Foot switch can be assigned to CC values (1-95), Arp Switch, Motion Sequence Switch, Play/Stop, Live Set+, Live Set-, or Octave Reset.

None of this would result in a tap tempo.

There are other options which would not involve a foot switch. Just rolling past those ...

You cannot make the foot switch result in a tap tempo unless you could hook a foot switch to an external device (not MODX) and tapping the foot switch for that external device would adjust its tempo and then that external device would either send MIDI clock or send "clicks" and then have MODX slave to the external clock or MODX follow the external "click" fed in through the A/D input.

I want to globally assign a footswitch to control tap tempo. This to sync FX/arps to whatever tempo the band is playing on the fly.

I've been unable to figure this out and inclined to think it is not possible. Anybody here done this successfully? Thanks.

There are Foot Switches you can buy that can be used for this purpose. They connect to the 5-pin MIDI IN and they generate MIDI Clock.

Link: Polytec One.2

Extra Credit: Alternate Methods
The best way to use devices that have their own tempo (like arpeggiators) is to have a clock that can be *heard by all the musicians in the band*, then syncing your instrument to that audible clock source. Tapping the tempo in order to correct your instrument’s Arpeggiators to the tempo of the band is a full time job. You need to setup a “conductor”.

The reason orchestras have a Conductor (with a dress tuxedo and baton) who stands in front of the ensemble where everyone can see them, is so that no one person has to sit there and constantly interpret tempo for someone else. Everyone in the band collectively is following the conductor.

Some band’s attempt to solve this by giving a click to the drummer and everyone follows the drummer... this is not foolproof either. They wind up blaming the drummer when the band is completely lost. Sooner or later an entire Beat gets “lost”.

Imagine if only the first violinist could see the conductor, and everyone else has to follow the first violinist. Not ideal either. In fact, it will not work! Take a hint from this...

Ideal or better, would be a clocked device that everyone in the band can hear and play along with. If you are the only one attempting to adjust your technology to the tempo... ? How are you going to play?

If you have a device that generates tempo and you can feed it into the band’s monitors, then you can feed that clock directly to your MODX and have it automate the tempo for the entire band. In order to use tempo driven devices like Arpeggiators, you need a reliable clock source, where its everybody’s responsibility to adjust to the tempo.

All the musicians have ears, when Arp joins your band, you must make allowances for this huge technological step. Arp (while he can play the most difficult passages correctly every time, and he knows literally thousands of riffs in all keys) cannot hear. And while his timing is impeccable, he cannot hear on his own. And the prospect of you constantly tapping tempo, will not only NOT be fun, you’ll soon discover its a constant, thankless job

I recommend an external clock that can feed MIDI clock to your MODX, and you need an audible output that can feed the band’s monitors. Share the TEMPO responsibility with the entire band. If money were no object: you’d solve this with a killer monitoring system.

Alternatively, feed an audio signal to the MODX A/D Input and set your MODX MIDI SYNC = A/D IN... you can feed tempo by placing a mic on your drummer. This requires practice, and is a second choice simply because of the discipline it requires. But I’d try this over tap, tap, tapping tempo constantly.

Hope that helps.

There's been a firmware update that changes this answer a bit since the last update. Since this thread comes up first when I search, I'm updating ...

Source: https://www.yamahasynth.com/learn/news/montage-modx-synthtips-how-to-change-the-foot-switch-assignment

The Foot Switch is assigned under UTILITY. This means it will work the same way in ALL Performances. MONTAGE OS v3.5 and MODX OS v2.5 add the ability to control Tap Tempo with the Foot Switch.

Previous firmware did not allow for you to use a standard momentary footswitch plugged (like an FC5) into the footswitch connector to control tap tempo. Now this can be done.

Source: https://usa.yamaha.com/products/music_production/synthesizers/modx/update.html

Tap Tempo assign to FS2
Foot Switch assignments are globally set under [UTILITY]/Settings/MIDI I/O. Here, MIDI control numbers and hardware-specific controls can be assigned: Arp Switch On/Off, MS (Motion Sequence) Switch On/, Sequencer Play/Stop, Live Set +, Live Set – and Octave Reset. With MODX OS v2.5, Tap Tempo is added. This is a nice feature for live performance - making it easy to control the tempo of the Pattern Sequencer or set a tempo delay effect to sync with a live band, all hands-free.