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Author Topic: Jogging =DRO  (Read 3093 times)

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Jogging =DRO
« on: September 05, 2012, 07:17:12 AM »
Hi I was watching the hoss video regarding backlash so basically set up mach3 the same jog step 0.0100 velocity 58% but when I jog I was expecting the DROs to increase in steps of 0.0100 but they increased 0.0102 0.0204 0.0306 0.0399 0.0501 restart 0.0000 0.0102 0.0204 0.0297 0.0399 0.0511 this happens on both X and Y each time I try, Some of the numbers will be different but not all. The motors are switched off.
Probably the reason I'm spending so much time making scrap instead of parts  8) ???

Offline Hood

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Re: Jogging =DRO
« Reply #1 on: September 05, 2012, 07:36:36 AM »
You steps per unit will be such that your minimum resolution will be 0.0102.
Hood
Re: Jogging =DRO
« Reply #2 on: September 05, 2012, 07:57:05 AM »
Ok so I changed the step to 0.0102 now I get 0.0102 0.0204 0.0206 each increasing by 0.0102 bit more reading and playing I thinks.

Offline Hood

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Re: Jogging =DRO
« Reply #3 on: September 05, 2012, 08:00:59 AM »
Mach can only put out a full pulse a minimum distance so whatever your steps per unit work out to is what you will have. The only way to make the resolution better is increase the steps er unit. Obviously the steps per unit are governed by the type of motors, microstepping of drives, ballscrew pitch, gearing etc so you cant just change the steps per unit, you would have to alter some of the aforementioned factors.

Hood
Re: Jogging =DRO
« Reply #4 on: September 05, 2012, 02:49:06 PM »
The motors are 200spr I'm using a xylotex board set at 1/4 steps and using the existing sx2 screws which have a pitch of ?1.5mm when I test I get 1.5mm of travel when I rotate the Handel 1 turn. Now according to the info I have read I should enter 200 x 4 / 1.5 = 533 into the motor movement profile but if I use the steps per unit in settings over a distance of 152.5 mm it gives a setting of 1066.9328. Helps appreciated I'm missing something fed up of reading . Had a thought 200 x 8 / 1.5 = 1066.6667 checked the jumpers on the xylotex and thers a jumper across ms1 which should be 1/4 not 1/8 if I changed to 1/2 steps on the xylotex would that be a bad thing ?

Offline Hood

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Re: Jogging =DRO
« Reply #5 on: September 05, 2012, 03:26:33 PM »
Changing to 1/2 stepping would reduce your resolution further.
Your calcs are correct so assuming the motors are 1.8 degree steppers then it sounds like you either have gearing between motor and screw or the drive is not set right for the microstepping. What happens if you set the dips to 1/8?

I am not sure I follow when you say "but if I use the steps per unit in settings over a distance of 152.5 mm it gives a setting of 1066.9328."
You set the 533 in motor tuning. If you then zero the DRO and command a move from MDI of say 100mm it should move 100mm, ie zero the X DRO and in MDI type G0X100 then press enter on your keyboard, the axis should rapid 100mm.
Hood
Re: Jogging =DRO
« Reply #6 on: September 05, 2012, 04:47:31 PM »
If I do this http://www.youtube.com/watch?v=XkO5tc-jSxw&feature=youtube_gdata_player I get a reading of 1066.9328 so I opend the  xylotex checked and it's 1/8 so my caclc of 200 x8 /1.5 is ok . If I go into MID and enter G0 X 152.5 the Quill moves 152.5 and the dro = 152.5 all ok . Now if I set jog to 0.010  and jog the Quill the Quill moves 0.010 but the dro 0.0102 0.0204 0.0306 what I was trying was this http://www.youtube.com/watch?v=buXHZ_McbOY&feature=youtube_gdata_player probably a gremlin

Offline Hood

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Re: Jogging =DRO
« Reply #7 on: September 06, 2012, 03:06:07 AM »
First thing is the Quill should be Z unless you are referring to the tool moving and not the actual axis of the quill?
Please attach your xml and I will have a look.
Hood
Re: Jogging =DRO
« Reply #8 on: September 06, 2012, 04:34:03 AM »
Morning  i was referring to the tool. attached is the xml file.

Thanks
Re: Jogging =DRO
« Reply #9 on: September 06, 2012, 05:22:02 AM »
don't use the themill.xml file its the wrong one also i i Am using the blue screen version so my xml file won't work withthe original mach screen may be that's the problem .