LinuxCNC with Mesa 7i65 and 6i24 FPGA

So just some background for those that aren't aware.

The Mesa 7i65 is a 8 axis analog servo card that supports TTL or differential encoder inputs.
The Mesa 6i24 is the PCI-Express (PCI-X) version of the 5i24, with 50 pin IDC connectors for I/O.

First post, so forgive my knowledge gaps.

Question 1.) Can the 7i65 and 6i24 work together with LinuxCNC, or would I be better off using the seemingly more popular 7i77 for analog servo control?

Question 2.) I have Yaskawa Sigma 1 servo drives (SGDB) I want to operate them in speed/velocity mode with LinuxCNC.
Sigma 1 Yaskawa SGDB drives in velocity/speed mode produce Quadruple Differential (RS-422) encoder output.
The Mesa 7i65 supports RS-422 differential encoders so I believe it should work with my Servo Drives.
Does that sound correct?



Question 3.) I have 50 pin IDC Ribbons where the old controllers 24v I/O connected. I'm hoping I can directly connect those 50 IDC ribbons into the 50 pin IDC connectors on the Mesa 6i24. Is that going to work?

6i24 Image

Thanks in advance!

1. Yes, a 6i24 and 7I76 can work together
2. Both the 7I65 and the 7I77 have differential encoder inputs so should work fine
with your drives
3. This depends on the pinout of the 50 pin connectors, all of our 50 pin I/O FPGA cards
have a pinout the matches OPTO22-Gordos etc 24 channel I/O module racks

A 6I25/5I25/7I92 + 7I77 would be a more common card set for this type of application
(perhaps with a 7I90HD added for 50 PIN I/O if your pinout matches)

I run my lathe with a 6i24, it has a very good ratio of price to IO points. But it does need daughter-cards in order to be useful. But the same is true of all the PCI cards.

I used it because I needed the 7i49 resolver interface.

I ended up going with a...

6i25 FPGA Card
7i77 Analog Servo Card
7I84 for 24v Digial I/O

I realized the 6i24 wouldn't work because it's not made for 24v I/O inputs (from what I could tell)

I may need more I/O - not exactly sure. Can you daisy chain 7i84's together?

benmoto wrote:
I may need more I/O - not exactly sure. Can you daisy chain 7i84's together?

You should have also gotten a 7i74 as that would allow connection of 8 more 7i84 or similar.
I tend to use that in all my retrofits. In one retrofit i used it to wire directly 5 serial absolute encoders, and PCW made a firmware for that, thank you very much, it is in use every day for nearly 2 years now, and it has a 7i70 and a 7i71 also wired to it.

benmoto wrote: I realized the 6i24 wouldn't work because it's not made for 24v I/O inputs (from what I could tell)

The headers on the 6i24 are for logic-level inputs. You would use daughter cards to choose the required voltage and current levels to be driven, and in which direction. For example the 7i37TA

I may need more I/O - not exactly sure. Can you daisy chain 7i84's together?

Don't forget that there is some IO on the 7i77, so together with the 7i84 you have a fair bit of IO already.
The 6i25 has a second header that can be connected to another DB25 card. As has been mentioned, one possible DB25 card is the 7i84 which can connect 8 more smart-serial cards.