G'day from Australia - Mesa board selection advice. Please help.

Most people's are blende by ethernet theoretical speeds. And as things mostley work somehow they never have to look in the details. Fx. A switch has to decide if a message arrives on one physical port on with physical port it should send it out. Some do much more before send it.. Or if there is traffic on several ports, a cheepo one has not the resources to send it. Or one other device is always using broadcasts. And there are often network organizing protokolls on their way...
So in realtime world you avoid lots of trouble by using a one to oneconnevtion

Mike_Eitel wrote: Most people's are blended by ethernet theoretical speeds. And as things mostley work somehow they never have to look in the details. Fx. A switch has to decide if a message arrives on one physical port on with physical port it should send it out. Some do much more before send it.. Or if there is traffic on several ports, a cheepo one has not the resources to send it. Or one other device is always using broadcasts. And there are often network organizing protokolls on their way...
So in realtime world you avoid lots of trouble by using a one to oneconnevtion

Mike_Eitel wrote:

Mike_Eitel wrote: Most people's are blended by ethernet theoretical speeds. And as things mostley work somehow they never have to look in the details. Fx. A switch has to decide if a message arrives on one physical port to witch physical port it should send it out. Some do much more before send it.. Or if there is traffic on several ports, a cheepo one has not the resources to send it. Or one other device is always using broadcasts. And there are often network organizing protokolls on their way...
So in realtime world you avoid lots of trouble by using a one to oneconnevtion

Hi RodW,

How are you going up there in Queensland? I hope everyone there is coping in all this insanity. I really appreciate the offer of help. While I hope I don't need to pester you, it's nice to know it's there.

Also, thanks for the info re: 7i76e + 7i78. I'll look into that. So far I have been looking for a "simple" solution, so I started by looking at a single card like the 7i95, and I must say that the info isn't always clear on what each card DOESN'T have. I must've missed the lack of VFD control part on the 7i95. Thanks for setting me straight!

While I've read about a few boards, there are always the niggling questions like:

"Is this the best combination of Mesa cards in terms of both cost, and/or performance?"
"Has anyone used this particular combination before? Is it going to be reliable?"
"How sure am I in my interpretation of the facts presented?"

I'm a little ashamed that I don't find answers to these questions easily, and I keep hoping that someone will put a card comparison tool on Mesa's site with nice little tables showing what is and isn't included. I'm honestly starting to doubt myself. o_0

So I'm sorry if my neuroses lead me to asking simple questions with obvious answers. I've never built a CNC before, and while I'm no stranger to plugging boards together, I just want to get this right before I order it.

The ODroid looks amazing, but at this point, I have a few too many PCs laying about so I should put a couple of them to work before buying any more.

Anyway, I'm a long way from a finished CNC at this point, so any sage wisdom advice, recommendations, or just stuff I might want to avoid, is always welcome.

I'll keep you posted,
Hamish.

Hi all I have not responded to directly, (Mike/Aciera)

I'm sorry, but I've had a busy day and can't respond to you all as I'd like. Thanks for the information.

I get that there's a lot going on in the network when switches and other gear are used as intermediary devices, and that theoretical speeds are almost never achieved due to the overheads and issues at each layer of the TCP/IP stack. However, I have no idea of the bandwidth required for reliable CNC functionality.. but I recall correctly (It has been a while) Parallel ports had bandwidths of only 2.5Mbit.

That seems a long way short of most 100Mbit connections, although I must confess I'm not entirely sure how fast the ethernet interface is on Mesa boards, Is it only 10Mbit or something? I couldn't find that specification in the 7i76e manual.

Anyway, thanks for the responses from you both.

Kind Regards, and good night!
Hamish.

I know there are a great many people who ultimately want to control everything from their phones or at least sitting in their comfy chairs. But seriously your talking about a CNC Router, how are you going to set up your jobs when your sitting in your office?

Believe me, there is going to be a steep enough learning curve ahead of you without trying to stretch the envelope. So I would recommend to heed the guidelines and save yourself a lot of headaches.

I for my part always try to keep the data lines as short as possible. But maybe that is just old fashioned and chicken.

:laugh: