Thanks! but I still have no success to make it work...
I have copied a post by
@philipacamaniac (I don't know how to make a link to a post). This may help and the bit in
bold is very important.
Many new users get confused about the external footswitch and pedal configuration options. Here's a quick primer. This is all in the manual but a second read sometimes helps.
There are 4 pedal jacks that can be used with either a switch or an expression pedal. These 4 pedals are assigned under I/O: CTRL.
There are also 12 "external controllers" which have a confusing name. The external controllers are strictly for assigning modifiers to parameters within presets. These external controllers can either have a MIDI CC source or one of the 4 pedals as a source.
For convenience, Fractal assigns a default of PEDAL 1 - 4 to EXT CONTROL 1 - 4. This means that pedals you plug in to a new AX8 are instantly available as External Controllers 1 - 4 for use in presets (for wah or volume in some of the factory presets).
If you want a Pedal to have some other global function under I/O: CTRL,
you need to first unassign that pedal from its default assignment as an External Controller. Each pedal can only have one function in I/O: CTRL, so the first function in the list seems to take priority. I don't know if this is a bug or intended design, since the pedals can be assigned to multiple items (they just won't work).
So for example, if you want to use Pedal 3 as a tap tempo switch, you have to assign TEMPO TAP on that screen to PEDAL 3, but you also have to set EXT CONTROL 3 to anything other than the default of PEDAL 3. "OFF" is usually the best choice.