First of all we'd like to thank you for your preference for BITalino. Currently OpenSignals only allows manual control of the PWM output using the slider in this portion of the UI:
Nevertheless, using our APIs, you can easily develop your own code to control the PWM dynamically based on one of the inputs (or your own rules). Se this example for the Python API:http://bitalino.com/pyAPI/#bitalino.BITalino.pwm
An important details, as for sure you are aware, is that the analog inputs have 10- or 6-bit resolution, while the PWM output has 8-bit resolution. If you write your own code, you'll need to take this into account.
Hope you found this information useful to help you complete the goals you're pursuing. In case you have any further questions we can help with, just let us know.
The BITalino Team