. All my electrical equipment is Keling.

 

 
Title: Re: Motor problem
Post by: Hood on December 09, 2008, 08:00:04 PM
Try setting the pulse width on motor tuning page to 5. Also make sure you have the motors coils connected the right way.
Hood
Title: Re: Motor problem
Post by: SINBAD on December 09, 2008, 11:22:12 PM
You're a genius Hood. Why is it the thing that you don't check that is the problem? One of the steppers was not wired correctly when I joined the pairs, and the wiring to the drivers from the other motors was also incorrect. Only myself to blame! I now have motors turning when I toggle, but they go in one direction only, whether I hit plus or minus. Maybe I've wired something else incorrectly. Thanks again Hood.
Title: Re: Motor problem
Post by: Hood on December 10, 2008, 02:34:49 AM
Make sure your Dir pin is asigned properly, might also need the active state of it changed.
Hood
Title: Re: Motor problem
Post by: SINBAD on December 10, 2008, 05:36:11 PM
Hi Hood, I've checked the port assignment, and swapped the pin assignment for step and direction, and it has no effect. I changed the active state and same result. I checked all wiring from the motors to the drivers, and from the BOB to the drivers, and all appears correct. When the motors run in one direction, the correct one I assume, they run smoothly, while in the opposite direction they are rough and jerky!

Many Thanks, Denis.   
Title: Re: Motor problem
Post by: Hood on December 10, 2008, 05:41:55 PM
 To Test that the Dir signal is coming out of the PP you can disconnect the cable and put a voltmeter between the ports Gnd pin and the Dir pin and jog one way then the other, you should see 5V one way and 0V the other. If that works then put the cable back and check at the other end of the cable, if its getting there then put the cable back on the BOB and check the output Dir pins from the BOB.
Hood
Title: Re: Motor problem
Post by: SINBAD on December 10, 2008, 06:58:16 PM
I checked the the voltage coming out of the PP and it is 3.5V. When I jog it drops to 3V. When I jog the other way the voltage does not change. The voltage at the BOB pins is 5V, and when I jog I get the same result with the voltage dropping to 4.2V when jogging one way, and not changing at all the other way. The motor runs roughly when the voltage drops, smoothly when it remains high. The BOB is powered at 5V by it's own transformer.
Denis
Title: Re: Motor problem
Post by: Hood on December 10, 2008, 07:02:24 PM
Can you attach your xml, you will find it in the Mach3 folder. If you are using the standard Mill profile it will be called Mach3Mill.xml, if you are using a custom profile it will be the name of your custom profile.xml. You will need to copy the xml to your desktop and then rename it before the forum will accept it as an attachment, suggest you call it Sinbad.xml

Hood
Title: Re: Motor problem
Post by: SINBAD on December 10, 2008, 07:22:33 PM
I have the xml file Hood, but cannot work out how to send an attachment with this reply. There doesn't seem to be a button in "quick reply", the only way I know to give you an answer, which allows you to add an attachment, as in normal email programs.
Denis.
Title: Re: Motor problem
Post by: SINBAD on December 10, 2008, 07:25:11 PM
I think I have it worked out. Here is the xml.
Denis
Title: Re: Motor problem
Post by: Hood on December 10, 2008, 07:43:24 PM
OK the likely problem is you have a load of OutPuts enabled and they are using the same pins as the Motors, disable them on the outputs page unless you need them and if you do then you will need to asign them to different output pins from the motors.
Hood
Title: Re: Motor problem
Post by: SINBAD on December 10, 2008, 08:21:42 PM
You were spot on Hood, I had a friend "helping" me a few days ago, and he fiddled with a lot of the settings trying to get the motors to work. He knows less than I do about MACH 3, and I know precious little. I told him I didn't think what he was doing would make any difference. I thought I had reversed all that he had done, but obviously missed his fiddling on the outputs page. The motors were still not working when I fixed the outputs page, so I tried checking the active lows in the DIR and STEP boxes, and when I set the STEP to low active they functioned correctly. It certainly is a steep learning curve when you start in CNC, but thanks to you I'm continuing my slow crawl up the slope.
Many, many thanks, Denis.
 
Title: Re: Motor problem
Post by: Hood on December 11, 2008, 01:58:11 AM
Denis, we have all been there and to be honest we are all still learning. Mach is so versatile that you discover new things every day. Great you have it working now and any more problems just shout and I am sure if I cant help there will be many here who can.
Hood
Title: Re: Motor problem
Post by: Barneydog on December 12, 2008, 07:38:23 AM
Use the motor tuning to turn down the velocity of the motors. May be trying to force them too fast. Turn down to 50 then try. If it works gradually increase.
I had the same prob. Some instructions on the net say start highest but then you exceed the motors max speed. Start low and slow.


Julian
Title: Re: Motor problem
Post by: SINBAD on December 12, 2008, 08:03:03 AM
Thanks Julian. Now that I have the motors going I will be doing a lot of experimenting to find the best speed etc.

Denis.
Title: Re: Motor problem
Post by: BluePinnacle on December 12, 2008, 12:31:58 PM
acceleration values matter too, if the motor can't spool up quick enough it may trip over itself. the motor tuning dialog is useful for determining what's what.