I was experimenting with the screen position feature for the first time so I could use my screens with a sun-controlled automation in Home Assistant.
I’ve run into the following issue: there is a small difference between the time it takes for the screens to move up and the time it takes to move down. As a result, the position gradually drifts. The more I open and close the screens, the more they remain slightly open when the position is reported as 0%. This small error accumulates with every movement.
I noticed there are settings to adjust the timing for normal blinds, but unfortunately these don’t seem to help in my case.
Has anyone else experienced the same problem, or found a solution?
Gravity has an interesting affect on lifting and dropping things, someone should write a paper on it
Seriously, the only blind motor system with an encoder for position is the Lutron range, but that’s for a patent against it, which is why all other motors are timed only.
There are RS485 controlled motors, but I don’t think they have encoders.
If you can think of a solution that bypasses the “Hemline Accurate” patent limit, you’d make a fortune.
I’ve found the solution for timed shutters / blinds is to fully retract them to reset the timer.
I’m going to assume that your timed your blinds by fully deploying them, then timing how long it takes to retract. (I normally advise to add 10%)
I’m glad to read that I’m not alone with this issue!
I wonder how accurate the VMB2BLE measures time… …
Just like you, I control the blinds using HA, when the sun is on the window and some other weather-based conditions are met, the blind goes to given position.
When the sun is out of the window or weather conditions are not met, blind goes back to position 100%. Unfortunately, that is never fully retracted.
The solution proposed by PrzemoF, once in a while reset the position is NOT possible from HA because the blind is already at 100%, at least according to what HA thinks.
I worked around this using the “Immediately up” half an hour before sunset. The module will drive the motor for programmed time, but since the blind is almost in, it will be fully in now. Ready for the next day.
