5i25 + 7i73

Reinhard wrote:

The maximum number of step/dir channels on a 7I47 would be 6 (on the 12 TX channels)

I see. So the In/Out direction of the RS-422 is fix. Right?
Seems like I need another 7i47 ...

What about Siko magnetic encoders - do you know that system?
The encoder-head supports two different protocols, one A/B like standard encoders (but less exact) and then a serial protocol, which provides the absolute position data.
I'd like to use that serial protocol - is it possible with the RX-channels of a 7i47?

Depends on the serial protocol, Hostmot2 currently supports 3 absolute encoder formats:

FANUC
SSI
BISS

Thanks for the search tokens - found linuxcnc manpage for the encoders

Is it necessary to flash a new bitfile to get support for i.e. SSI or is SSI a software protocol, that runs with the standard encoder channels?

It requires specific firmware with support for the desired protocol

I see.

and - does it work with a 7i47 or do I need another daughter?

All three supported serial encoder types just require a RS-422 interface
(so 7I35,7I44,7I47,7I52 etc)

Thanks for the info.

So I can buy another 7i47 to get the number of stepper drivers I was looking for and will be fine for the encoders some day?