Button UP:
- On press:- On release:
Button DOWN:
- On press:- On release:
Field position:
- Request:- Reply:- Example: 5 mm will be
Field temperature:
- Request:- Reply (if there is probe connected):- Reply (no probe connected):
Field step:
- Request:- Reply:
Field Sync Absolute (step):
- Request:- Purpose: override current step counter with another step number

Field GoTo Absolute (step):
- Request:
Field GoTo Incremental (step):
- Request when "+":- Request when "-":
Field Sync Absolute (mm):
- See Sync Absolute (step)
- Explanation: We can ask from focuser current position by mm, but we can't ask it to go by mm, only by steps, the application itself is doing the conversion (will be described later)

Field GoTo Absolute (mm):
- See GoTo Absolute (step)
- Explanation: See the one from Sync Absolute (mm)

Field GoTo Incremental (mm):
- See GoTo Incremental (step)
- Explanation: See the one from Sync Absolute (mm)

HW Version and Date:
- Request- Reply:
FW Version and Date:
- Request:- Reply:
The right half is a bit trickier... A will describe it a little bit later

Button start from T compensation settings:
- By pressing it the SteelGo application memorize the current temperature. After >=0.5 degrees temperature change user can press the calculate button and the app will suggest T Coefficient (there is no description on the algorithm of calculation)

Button Enable T Compensation:
- Request:- Reply (if T compensation is disabled):- Reply (if T compensation is enabled):- For writing (disabling):- For writing (enabling):- Note: the number 4 you can see here is related to Select Focuser model drop-down list. The numbering starts from 0 (total - 5 items). More details later. Number 100 is from the Type T Coefficient field. Numbers 0/2 are working like a switch

Field Number of T Samples:
- Request:- Reply:- For writing:- Explanation: 05000 is 16, 15000 is 32, 25000 is 64 and 35000 is 128 samples per second

Button Position Calibration: start:
- From the User Guide it should move focuser to 25,00 mm position (active only if Custom type of focuser is chosen). In my case it is asking to do it manually with UP and/or DOWN buttons. After that calculate button must be pressed. Honestly, this part in User Guide is not very clear to me, will post it here for your analysis

Field Type MAX Trip (mm):
- Request:- Reply:- For writing:- Calculation: If MAX Trip is 28,99, when 2899/0,25040 (taken from Gear Ratio, below) = 11577,47. As far as I understood the result is rounded

Field Type Gear Ratio:
- Request:- Reply:- For writing:
Drop-down menu Select Focuser model:
- There are 5 items in it: SteelTrack NT2, SteelTrack SC2, SteelTrack RT2, SteelTrack RT3 and Custom.
- NT2: MAX Trip 30, Gear Ratio 0,25040
- SC2: MAX Trip 30, Gear Ratio 0,25040
- RT2: MAX Trip 80, Gear Ratio 0,25040
- RT3: MAX Trip 115, Gear Ratio 0,25040
- Custom: It's my case. Why not SC2 if it is designed for my Schmidt-Cassegrain? Don't know for sure, but may be because the focuser I have can't actually reach 30, only 29,49 (on screenshot is a different number because I am playing with it, Gear Ratio seems not to be corresponding to Vernier scale)

Slider Slew Rate:
- Request:- Reply:- For writing:- The range is in between 350 and 1000

Slider Acceleration Ramp:
- Request:- Reply:- For writing:- The range is in between 1500 and 3000

Field Description:
- Request:- Reply:- For writing:- Note: it must 15 characters long! If less - space character must be added!

IMPORTANT NOTE: All the parameters what can be written to the focuser are lost after disconnection. There is a way to save permanently - sendcommand!

If I haven't missed something this is the entire command set. If any questions - just ask!

P.S. There is a hidden command, purpose of which I don't understand at the moment:Reply:

That sounds fairly straight forward, similar to Robofocus command set.

Finished! Hope to see driver soon, without it I can't start using at full Ekos

Ok, my brain hurts when I read 29,89.. I assume it is 29.89... writing the driver now.

What are the physical units of slew speed and acceleration?

EDIT: One more thing, MAX Trip in steps is a custom value you enter that depends on your focuser model? The minimum is 0 and maximum is MAX TRIP ?

Connection parameters? I'm assuming 9600 8N1

My brain hurts too. But I am no guilty! Just in different parts of world different standards of decimal and group separators. In US for example for decimal separation is used dot and for group - comma. In Europe (not sure if in all countries) it is vice-versa. It creates headache with different kind of software...
There are no physical units for slew speed and acceleration as far as I can see from SteelGo application.
If the model is NOT custom MAX trip is a fixed number (I gave the list of models and corresponding values). If focuser is custom it can be whatever is the digital limit of the command I suppose

Ok the important part is the the steps, you said 28.89 ? so it is not whole numbers? or is it 2889 steps? in INDI, only integers steps are accepted. So for 115, it means 11500 steps in total?

28.89 are millimeters. To convert it to steps you divide it by the gear ratio and multiply by 100. Example: 28.99 / 0.25040 * 100 = 11577.47 which is around 11577.

Thanks, one more clarification, if you request Field GoTo Absolute (step), is there any reply? Is there any indication on the port traffic that the focuser is in motion?

No, the only way to check is asking current position as far as I can understand

Need minimum & maximum for temperature coeff and # of samples.

T coefficient range is 0.000 up to 0.999
# of samples is 16/32/64/128