Decimal point in the wrong place

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billthefarmer
Posts: 16
Joined: Sun Nov 08, 2020 3:44 am
Acorn CNC Controller: Yes
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Decimal point in the wrong place

Post by billthefarmer »

Hi there,

I have most of my CNC machine now working, the distance traveled is correct but the decimal point needs to shift two places to the left. I realize this is probably something simple but I have no idea how to change it. I took a clip from one of your other videos showing the readout with the decimal placed correctly. I also have attached a snip from my screen which should be reading.. X 401.4 mm Y 964.6 mm and Z 16.3 mm.

Another question on many of your videos, you show a fast job rate of 200 in./min my screen asks for mm/min can you just do a conversion of X 25.4 which which is 508 8 mm/m I am now using 50 MM and the travel is 1165 mm in 15 seconds so somewhere it looks like this is also decimal in wrong places.
Your help would be much appreciated.

Regards Bill
Attachments
report_0035FF8E3E4A-1014203830_2020-12-22_13-14-26.zip
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metric wrong display.PNG
METRIC DRO.JPG
martyscncgarage
Posts: 9912
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Re: Decimal point in the wrong place

Post by martyscncgarage »

Sorry,
I am metrically challenged.....
If you home the machine first, then set your part position using F1 Setup
Which will Zero out your DRO's and set your G54, then you go into MDI and command say a 50mm move, does it move 50mm and show 50.00 on the DRO?
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
swissi
Posts: 573
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Re: Decimal point in the wrong place

Post by swissi »

billthefarmer wrote: Tue Dec 22, 2020 12:09 am Hi there,

I have most of my CNC machine now working, the distance traveled is correct but the decimal point needs to shift two places to the left. I realize this is probably something simple but I have no idea how to change it. I took a clip from one of your other videos showing the readout with the decimal placed correctly. I also have attached a snip from my screen which should be reading.. X 401.4 mm Y 964.6 mm and Z 16.3 mm.
Just take a Sharpie and draw the decimal on the screen where it should be. Just kidding! DON'T DO IT!!!!

Looking at your Report file, you Motor mm/rev values (0.2496mm) seem to be way off and probably the reason for your decimal issue. This value should be the distance your axis moves when the motor axis makes a full 360 degree turn. Lead screws usually have a pitch between 2 - 5mm and if you are using a gearbox and don't direct drive the screw with your motor you have to divide those 2 - 5mm by the gear ratio.
billthefarmer wrote: Tue Dec 22, 2020 12:09 am Another question on many of your videos, you show a fast job rate of 200 in./min my screen asks for mm/min can you just do a conversion of X 25.4 which which is 508 8 mm/m I am now using 50 MM and the travel is 1165 mm in 15 seconds so somewhere it looks like this is also decimal in wrong places.
Imperial/Metric conversion is really not that difficult: 1" = 25.4mm, that simple. 200inch/min = 25.4 x 200 = 5080mm/min

If you set your control to Metric, all parameters must be entered in Metric.

-swissi
If you are using Fusion 360, check out my CNC12 specific Post Processor
If you are using a Touch Probe, Tool Touch Off Device or a Triple Corner Finder Plate, check out my ProbeApp

Contact me at swissi2000@gmail.com
billthefarmer
Posts: 16
Joined: Sun Nov 08, 2020 3:44 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 3830
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No

Re: Decimal point in the wrong place

Post by billthefarmer »

Thank you for your advice or change the ratio of the turns to decimal places it is now 24.96 that fixed the decimal in the wrong place. Marty also suggested that I enter a G code for a straight line and let him know what distance the machine moved. I still have to figure out how to write the G code for decimal equivalent to inches. Nearly all the videos I watch are in inches. In one of Marty's tuning videos he he gives example this G code...
g1x1f10 am I correct if I convert that this way...g25x1f250 is that the way to convert it to metric.
By the way I am using 20 mm ball screws directly driven by NMEA 34 closed-loop stepper motors Leadshine HBS86 drivers I set the dip switches to 3200 it's very hard to find any actual information how to set this up everyone shows the basics but not the nitty-gritty. As I said I'm very new to this if you can make any other suggestions I would appreciate it. Thanks a lot Bill
martyscncgarage
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Location: Mesa, AZ

Re: Decimal point in the wrong place

Post by martyscncgarage »

G1X25F25

G1 is a linear move requiring a federate command.
X is the X axis
25 is the distance traveled
F25 is the federate of 25mm a minute

Download a copy of the mill operators manual from the Centroid website and read up. Lots of good information in there.
https://www.centroidcnc.com/centroid_di ... nuals.html

Also go to YouTube and search for Centroid Mill Training and watch the two videos.
Cnccookbook.com is a good resource
Good luck.
Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
swissi
Posts: 573
Joined: Wed Aug 29, 2018 11:15 am
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Re: Decimal point in the wrong place

