New CNC Plasma tablet Build

All things related to the Centroid Acorn Plasma system.

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ultramegaok
Posts: 6
Joined: Mon Mar 05, 2018 3:10 pm
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New CNC Plasma tablet Build

Post by ultramegaok »

Hi all

I'm in the middle of making a cnc plasma table (5X10) for the shop.. The Frame is made of 2.5 steel profile. except for the raiser of the gantry they are made of aluminum. The gantry is made of 14 Gauge metal sheet (laser cut and bend). I'm using 20 mm linear rails in both axes X and Y. for the motor I was planning to use nema23 stepper motor that I already have, but I'm open to any suggestion to change for servo motor instead. I'm using the Rack and Pinon system from Avid. Right Now I'm struggling with the settings in cnc12 software, I had followed the manual and set my stepper to 2000 micro stepping 2.36Amps of current , but When I measure the motor Revs per inch my calculation for overall turn ratio is around .942129 according with centroid documents the happy zone for this setting should be 1.5 to 2.5 anyway here's the first problem that I have.....If I move the X Axe 1 inch with G1X1F150 the gantry moves very close to 1 inch (.997) but if I move the gantry 20 inches the real movement is 21.590". I can make this several times and get the same reading which I think is not electrical wiring (I measure the actual movement with a digital read out). Why is happening that ??? what I'm missing ??

All the control parts are mounted temporary for testing purpose but once we get the right setting will be mount in an electrical panel (24X24 Panel).

Here's some photos :
https://photos.app.goo.gl/XP9n694svB7UubL3A
Attachments
report_98F07B2D4600-0422225984_2022-08-11_14-47-23.zip
(2.17 MiB) Downloaded 20 times
ShawnM
Posts: 1223
Joined: Fri May 24, 2019 8:34 am
Acorn CNC Controller: Yes
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MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 7804734C6498-0401191832
Location: Clearwater, FL

Re: New CNC Plasma tablet Build

Post by ShawnM »

What stepper drives do you have? Most all stepper drives should be wired to the DB25 and not the headers where you have them wired currently. With them wired to the headers and at the rate you are moving them at you are more than likely losing steps. The manual states that the DB25 is for stepper drives and the headers are for servo drives. Also, slow the machine down from the 800 IPM you have it set at currently. You gotta crawl before you can walk, or run in your case. :mrgreen:
ultramegaok
Posts: 6
Joined: Mon Mar 05, 2018 3:10 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: New CNC Plasma tablet Build

Post by ultramegaok »

I thought that you can choose between DB25 or the headers. I'll try the DB25...

BR
Fabian
ShawnM
Posts: 1223
Joined: Fri May 24, 2019 8:34 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
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MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 7804734C6498-0401191832
Location: Clearwater, FL

Re: New CNC Plasma tablet Build

Post by ShawnM »

Hi Fabian.
You don't get to choose which connector you want, your drives dictate where they are connected. Please take some time and read the install manuals. It clearly states in chapter 5 where to wire up each type of drive. There a very, very few exceptions for the newest hybrid steppers but 99% of them wire to the DB25 which is 5v logic like your drive. The headers are open collector connections for servo drives. Many, many people have done the exact same thing you did and while it seems to work on the surface it just simply doesn't. The DB25 breakout board is about $7 on Amazon.

Please add a close up photo of your stepper drive with the model number to your album so others can know what drives you are using.

Let us know how it goes.
cnckeith
Posts: 4646
Joined: Wed Mar 03, 2010 4:23 pm
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Re: New CNC Plasma tablet Build

Post by cnckeith »

create a google photo album of your machine, populate with lots of photos. photos are worth 1000 words, this will help us give you good advice :D
then this thread will become your build thread with all info about the build in one spot. https://centroidcncforum.com/viewtopic.php?f=60&t=6928
guidance is here. https://centroidcncforum.com/viewtopic.php?f=60&t=1043
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
ultramegaok
Posts: 6
Joined: Mon Mar 05, 2018 3:10 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: New CNC Plasma tablet Build

Post by ultramegaok »

Hi Shawn
I finished the wiring from the DB25 as the manual and the distance measured improved a lot, but still not getting the real distance....only in 1 inch the distance is very close (.998) but every one inch increment the distance moves a little bit more. for example at 10 inches move, the readout shows me 10.1254, for 20 inches got 20.2572...... Here you can see my Axis configuration setting. I want to mention that I'm only playing with the X axe, so once that I get this axe to move the real distance I'll move to the next one. The Stepper drive that I got is 2H Microstep Driver DQ542MA....in the google album are the updated photos...
Attachments
IMG_20220812_150858934.jpg
Axis_Advanced.PNG
Axis_Configuration.PNG
ShawnM
Posts: 1223
Joined: Fri May 24, 2019 8:34 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 7804734C6498-0401191832
Location: Clearwater, FL

Re: New CNC Plasma tablet Build

Post by ShawnM »

I'm confused by your choice of breakout boards if that's what that is. This is all you need for a break out board for Acorn:

https://www.amazon.com/gp/product/B073R ... 1965d6ae5a

In your second photo, set your step rate to 100,000.

Try setting your steps per revolution on the drives and the Acorn to 1600 instead of 2000.

Slow down you max rate to 300 IPM and start there.

I'm not understanding what you mean, "at 10 inches move, the readout shows me 10.1254". What readout? Do you mean the DRO reads 10.1254? If you command a 10 inch move in MDI the DRO will read 10.0000. If your overall turns ratio is not correct the axis will physically move more or less then 10 inches but the DRO will read exactly 10 inches.

And please upload a current report from the system so I can look it over.
ultramegaok
Posts: 6
Joined: Mon Mar 05, 2018 3:10 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: none

Re: New CNC Plasma tablet Build

Post by ultramegaok »

I set the step rate at 100 000 and lower the max rate to 300 and is getting very close to the actual reading .... I'm using a Digital Readout DRO from my lathe machine ..... here are some pictures...and the report file too.....
Attachments
report_98F07B2D4600-0422225984_2022-08-13_14-40-33.zip
(2.08 MiB) Downloaded 12 times
IMG_20220813_143813327.jpg
IMG_20220813_143824112.jpg
IMG_20220813_143844549.jpg
IMG_20220813_143900391.jpg
ShawnM
Posts: 1223
Joined: Fri May 24, 2019 8:34 am
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC12: Yes
CNC11: No
CPU10 or CPU7: No
CNC Control System Serial Number: 7804734C6498-0401191832
Location: Clearwater, FL

Re: New CNC Plasma tablet Build

Post by ShawnM »

Ok, well now it’s just simple math to adjust your overall turns ratio to get it dialed in so your move and the external DRO matches the Acorn. It appears you were way overdriving the steppers and they simply couldn’t keep up. You are also assuming that that external DRO is accurate. It’s probably better to adjust your turns ratio using a known distance like using a few 1 2 3 blocks and a good quality dial indicator. But this is an air plasma machine so accuracy to a thousandth of an inch is impossible anyway. :D
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