Are there any disadvantages to using Mesa ethernet boards over using a PCI board?

After a two plus year hiatus I've finally found the time to return to work on my Fehlmann CNC.

I've also decided to go with LCNC as I really wasn't at all happy with Mach3. At the moment I'm going to use the stepper motor set-up that I have, but at some point I will switch over to servos.

Clive S has been extremely patient and generous with his time and I think has answered most of my questions, but I just wanted to canvass this forum as to opinions about the relative advantages and disadvantages of using ethernet Mesa boards - I was thinking of the 7i76e - over PCI based set ups - 5i25 with a 7i76. The former set-up seems more straightforward and more flexible to me, but I'm just wondering if it's more problematic in some way.

David

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relative advantages and disadvantages of using ethernet Mesa boards - I was thinking of the 7i76e - over PCI based set ups - 5i25 with a 7i76. The former set-up seems more straightforward and more flexible to me, but I'm just wondering if it's more problematic in some way.

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Both of the above will give you the same results. 5i25+7i76 is for pci for the pcix you would use a 6i25+7i76 these two setups require a DB25 cable to connect the two cards together. ie quite a short distance.
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The Ethernet versions means you can have the PC any distance (less than say about 90mtrs) from the control box with a cat5 cable.

Ethernet versions are 7i76e with spindle control, 7i96 without spindle control ie. no 0-10v, These two cards don't require another BOB.


Ethernet 7i92 does require another BOB as there are no opto's on it but a cheap bob can be plugged into it.

I have used all of the above apart from the 6i25.

If you decide to use servos in the future you can plug another card like a 7i77 for analogue or 7i85 step/dir both with encoder feedback, into any of the above cards.

Edit: TheLinuxcnc version to go for is 2.8 or 2.9 as 2.7 is getting to EOL and things have changed a bit from 2.7 to 2.8

Please note Linuxcnc is a learning curve, I am no expert but I have done a few conversions with Lcnc.

Thanks again Clive, I'm inclined to go along the 7i76e route as it's a bit more compact and can be quickly plugged into different computers.

I take it that only inputs required for this board are the ethernet cable and a 5v power supply? My set up will be using conventional mechanical limit switches, VFD for spindle speed, 3 stepper motors.

It looks like this board can handle a great deal of limit stops - which I may want to try and handle the strange way the vertical axis of my machine can be positioned.

David

Ethernet and a field supply (something around 6V-34V - but check the manual!!!) - you can derive the 5V for the logic from the field supply.

Thanks Doddy - do I need a field supply if I'm not using proximity sensors?

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Originally Posted by Agathon

Thanks Doddy - do I need a field supply if I'm not using proximity sensors?

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Yes. Always RTFM and check any jumpers on the board

Remember the Mesa card can handle 24V for the limit's which is better for noise regection

Ah OK, the 24v is to run the FPGA. A nuissance since I only have a spare 36v regulated supply and the only other 24v supply in the cabinet is AC and unregulated.

Maybe the 5i25+7i76 is a better option afterall. :confusion:

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Originally Posted by Agathon

Ah OK, the 24v is to run the FPGA. A nuissance since I only have a spare 36v regulated supply and the only other 24v supply in the cabinet is AC and unregulated.

Maybe the 5i25+7i76 is a better option afterall. :confusion:

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You still need field pwr with the 7i76. Is the 36v supply for the steppers if so don't take field pwr from that.
what is the 24v AC used for? You could add a rectifier and a cap.

how about https://www.ebay.co.uk/itm/MDR-20-24...QAAOSwbl9dML~L
or
From the UK https://www.ebay.co.uk/itm/20W-Din-R...8AAOSwm5NeGD1b

Edit: You could use 12V field power but if you might go with servos later then 24V would be more suitable.

Right... I began to realise that I'd need 24v in either case shortly after posing.

The 36v regulated supply was bought for this project, but was abandoned in favour of a home built heavy duty power supply, so would be dedicated to supplying the Mesa board - but isn't 36v too high anyway, I think the manual says 32v?

I think one of those little DIN rail supplies would do nicely and so much less hassle than rectifying the 24VAC. Is 1A enough to do everything? Thanks for the links.

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Originally Posted by Agathon

Right... I began to realise that I'd need 24v in either case shortly after posing.

The 36v regulated supply was bought for this project, but was abandoned in favour of a home built heavy duty power supply, so would be dedicated to supplying the Mesa board - but isn't 36v too high anyway, I think the manual says 32v?

