6i25 + 7i76 plug and play, card not showing and no tabs in pncconf.

BTW, just because I want to learn.
If the 7i76 step output has a 75 ohm impedance, does that mean that the 5 V is inside those 75 ohm and that the ouput from the 7i76 will be only 4 V when connected to a 300 ohm load?

Yes that's correct

No driver has 0 output impedance so if you have a 5V power source the load voltage will always be less then
5V if the load has non infinite impedance.

The 7I76 outputs have added series resistance to protect them from short circuits.
This and the internal driver impedance add up to ~75 Ohms differential

I would always choose differential mode when possible as it has much better noise immunity

This post is just to say thank you for the excellent support, and for an excellent product. So far I am very happy with my Mesa cards.

I am looking at what I need to do for watchdog to have a safe and professional system.
I read that there is a watchdog in the 6i25 card that just works, auto petted by the hm2 driver without me doing anything extra.

What about if the computer hangs? Should I use the LinuxCNC component in some internally petted way or will that just hang with the computer? Is there a need on Linux?

Also I would like two or three analog in. I thought the 7i76 and 7i76e was equivalent, I guess I did not do that research well enough. Bummer.
Did anyone get the headphone jack to communicate with LinuxCNC? Other easy tricks to get analog?

Best wishes
Patrik

If the computer hangs ( and stops accessing the 6I25 periodically ) all outputs will be disabled
In addition, the 7I76s field I/O section has its own watchdog (with a fixed 50 ms timeout )

In addition there is a LinuxCNC watchdog component that you can add to your hal file.
Unlike the hardware watchdogs, it does require working threads to timeout, but it
can be used to check things like user interface health and shut down the low level hal operations
if a fault is noted.

The 7I76E field I/O section is identical to the 7I76's so it has identical input options

Thanks, I think the Mesa watchdogs will suffice. I feel it is quite safe as it is.

GREAT news about the analog in even on the 7i76, I found the section in the manual on page 14. I was tricked because the analogs are not mentioned in the first general section in the 7i76 manual, but they are in the 7i76e manual.