Advice on component selection.

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29 Dec 2014 07:03 #54350 by NeoTech
Hi!.

Well i have been lurking here but usual lives on cnczone - but it seems its here i should be for this. =)

My basic hardware setup looks like this
PC: www.alibaba.com/product-detail/Super-hig...le-3_1668209218.html
Its an Core i5m + 8gb ram and 30Gb mSATA/SSD

I've choosen to go with these in my conversion, in a basic 3 axis setup for now; www.hzmgdj.com.cn/product/464991883-2132...otor_controller.html

Here comes the hoop jumping i guess.
Thos drivers support both step and analog - and i wanna go the MESA route.
So i got some help from a gentleman on youtube that suggested this card would work.

7i90HD for maincard.
7i48 as servodrive.
and a 7i37TA for buttons and such.

The machine im gonna drive is an old Aciera F3 thats gonna get some adapters and belt drive basicly.
But my question is, would those 3 mesa cards work well together, can they be easily configured through that magical wizardy tool - if not, should i swap out the 7i90 for a 7i43-P ? -U? -U-4?
would it be "better" driving these motors with a step/dir approach instead - they support 32 micro steps - this is a precision question i assume..

- There is a ton of components to choose from - and sofar my cnc adventures is a BF20 with chinese stepper drivers and Mach3.. that was not fun. At all.

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29 Dec 2014 07:43 #54352 by NeoTech
So an alternative could be a 6i25+7i76 on that board utilizing a Mini-PCIe -> PCIe adapter.. If that would be easier to setup i guess.

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29 Dec 2014 15:06 - 29 Dec 2014 15:12 #54356 by emcPT
Hello,

I will honestly, although I have a commercial interest in recommend this to you, to choose differently:

3 Argons drives
+
1 5i25 or 6i25
+
7i77

If you require many IO or using a full button interface, the you would have acquire another inexpensive board.

With this combination you can use full encoder feedback to your PC (linuxcnc will know where the machine is all the time) and the hardware is minimal. Also the drives are made in Europe and they are very good. It is also a know configuration, so that when you need help there is a lot of info. In my company we changed more than 4 machines with this combination and things really work well.
What motors do you have?

I would recommend my site, but you are obvious free to buy elsewhere: www.eusurplus.com
Last edit: 29 Dec 2014 15:12 by emcPT.

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29 Dec 2014 19:23 - 29 Dec 2014 19:30 #54361 by NeoTech
So i guess this will be a ... really dumb question..

But sure Argon drives looks nice, even tho they are bit expensive compared to the 1 kW motor and driver combo i've found earlier. (And i cant seem to see if you have / sell 1kW motors).
To the question. why would i run a 7i77 analog servo card when the Argon drives support RS-485 interfacing. Shouldn't the 7i74 card be more suitable for the Argon drives?

Or am i missing something here.. Feels like im missing something here.

On other note, so running buttons, would be better to make use of the parallel pin-out on-board and run like the 7i43 and an IO card that way?
Last edit: 29 Dec 2014 19:30 by NeoTech.

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31 Dec 2014 05:52 #54437 by emcPT
The RS-485 on the Argons is currently only to setting the drive parameters and to monitor it. It would be possible to control the Argon though it, but currently is not possible and there is no motion generator using the RS-485 protocol (as far as I know) for LinuxCNC.

The 7i74 is intended to IO.

Regarding the parallel port, my opinion is to completely forget the parallel port and use 24VDC for IO, that is possible with several boards, including Mesa ones.

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06 Jan 2015 01:54 - 06 Jan 2015 01:55 #54598 by andypugh

So i got some help from a gentleman on youtube that suggested this card would work.


That would be me. I don't know if I have been accused of being a Gentleman before :-)

LinuxCNC is based around the idea of doing the motion control inside a PC. This means that you can see what is going on and that can be very useful for fault-finding and tuning compared to using smart drives that do the motion control internally.

This typically means using analog-input velocity-mode drives, but not always. It is possible to achieve the same result using a step-dir stream as a velocity command, and there is nothing inherently bad about using step-dir servos as something that the system sees as stepper motors, except that the motion-controller inside LinuxCNC knows a lot more about what you are trying to do than the drive ever can (there is no scope for velocity-feedforward in step-dir mode, as an example)

However, I don't think that a mini-PCIe to PCIe converter will work. Those slots are typically only compatible with WiFi cards.

That is a very cute PC board, but unless you have already bought it, there may be better options.

In practice the performance of the Parport-connected Mesa cards is no better or worse than the PCI ones in LinuxCNC applications though. I run both in my workshop.
Last edit: 06 Jan 2015 01:55 by andypugh.

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06 Jan 2015 04:18 #54612 by NeoTech
Yeah i actually have two of these mainboards running Realtime kernel figuring out its latency atm its running 2<alot of numbers> something consequently and rarely spikes over 4<alot of numbers> - so seems to be fairly responsive actually.

And you are correct, the MiniPCIe on these cards are for Wifi and GPS module.. and thats it. It will not work with anything else.. i got an adapter and tested some PCIx grafix i had lying around.

I was starting too oogling the 7i80HD-25 card actually. But it seems to be a hassle to configure as well for a total newb.

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06 Jan 2015 04:28 #54614 by andypugh

I was starting too oogling the 7i80HD-25 card actually. But it seems to be a hassle to configure as well for a total newb.


Indeed, I wouldn't recommend it for someone in your position.

At this point I would say that you should see what motors and drives you can find, then choose the interface hardware.

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06 Jan 2015 04:32 #54615 by NeoTech
I will go with Granitedevices Argon drivers what it looks like. And for motors - not found any suitable yet, but still oogling ebay and alibaba.com. =)

Seems like the argon drivers is good universal ones and tad bit expensive tho i might say - but sure i will prob. not swap em out for a long time anyway.

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06 Jan 2015 05:02 #54616 by NeoTech
So cheapskate version, 7i90HD + 7i48 + 7i37TA - seems to be a economical way to go actually. And supported in 2.6

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