It doesn't have to be a mechanical counter. The change could be done in the ASCOM and indilib drivers for the EAF and possibly a firmware fix.
I have made three suggestions but none of them has received an enthusiastic response.
1. Use a 32 bit integer, probably best done in EAF firmware.
2. Implement an automatic "Zone" counter, at driver level.
3. Offer a timing belt SCT adapter kit with a 4:1 speed/travel multiple.
Item 2 would increment a "Zone" counter on reset from 60,000 to 0 and would decrement it on reset from 60,000 to 0, Another option could be attempt to simulate a 32 bit integer at driver level, but that could be a bit dodgy.
Item 3 could also be used improve back-end clearance (see image), which is quite tight on my Evolution 8. It would multiply the resistance torque 4x, so that would have to be evaluated. It would be more expensive than the current flexible coupling, but I would buy it.
My guess is that both the ASCOM and indlib drivers are based on the native driver. The parameters for ASCOM driver are same as ASICAP for example.
Meanwhile, I have used the EAF on 2 nights so far and it works well for focusing at any particular mirror position. I think that a range of 15 to 25 turns will cover 95% of my requirements. It will get awkward if one my optical configurations happens to focus near 0 or 60,000.
EDIT: Further to Item 3. There is a question as the minimum number of teeth possible on the smaller pulley (larger shaft), it's probably more than 15 T. This, in turn, affects the size of the larger pulley. There is also the question of whether or not a 4:1 ratio is feasible for a timing belt. If not, 3:1 or even 2:1 would still be helpful.
Edited by Rac19, 23 July 2021 - 06:28 PM.