Mesa based retrofit (analog servos, ethernet)

Hi everyone. I am fairly new to EMC2 but do know my way around electronics and Linux. I am currently working on a project retrofitting a milling machine that currently has a Siemens Sinumerik 810M NC system installed, which we now want to exchange for a modern PC system. The spindle is controlled with a 10V or a +-10V analog signal and also has some other non-critical control and diagnostics signals. The servo drivers seem to be run by +-10V analog signals, though I'm not sure if they are in torque or velocity control mode.

I was wondering a few things, mostly regarding the hardware.

First off, I am wondering what the process for setting up Mesa Anything I/O hardware with EMC2 is. I have searched a bit but the discussion is usually about picking boards and discussing what they're capable of, rather than a general setup instruction. Would it be correct to assume that it's essentially plugging in the boards, flashing the correct firmware and then doing configuration in the PC software?

The hardware I was considering was a 7I93 or a 7I80HD-25 (though I don't understand what the reason for the price difference is) as the FPGA board and then either a 7I33TA or a 7I48 board for the motor controls and something like a 7i37TA for general I/O (endstops, pumps). I picked Ethernet cards instead of the more common PCI cards because I want the flexibility to change the PC hardware more easily if needed, and as it's easier to find and maintain for us. Is this reasonable or is Ethernet not suited for this type of application? I know the 7180HD has a HostMot2 firmware file available but the repository says that the files are 3 years old. (github.com/LinuxCNC/hostmot2-firmware/tree/master/src)

If it really is a bad idea to pick Ethernet cards, what PCI card would be best suited for this hardware? The 5I20 is well supported as I understand, but at the same time it's old. There seem to be arguments both for and against it on this forum.

So the question is generally, are these components reasonable for retrofitting this type of machine with EMC2?

Sorry if I made any mistakes. If you see any, please inform me so I can correct them.

For Ethernet I would suggest a 7I92 and 7I77 or 7I77D
The latest version of pncconf supports this card set
and it gives you a large amount of I/O for the least cost

The main disadvantage d Ethernet compared to PCI/PCIE is that it requires
a Preempt-RT kernel instead of the default RTAI kernel supplied with the current Wheezy based LinuxCNC distribution, but its not a big issue since Jeff Eppler has created a LinuxCNC distribution using a newer debian (Stretch) release and a Preempt-RT kernel:

www.linuxcnc.org/testing-stretch-rtpreempt/

In general older firmware is not an issue as the Hostmot2 Firmware set has been pretty stable for the last 5 years or so +- some bug fixes

Thanks, that's does seem better. Do you happen to know the difference between the 7I92 and the 7I92H/7I92M models?

Also did I understand the setup process correctly? Where on the spectrum between "plug it in and start machining" and "write all the processing logic yourself" would this kind of retrofit be in terms of complexity? Mesa really only supplies capability, and their datasheets don't contain anything in terms of application notes.

Mesa really only supplies capability, and their datasheets don't contain anything in terms of application notes.

That's true, but mostly this is because the actual software parts of the retrofit will be in creating the hal/ini files for
your specific hardware and the tuning the drives, these are not really Mesa specific except for pin names.
Mesa hardware pin names are documented in the hostmot2 manual page
Hal and ini file operation is adequately covered by general LinuxCNC documentation.

As I mentioned, pncconf will create a working hal/ini file set for that card combination, but almost always,
for more than very basic configurations you will have to hand edit the hal/ini files

This means that at least some basic understanding of hal/ini file functionality is needed. I would consider this a necessity
before even considering a retrofit of a servo based machine tool

I have read up on HAL before this and I think it's within my grasp.

As a final (maybe not...) point, does anyone have any experience with running stepper drivers (step/dir) via the 7I77 GPIO connections?

Thanks for the hardware tips. The steppers would be used for a tool changer and since we won't be running high production it should be alright.

The axes are run by velocity control mode servos with TTL encoders for NC feedback. I believe I saw you saying in another thread that this is a relatively easily tunable type of system.