new PWM settings in GUI

Assembly-manual.md

@@ -568,7 +568,11 @@ How to works
 - **CW/CCW forbidden zone (software endstops),** are values of the range of forbidden zones in millivolts. the entire range of the rotator represents a voltage of 0 to 3.3V. The setting value will appear in the Calibration page as a yellow area at the edges of the range. If the rotator is set correctly, it only allows movement in the direction from the edge to the center. Keep the protection zone large enough to prevent damage to the rotator.
 - **Watchdog speed** is the minimum rotation speed in seconds per one turn, which if the rotator does not reach, it will be stopped by the watchdog. Use a value at least 50% higher than the real speed to avoid false stops.
 - **Motor supply,** is a choice between AC and DC rotator type. The DC type enables the activation of the PWM start-up and run-down ramps.
--  **DC PWM control** activates the PWM ramp-up and ramp-down when using the DC rotator. If you use a rotator without hardware endstops, the destruction of one component (power mosfet) can cause the rotator to crash. Therefore, it is safe to connect one more active element in series (relay intended for the brake). **This setup is highly recomended, see [Connection section](#dc-motor-with-pwm-without-hardware-endstop-safe-mode).**
+-  **DC PWM control** activates the PWM ramp-up and ramp-down when using the DC rotator. If you use a rotator without hardware endstops, the destruction of one component (power mosfet) can cause the rotator to crash. Therefore, it is safe to connect one more active element in series (relay intended for the brake). **This setup is highly recomended, see [Connection section](#dc-motor-with-pwm-without-hardware-endstop-safe-mode).** Turning DC PWM on activates two other settings:
+  * **PWM ramp length in steps of 25ms** + displaying the length of the ramp in seconds, allows you to set how long the PWM control will regulate from 0 to 100% during acceleration, or vice versa during deceleration - **WARNING - a longer ramp may result in passing the end points, it is therefore necessary to set sufficiently large margins in CW /CCW forbidden zone (software endstops). In this way, imprecise stopping will occur more often due to the overlapping of the starting and stoping ramps when rotating through small angles.**
+  * **PWM ramp start distance** the distance from the target azimuth in degrees, from which the PWM ramp starts, the length of which is set by the previous value.
+  * By combining both values, it is possible to tune the PWM sequence so that the rotator stops as close as possible to the required azimuth. <img src="https://youtu.be/1DgsvXVPl58" alt="YouTube video show two parameter settings" />
+  * If there is a need to rotate to a closer azimuth than twice the "PWM ramp start distance" value, there will be a switch from the starting to the stopping ramp halfway through the journey, which affects the stopping accuracy (missing the entire stopping sequence in the combination of time and distance). Therefore, it is better to choose both values ​​as low as possible for your antenna assembly, so that it does not overlap the start and stop ramps.
 - **USB serial BAUDRATE,** is the setting of the communication speed of the serial console on the USB-C connector using the GS-232 protocol. Enabled commands
   * **?** display the IP address of the rotator
   * **R** clockwise rotation