I think one of those little DIN rail supplies would do nicely and so much less hassle than rectifying the 24VAC. Is 1A enough to do everything? Thanks for the links.

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When I refired to the 36V I was thinking using a DC -DC buck converter. Yes 36V is too high I would not go above 24V.

2A is nicer.

https://www.ebay.co.uk/itm/MDR-60-24...813c8b4bf5650c

or
https://www.ebay.co.uk/itm/Din-rail-...cAAOSwxlxd3f2c

Thanks Clive - I'm sure there'll be plenty more questions when I get to the installation phase.

Anyone have any thoughts on Mesa suppliers in Europe? I found two:

http://www.shop.cncmonster.de/
http://eusurplus.com/index.php?route=common/home

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Originally Posted by Agathon

Thanks Clive - I'm sure there'll be plenty more questions when I get to the installation phase.

Anyone have any thoughts on Mesa suppliers in Europe? I found two:

http://www.shop.cncmonster.de/
http://eusurplus.com/index.php?route=common/home

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I have ordered from Eusurplus several times 2-3 days to arrive.

For the benefit of others.
https://forum.linuxcnc.org/27-driver...mesa-suppliers

I'm inclined to use Eurosurplus. How did you get on with VAT? I notice that they quote without VAT and now we are about to leave the EU I suppose VAT should be collected by DHL. What a chuffing nuissance.

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Originally Posted by Agathon

I'm inclined to use Eurosurplus. How did you get on with VAT? I notice that they quote without VAT and now we are about to leave the EU I suppose VAT should be collected by DHL. What a chuffing nuissance.

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Nothing is going to change in the next 12 months regarding vat

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Originally Posted by Agathon

I'm inclined to use Eurosurplus. How did you get on with VAT? I notice that they quote without VAT and now we are about to leave the EU I suppose VAT should be collected by DHL. What a chuffing nuissance.

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A very recent purchase...

EUSurplus e-Shop
Thank you for your interest in EUSurplus e-Shop products. Your order has been received and will be processed once payment has been confirmed.

To view your order click on the link below:

<Big Snip>

Date Added: 25/10/2019

<Big Snip>

Product Model Quantity Price Total
MESA 7i76E STEP/IO Step & dir plus I/O daughtercard 7i76E 1 207.05€ 207.05€
Sub-Total: 207.05€
DHL Zone 2 (Weight: 0.73kg): 29.13€
EU VAT (23%): 54.32€
Total + Administrative Fee (payment related): 302.60€

Interesting - when I when to the checkout with the stuff I need there was no VAT, just DHL shipping.

Ah, it does at the VAT once logged-in.

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Originally Posted by Clive S

When I refired to the 36V I was thinking using a DC -DC buck converter. Yes 36V is too high I would not go above 24V.

2A is nicer.

https://www.ebay.co.uk/itm/MDR-60-24.../283552504762?

or
https://www.ebay.co.uk/itm/Din-rail-...cAAOSwxlxd3f2c

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I used one of the 2A units on mine, works great and for £12 you can't argue!

Rummaging through my extensive collection of junk I found this. 18v 2.3A rather than 24v - any good?
Attachment 27121

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Originally Posted by Agathon

Is 1A enough to do everything? Thanks for the links.

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How long is a piece of string.? Nobody can answer that unless they know what "everything" is.? Only you know what you are going to add to the machine and what current each "Thing" will draw.!
However, based on experience I can tell you 1A is on the low side. I'd go 2.5A minimum and ideally 5A to allow for future additions. That said always check the current draw of what your fitting to check you have enough spare capacity.

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Originally Posted by Agathon

Rummaging through my extensive collection of junk I found this. 18v 2.3A rather than 24v - any good?
Attachment 27121

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18V can be a bit unusual to interface to - if you're using the discrete outputs. If you're happy that it's not a problem then fine; I've used 12V - works for my illuminated buttons, most people will default to 24V.

Thanks.

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Originally Posted by Agathon

Rummaging through my extensive collection of junk I found this. 18v 2.3A rather than 24v - any good?
Attachment 27121

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I guess it should work - the Mesa manual says it will sense 5-32V on inputs and switch 5 through 28V on outputs. You'll lose a bit of noise immunity as you're only running at 75% of 24V, but with screened cables & good wiring I guess you'll probably be OK.