As heritage, The device have number "1", so it would parse only commands with format "[1 Xxx]\n". If all OK the answer echoes input command or send some other data, in case of error there's nothing in answer.

All commands of motors' moving have an option -- end-switches check. To do this just ask to move for 0 steps. Answer have format like [1 x ST=y] where x is motor number and y is end-switch position (1 for "-", 2 for "+" and 3 for intermediate position).

List of commands:

[1 0] -- (new behaviour, old was "restart") -- stop all motors, due to working watchdog there's no need to make full system restart. This command have an answer: "Scorpio_0".
[1 1 xxx] -- move focuser (approx. 100 steps per millimeter).
[1 2 xxx] -- move polariser motor.
[1 3 xxx] -- rotate turret 2.
[1 4 xxx] -- rotate turret 1.
[1 6 x] -- turn on (x==1) or off (x==0) relay of analysator magnet and turrets end-switch1 off/on.
[1 7 x] -- move disperser motor to position x (1 - IFP, 0 - Grizm).
[1 8 x] -- change end-switches check between analiser (x==1) and disperser (x==0).
[1 9 xxx] -- change motor's speed. Motor period = 8 * 65535/(xxx + 10) microseconds.
[1 b x] -- change value of PB0..PB3 to x.
[1 l] -- tell amount of steps left.
[1 t] -- show approx. time from start.
[1 w x] -- change stepper diagram to x (x=0..7).

How to change turret's position

First you should move turrets to zero-position end-switch: [1 x 5000] (here and later: x==3 for turrer No2 and x==4 for turret No1). The "zero" position lays between first and last filters. To move into first position just do [1 x -300]. Turret will move to end-switch of stable position. To move further you should turn off intermediate end-switches: [1 6 1]. After that move from end-switch: [1 x -20], turn on end-switches: [1 6 0] and move to next position: [1 x 300].