Pedal as modulation source

[vlazzarini]

Hi,

I have a question about the expression pedal source in the mod matrix.

There are two source items:

- foot
- expressn

In the manual, they are marked as foot pedal and expression pedal.

I placed a TRS cable in the CV/pedal jack and connected it to a guitar volume pedal and I can get it to control a parameter via the "foot"
option but not via expressn.

I can also control volume via the global setting.

My question is: what is the expressn option for? Where does that signal come from?

Thx

Victor