Advanced Search

Hi all! Long time no speak.   Finally, I was able to finish this transition. There is the PR: github.com/LinuxCNC/linuxcnc/pull/4293 Any feedback is welcome!

I don't know if anybody can help but working with Brad Collette a Freecad Developer who has a PR pending for MTconnect. His PR includes a machine simulation which looks much nicer if the machine visulisation is based on a real machine. The model he has is not open source.

I was hoping somebody would be willing to share their model (only looking for basic 3 axis machine)

You can learn more about his MTconnect project here where I interviewed him about it.
youtube.com/live/b_S-p2nylr8

Thanks guys, Please let me know here if  you can help and are willing to contribute a model that will end up being part of LinuxCNC core code.

Not sponsered at all, just Meanwell make well priced power supplies that are available globally.

MAke sure you have the Realtek R8168-dkms or R8125-dkms driver installed for your realtek card. It may fix it.

Those should be fine at 48V, i know mine were fine when testing them, but being used at 36V.
The thing is, the cheap drives i mentioned some posts back have 9-42V written on them, but powering them with 36V will cause them to fail, fairly quickly, as the 42V written on them is the "absolute maximum rating" or the point where they die. Typical or preferred working power supply is written as 24V on the chip datasheet. I have them running at 27V for several years.
Yours are a different type, with output mosfets that are usually rated for 100V absolute maximum.
-
Sorry for this topic becoming to convoluted, so try not to overthink stuff, get some parts, wire, test, make chips, after a while you get a very good idea of what is perfectly fine and what you could do with upgrading.

The supply seems to have protections in place already for this so I'm probably not going to bother but thanks for the heads up

I would expect that adjustable PSU to work just fine for this application. Like I said, I would not bother adding a capacitor. But if you do, don't use the 35V capacitors I suggested earlier, for use on a 48V PSU.

Try to find an Intel network card, look for used 100Mbps ones, all new 1Gbps ones seen to be RealTek.
If the PC has a PCI slot, even real old 10Mbps Intel ones should work.

I think I have a pretty good idea of what I need, but I might switch the LRS to a 48V 10A supply just so that I have room to grow in the future if I want to.

Yes, this is a fact, and the drives you chose should be fine on 48V. 

The drives have a 50V max but if you don't think it'll cause an issue I'll go for it and see.

Dear Colleges I what to share my experience on this topic.

I after several years looking for this card, I get a mesa card,
looks a Clone one, V2. (kind of clone of 7i92) Pls. have a look on picture attached, I get his one because was easy way to get it, at the beginning  I try to purchase the original one but was not available to be send to my county and after, after they were lack on cards, and after they start to shipping to my country but  the shipping cost became  more difficult to get  that original  card, and after I was looking on amazon o other retail pages and then I found this one on aliexpress. I was thinking it was the original but after some research I understood that it  was a clone one of original one. but cheap and easy to get (shipping cost included) and for test propose I run the risk to get it

well now I use it with my PC box and I do not load any other bin file. ( I see on forum load a bin file is not a good Idea).

Supplier support = after the time they send me the card information
Process to make it talk and work with linuxcnc (debian 12). 
1.       Configure the ip on my dual Ethernet port pc box , card ip 10.10.10.10 my pc 10.10.10.11 port 2 and ethercat on port 1.
2.       Install the mesa card utilities
3.       Install the ethernet utilities
4.        I discover the card io setup by maker
5.        I use linuxcnc wizard (PnCConf) with discover option 
6.       end configuration and start running the Linuxcnc
7.        communication with card disconnect issues , solved by disabling the power save option on the realteck Ethernet com card and after not more issue by the moment
8.       If I do not have any other problem I will replace my old and good  PCIe parallel port card that make  my fadal cnc  run G0 at 200 IPM. 
fadal can run up to 600 IPM but this is not my goal to stress my cnc at that speed. ( perhaps I will test it with this new card)

 About Ethercat  servos and I/os card I been testing,  I have  a hybrid configuration with ethercat, and parallel port and this configuration is working but realteck nic is having disconnect issues that the community say the intel nic is the good one for ethercat and servos, and test it with IO ethercat cards and this realteck nic do not notice me any issue, 

 I do not have a pc with intel NIC yet.

Please share your comments and experience.




 

 
 

NWE wrote:

You will get much better speed from your steppers if you power the drives with 48V

Yes, this is a fact, and the drives you chose should be fine on 48V.
Edit:
You can use a 24V power supply and make the machine work and use it daily, later on if you see you might benefit from higher speeds, you can add the 48V supply.

Logthor wrote:

Is it really that significant? Using a 48V PSU vs a 24V psu. Unrelated, but I feel like you may be sponsored by meanwell.


 

No, I can second most of rodw's numbers. I nearly said the same thing earlier and didn't bother, as your original list looked like a good start.

You will get much better speed from your steppers if you power the drives with 48V

The greatest improvement will be that the fast moves between cuts will be faster.

rodw wrote:

1. Doubling the motor voltage almost quadruples available torque
 

No Rod, not always, ONLY at higher RPM, and "higher RPM" for stepper motor hugely depends on size, inertia, inductance...

rodw wrote:

2. Any power supply for CNC can be overrated by about 40% so for 3 or 4 x 2 amp motors a 5 amp power supply is plenty
 

This is OK, but NOT a rule, and it is not overrated, it is underrated.
The only simple general "rule" would be :more voltage = less current, but that does not explain much
There is to much math involved there, together with the above mentioned inductance, etc

rodw wrote:

3, If a drive does not have a max temperature spec, be guided by the temperature the windings start to melt which is typically around 130 deg C but your motors are silent on that too. 80-100 deg C is fine
 

Or simply, if you put your hand on the motor and your skin does not remain attached to the motor, all is good, despite hurting absolutely unbearably to much.
-

rodw wrote:

I can't see where you mentioned how many drives you are using. For CNC all motors are almost never running in unison and requiring full current is rarely needed.
 

Stepper motors will draw the maximum current when not turning at all, but most drives have a setting for it to lower current when idle, usually at half the set current.

rodw wrote:

3 motors at 2 amps = 6 amps. 6/1.4 = 4.3 amp power supply required.As I said a 7 amp power supply is probably cheaper.
 

Don't, this implies it is a rule,it is not.
Stick to underrating 40-50% for 24-48V power supplies, 50-70% for 90-130V, roughly. So the lower the voltage = less underrating.

Noted, I kind of like rodw's idea with the separate power supplies.

Given the number of issues I've seen where people have tried to use 5v plugpacks or phone chargers for mesa cards, the extra $10 is a small price to pay for reliability.

I will probably get that device then.

I can't see where you mentioned how many drives you are using.

I'm using three drives

If you follow my advice and run a higher voltage power supply for motors, you need a seperate 24 volt power supply for field power.

Is it really that significant? Using a 48V PSU vs a 24V psu. Unrelated, but I feel like you may be sponsored by meanwell.