Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: RiffRaff on December 13, 2011, 10:58:08 AM
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Hi Newbie here
I bought the Zentools 7x7 cnc and have Mach 3
I'm having trouble setting up the home switches
I have 2 switches in series for each axis so they are both home and limit switches
when I hit ref all z axis homes perfect but the next one y will hit the switch and keep going
I've read for hours on this site and elsewhere but can't figure it out
any help would really be great
Tim
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Sounds like you may have the switch set up wrong in Mach, if you attach your xml file I can see if there is a problem with your config.
Hood
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Thanks for your help
Guess I'm a total newb, it took me awhile just to figure out where the .xml file was
I just got as far as getting the motors to move at that is it
Tim
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sent you a private message
Hood
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If you go to the Diagnostics page in Mach and then press a switch on the X axis, do the M1 Limit/Home LEDs light or do the M2 ones light?
Hood
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Ok Sorry about that
reinstalled latest version with proper lic
hopefully I'm good to go
new xml
pressing on z switch light up all 3 m1 lights
pressing on x (right and left) switch light up all 3 m3 lights
pressing on y (back/forward) switch light up all 3 m2 lights
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X should be M1
Y M2
Z M3
so if yours are as you say you need to swap the pin assignments round in Mach.
Hood
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Awesome thanks
rewired it and it homes correctly now
When I hit a limit switch how do I reset so I can move it off the switch?
I'm having to turn them by hand to get them off the switch
Thanks Hood
Tim
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getting excited
Now to find a good first program to try
Anyone?
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When I hit a limit switch how do I reset so I can move it off the switch?
I'm having to turn them by hand to get them off the switch
Settings screen ... Limit Override
Now to find a good first program to try
Anyone?
http://www.machsupport.com/forum/index.php/topic,18345.0.html
... and there's the Roadrunner in the default Mach3 GCode folder.
Russ
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I already tried the roadrunner gcode without a bit or anything just to see if it worked
It did run the code but the whole thing was maybe an inch square and the most
so I'm guessing there is some kind of scaling issue I have to deal with or is that how big the roadrunner actually is?
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I looked at your xml and native units are set to mm so I presume thats what you want?
If you have the steps per unit set correct for motor tuning then all will be fine. The reason the roadrunner is tiny is the code is in inch but there is no G20 at the start telling Mach to use Imperial units, so if you put a M20 on the first lne of code it will run proper size. Remember though you will need to set back to metric with a G21, you could put that on the line before the M30 in the code and it will set to metric automatically as you end the file.
Hood
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Thanks Hood
I have no idea how to go about this but I will do my best to find out how
I looked at the code and see nothing of what you mentioned
Is there a resource for all the different codes and how to use them?
Thanks
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Ok I added g20 to the begining of the file and now it seems to be way to big
Maybe it was meant for a bigger table?
Mine is only 7 inches by 7 inches (Zentool 7x7)
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According to the extents on the Toolpath page the roadrunner is 7.7" x 6.3" see screenshot.
If you click on the G Code button on the main page of Mach you will get a list and description of G Codes.
Are you meant to be set up in mm as default units or will you work in imperial units normally?
Hood
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The only reason I have it in mm is because thats the way the video was set up
I tried changing to inches and it was still to big
sorry for all the trouble
guess I have lots of reading to do
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Ok set the native units to inch if thats what you will normally use then you will have to set your steps per unit accordingly. If you tell me how many microsteps your drive has, if you have gearing between motors and screws and also the pitch of the screws I will let you know the steps per unit.
Hood
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Haha, ok, I'll have to get back to you on that as I have no clue
All I know is I have the zentool 7x7 kit http://www.zentoolworks.com/product_info.php?cPath=14&products_id=74
and all the accessories that came with it
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Ok I have Nema 17 motors
M8 x 1.25 Stainless Steel Lead Screws with ball bearing end support
and this is my motor driver http://www.zentoolworks.com/product_info.php?cPath=16&products_id=111
no gears between motor and screws
hope thats the info your looking for
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Will need to know what microstepping you have the drive set to, it can do full, half, 1/8th, 1/16.
Also just to confirm, you are wanting to use imperial?
Hood
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Ok imperial is just fine if it is easier
Mirco steps are set to 1/8
again thats only because its the way it was shown in the instructions
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Found this on the zentool site
I will try this tonight
Please use 32512 steps/unit for all three axis if you are using inch unit. The driver is set to 1/8 micro step by default(you can change it). So 25.4(mm/inch) / 1.25 (leadscrew pitch) * 200 (full steps per revolution) * 8 (microstep) = 32512 steps/unit.
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ya still not working correctly
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That should be the correct steps per unit if you have kept the drives at 1/8 stepping, did you also remember to fist change your native units to Inch from the Config menu then Set Native Units?
What is the actual problem now?
If you go to the MDI screen and zero the X DRO then command a G0X1 from the MDI line does it travel 1 inch?
Hood
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Sorry Hood, It works perfect now, it was my learning how to zero the work on the table that needed work
got it now
My digital calipers show exactly 1 inch which I think is amazing
any tips on motor tuning?
Tim
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Steppers are in a way the easiest to set up as you dont have to do any real tuning between the motor and drive like you have to do with a servo. They are however a bit more problematic setting in Mach as you do not have any idea what the max velocity will be where with a servo you do.
Its been a long time since I used steppers but the way I used to do things was have the accel at a low value and keep increasing the velocity and testing until the motor started stalling. I then dropped that by 50% and then increased the accel in steps until the motor again started stalling. From there I knew the max of each individual component and could workout a happy medium but again it was trial and error even to find the sweet spot.
One thing I will say however is to my mind it is much better to have a fast acceleration with a slower Velocity than the other way about, that is why I love servos as you can have both but steppers you have to trade one against the other.
Hood