Post by swissi »

billthefarmer wrote: Wed Dec 23, 2020 3:24 am Thank you for your advice or change the ratio of the turns to decimal places it is now 24.96 that fixed the decimal in the wrong place.
By the way I am using 20 mm ball screws directly driven by NMEA 34 closed-loop stepper motors Leadshine HBS86 drivers I set the dip switches to 3200 it's very hard to find any actual information how to set this up everyone shows the basics but not the nitty-gritty.
First you need to get the Steps/Revolution value right. This MUST be exactly what your driver is set to. So when you say the dip switches are set to 3200, this value MUST be 3200

P1.png
P1.png (7.31 KiB) Viewed 3558 times

You can test if this is correct by setting Steps/Revolution to 3200 and Overall Turns Ratio to 1mm/Turn.
Draw a marker on the motor coupler of the X (Axis 1) axis , go into the MDI and enter the command G91 X1 F10. If your Steps/Revolution are correct, the coupler should turn exactly one revolution and the marker should be at the same place again as before the move.

If that's correct, you need to find the exact pitch of your ball screw. The 20mm you mentioned is most likely the diameter of the screw and not the pitch. The pitch is most likely 5mm. Take a ruler (or a dial indicator if you have one), turn the screw exactly 1 turn (you can use the same command in the MDI as above to do that) and measure how far the table traveled. What ever you measure (4 or 5mm most likely), that value needs to go into the Overall Turns Ratio field.

When you have this two values correctly, you can test again if the values shown in the DRO match the distance the table travels. Go into the MDI again, command a G91 X10 F100 and measure if the table travels exactly 10mm (X=Axis 1, 10=10mm, F100 is the feed rate of 100mm/min).

billthefarmer wrote: Wed Dec 23, 2020 3:24 am I still have to figure out how to write the G code for decimal equivalent to inches. Nearly all the videos I watch are in inches. In one of Marty's tuning videos he he gives example this G code...
The Metric/Imperial conversion is not that difficult. When you install CNC12 you choose if you want your machine to be part of the modern world then, you select Metric or if you want to remain in the stone ages, then you select Imperial (I'm just teasing! Don't send me hate mails but you can guess what I prefer :D ). But what ever you choose it's not that big of a deal. The only difference is that your DRO will show values in Inch or mm and the values given to a command are interpreted by the control by default in the units the control is configured with.

What's important to know is that there is a simple command to tell the control that the values that are being used in your commands are in mm or Inches. That command is G20 for Inches and G21 for mm. So no matter what the default units of your control are set to, when you command a G20 G91 X1, the machine will travel 1 inch and with a G21 G91 X1 the machine will travel 1mm. No need for you to recalculate values in inches or mm. Just tell CNC12 that your commands are in inch (G20) or in mm (G21).

As Marty suggested, read the CNC12 Mill Operators Manual and you will learn a lot about all these G and M commands.

Hope that helps.

-swissi
If you are using Fusion 360, check out my CNC12 specific Post Processor
If you are using a Touch Probe, Tool Touch Off Device or a Triple Corner Finder Plate, check out my ProbeApp

Contact me at swissi2000@gmail.com
billthefarmer
Posts: 16
Joined: Sun Nov 08, 2020 3:44 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
CNC Control System Serial Number: 3830
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No

Re: Decimal point in the wrong place

Post by billthefarmer »

Thanks a lot for your help Marty and Swissi, you put me on the right track. I had to change the dip switches to 4000 and then put the same in the steps/revolutions and then the ratio of 4.992 which I calculated on Marty's spreadsheet. Now everything works perfectly it taught me a lot about the relationship with some of the data that I enter while I was trying other figures on the driver and the software I actually got to the stage where the homing switches were not clearing because they were not moving back enough. Originally I was told from the suppliers that the drivers are set correctly and when you try and get help good luck. That was using the cheap MACH3 China USB also impossible to get good information. And I came across the Centroid Acorn I definitely cost more but are very very well with the extra specially for the professionalism and the help supplied.
Thanks again have a Merry Christmas and happy new year to all involved. Regards Bill
martyscncgarage
Posts: 9912
Joined: Tue Mar 28, 2017 12:01 pm
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Location: Mesa, AZ

Re: Decimal point in the wrong place

Post by martyscncgarage »

Hi Bill,
Glad you are making progress!
That's what we are here for, to try and help each other with suggestions to try and get back on track.
Merry Christmas and Happy New Year to you and yours as well.
Marty
Reminder, for support please follow this post: viewtopic.php?f=20&t=383
We can't "SEE" what you see...
Mesa, AZ
Arthur
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Re: Decimal point in the wrong place

Post by Arthur »

Hello all,

I just wanted to drop in and thank you guys for this post, which helped me to solve scaling issue on my router. I was off by x10 on DRO of my machine and now moving to solve the mirror image on Y axis :) I am suspecting that it has something to do with WCS and X,Y, Z orientation choices in Fusion 360.
Any input on the matter is welcomed!

Thanks again.

Follow up:

Quickly figured out that I had to inverse Y axis :)
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