Verify my Mesa selection

Hello,

I am in the process of ordering the necessary components to retrofit my CNC mill. I just worked my way through the mesa selection guide and worked with the configuration tool. Now I would like your help verifying my selection so that as a beginner I don't make a costly mistake that could have been avoided.
The requirements are as follows:
3 analog servo drives with feedback from glass scales
1 Spindle vfd
3 mpg handwheels
34 digital inputs
18 digital outputs

At some point I would like to add physical buttons to the operators console, which would be realised with an 7i73 in the console.

The PC is in the operators console as well, and can only be connected to the mesa cards via ethernet.

In another post tommylight suggested I use the 7i97t, which can support my servomotors and the mpgs as well as a few inputs. Ideally i would expand this with a 7i76, however that is not available for me in europe.

Following the guide I came up with a different setup. As FPGA card I could use 7i96s and then connect 7i77 with the 25 pin connector. That leaves the smart serial connection for later use with the 7i73.
7i96s: Main FPGA board, controls spindle, 3 MPGs(6 inputs), 5 inputs, 6 outputs
7i77: controls the servo motors, takes the feedback from linear scales, 32 inputs, 16 outputs
7i73: keys and encoders on the operator control

so that should have me covered, or am I missing something?
 

Why a 7i96 and a 7i77? Can't the VFD be set up to accept an analog speed command, and therefore controlled by one of the free axis on the 7i77? These are both FPGA cards, so you end up with a lot of reduntant processing, and also a lot of unused features on the 7i96.

Are all your outputs on the same voltage? I ended up short of 24V outputs, as I had to put one rail of the 7i84 on 5V.
Good choice on a 7i73 in the user interface panel is a huge time saving in wiring reducing the wiring from the User interface down to the electrical panel to a single Cat 5E, plus one discrete for the E Stop.
Are you not using encoders for Jog/spindle/feed overides? These are slow enough to use normal pins and software encoder.

Have you considered 7i97/7i84/7i73?

Another option is the way I did it on my lathe. I split up all the functions with:
7i92 for the FPGA, plugged straight into:
7i85 interfacing the axis and spindle encoders, and providing 5 channels of RS-485 SSfor:
7i84 I/O (I might need to add a second one)
7/83 Analog servos
7/73 User control panel.
That leaves two spare RS-485 SS ports, so it will be easy to connect in the second 7i84 (once I find space for it in the electrical cabinet), and maybe a second 7i84 for jog wheels down on the apron.
 

First of all thanks for the quick reply.

The setup with 7i97t with 7i84 would be ideal, however the 7i84 with sourcing outputs is currently out of stock everywhere I look. The spindle vfd takes a 0-10v signal and can therefore easily be controlled with one of the 6 axis outputs. I actually follow your Schaublin retrofit and that's where I got the idea for the 7i73 in my control cabinet. This can support physical keys in a matrix and also the encoders for Spindle/feed/jog so that's really good. I'm not satisfied with the cards in my electrical panel as well, but selecting from the available components this seems to work. Also, maybe in the future I'm gonna add a 4th axis to this machine and I'm not sure which type of motor I'm gonna use then, but having the 7i96 would leave the possibility of using a stepper or a servo for that.

Also, for the outputs i really only need the analog signals for the drives and vfd and digital 5V outputs. Anything that is not 5V has its own little relay in the cabinet.

A whole 7i96 is a lot of card, for the potential expansion of a stepgen, maybe in the future. All those FPGA cards have a 25 pin expansion slot which we mostly dont use (P1 on the 7i97).
I am pretty sure you can add a stepgen onto a couple of those pins with a bit of playing around in the MesaFlash utility. It looks like you could also use that to hook in a second SS for the 7i73.

Peter (Talla83) has done some excellent videos on how to edit the bitfile for the mesa cards, such as this one (In german, but Youttube does good tranlations subtitles.


 

Alright so it turns out I can use sinking outputs since all the outputs go to a relais board and I can just give the common on the coils +5V and then switch them by sinking. That means I can use the 7i97t as my "main card" with ethernet connection to the pc and the 7i84D for I/O. The 7i73 in the control cabinet could then be connected using the adaptor talla83 shows in the video, right?

I think with that I am all set.
7i97t: connection to PC, 3 analog axis outputs, encoder feedback with linear scales, spindle output, 3 handwheel mpg inputs(uses 6 inputs), 10 inputs, 6 outputs
7i84D: 32 inputs, 16 outputs

Note that 7I84s should become available in a week or so.

It shouldn't matter either way. I just want to know if this setup will work fpr my needs so I can go ahead with ordering the parts.
 

That is a good board selection for your machine. It is the modern version on the 5i25/7i77/7i84 which is working well for me on the Maho.

You list connecting your three MPG's to the 7i97 using 6 inputs. You could  do that, but will have three unused high speed encoder inputs on the 7i97, which you could use. However, in practice, your MPG's are probably on the user control panel and will be more practically wired into the 7i73, rather than running those three cables back down to the electrical cabinet to the 7i97.

Yes, you can make up a Talla83 board to add a couple of extra SS ports. You will need to edit your bitfile for that, but Peter describes that. This would give you two ports, one for the 7i73, and leaving one for the pendant.

Have you seen "Toms Pendant" which Talla83 made with a guy called Tom? I had already made mine when this came out, but it is way better than mine.

talla83.hier-im-netz.de/hp_inhalte/tshw/TsHW_V3.pdf
www.thingiverse.com/thing:3684937
github.com/talla83/tshw_2022
 

  Thanks for your help.

The mpg handwheels on my particular machine are mounted on the apron and their cable already runs to the electrical cabinet. For manual type work which is a lot of what this machine will see, I reckon this will work very well