7i80DB or 7i76E for MH25V retrofit?

Hello,

I'm retrofitting my Optimum MH25V for CNC and want to use LinuxCNC and MESA for a full/dual closed loop on all axis. Right now I'm undecided between two options of board combinations (ignore the price difference for now, please, and read the items in [ ] as optional/planned for later):

- Combo1: 7i76E + 7i85 [ + 7i73 ]
- Combo2: 7i80DB + 7i78 + 7i85s [ + 7i74 + 7i73 + 7i84 ]

What I want to achieve is the following:
- controlled by LinuxCNC over ethernet, this is a must-have
- step/dir servo control (JMC servos 1.27Nm 400w 20bit encoders)
- linear scales (magnetic [or glas], will have to check the signals first)
- spindle control (driven by a VFD with analog 0-10V signal)

Both board combinations are probably capable of achieving this for the beginning.

I want to expand the functionality of the machine later, but without touching the electric control cabinet if possible -- that's when the 7i80DB + 7i74 idea popped up. Some things I want to add in the future:

- min/max limit switches + home/reference switch on all axis
- mobile jog pendant / stationary control panel / [ touchscreen ]
- some security features (e.g. door switches, cabinet closed, etc...)
- modbus integration for servo drivers (e.g. read out torque/load)
- spindle encoder/synchronization (+ e.g. torque/load)
- flood coolant
- [atc]

With an 7i74 I can easily install new modules/stuff with a simple RJ45 cable and a remote control box (e.g. I could wire the all the limit/home switches to a remote serial IO card). Same with a jog pendant/control panel - I just have to plug the RJ45 in.

I just need some advice if my idea(s) are feasible or if manoeuvred myself into a corner of stupid ideas

Best regards,
Pierre

I see. The 7i76 has two 25pin headers, where one would connect to the 7i85 and one to the 7i74. And it also saves some money. That's great! Thank you

Don't forget that the 7i76e has one Smart Serial port of it's own and the 7i85 (if you aren't using the S version) has 5 more. So you likely will not need to get the 7i74.

Good to know! I think a 7i76e & 7i85s will do it for the beginning.

That way I can connect up to two smart-serial remotes - in the beginning just the 7i73 for a jog pendant / control panel. If I happen to run out of IO, I can still add a 7i74 to the 7i76e, later.

Limit switches, reference switches and basic security could be wired to the 7i76e directly, since I might want to install these right from the beginning, anyways.

I think I'll be on the right track with that.

How many step/dir outputs will you need?

3 for the beginning (X/Y/Z). ATC and 4th+5th axis would be nice, but are nor a must and neither really planned for now.

In that case you won't need the 4 additional step/dir outputs of the S version of the 7i85. You will need to weigh for yourself if it will be more valuable to have 4 additional Smart Serial outputs (7i85) or 4 step/dir (7i85s). You will still have the 5 step/dir outputs on the 7i76e.

I just settled with the 7i76e, 7i85s, 7i74 & 7i73 for now (the 7i85s because of my favorite shops availability). I'll just ignore the step/dir/diff outputs on that card, since I probably won't ever need them. The 7i74 is just for easy of wiring - I like the RJ45 plug to plug concept. Thanks for the suggestions and help. Limit/Reference Switches will be wired directly the the 7i76e, since I don't need a remote box for that when I think about it.

I own a Gigabyte Brix w/ a J3455 already (just tested stretch+preempt-rt+uspace on it) and I'm pretty happy so far. the jitter is 30k-100k on both threads - I think that's fine for initial setup. But I need that one for my CNC router (with Windows 10 + EstlCAM) so I need another small PC.

Since the servo drives I plan to use (JMC) support ModBus (RS232) I looked around for some embedded PCs with serial ports. I stumbled over that one (unfortunately only available in german, but you should get the specs): www.ico.de/picosys-2851-embedded-pc-inte...4gb-64gb-ssd--y10018

It has 6xRS232 capable serial ports and dual ethernet. I really like the idea to at least read-out the servo drives and integrate e.g. a torque meter into the GUI. Once I upgrade my spindle motor, maybe read-out the VFD, too.

I also stumbled over that machine: www.ico.de/picosys-2842-embedded-pc-inte...ssd-8x-rs232--y10006 (which is a www.arestech.com.tw/embedded-box-pc-bpc-3030.html)

This one has even more serial ports. Sounds more awesome, but the price difference is 250€. Probably not worth it. What do you think?

The MESA cards arrived. Now I have a hard time to find a bitfile for that particular combination (7i76e, P1->7i85s P2->7i74). Any help/advice is welcome