HAL for open-loop encoder homing

Hello.
I am using a Mesa 5i25/7i76/7i85s setup with LinuxCNC 2.9.4 on a milling machine.
I am using an open-loop control configuration. The axes are equipped with Chinese Sino optical linear scales, which I want to use for precise homing. AI helped me write the HAL and INI files for this setup. Before I added the BACKLASH parameter to the INI file, the system performed homing correctly and accurately using the scales' index mark; however, after adding BACKLASH, accuracy and repeatability were lost—sometimes it was accurate, other times not. I have attached the HAL and INI files. Could you please advise on how to fix this issue?
I read that this can be resolved using firmware that supports step/direction indexing, but I don't know where to download it.
Thank you.

Is this open loop in the sense that you do not actually use the encoder
or its index for position feedback?

Yes, I use the encoder solely for the homing procedure using the Z-mark on the Sino linear scale.
First, the axis moves to the inductive sensor, and then a precise homing sequence is performed at a lower speed using the encoder's Z-mark.

Alexf2a wrote:

Alexf2a post=350204 userid=28355

I don't see any 5i25+7I76+7I85S firmware images with step/dir index
but I can compile one in the next day or so if you want to try it.

 

5I25 configuration for 7I76 +7I85S with Step/Dir index for
Step/Dir channels 0..3 (7I76)  on 7I85S encoder index pins 0..3

That is 7I85S encoder inputs 0..3 has shared encoder and stepgen
index function with the stepgen index function applying to stepgens
0..3 (on the 7I76)