Hardware Modification / Rotary Pot

Well, I think it is not that easy.

The switches are tied to a matrix drived and scanned by digital IOs, but a pot should be tied to the analogue input of the ADC, and supplied with some regulated voltage.
There might be unused ADC inputs, but they are probably grounded, so you probably have to seriously modify the PCB and solder to the MCU's pins...

Using trims as "analogue" input is easy, however using that value for limiting a channel value is challenging.
You could easily use it for scaling, but I haven't found out yet how to use it for limiting...

the switches are actually not part of the button matrix, but none of the switches are connected to pins that can be reconfigured for analog, so it isn't possible to replace them with dials. There are no pinned-out pins that would be capable of this, so adding a dial would involve some very delicate soldering work.

to be clear you want to take the input of a channel (say a virtual trim) and use it as the max value for another channel?

I can't think of a way to do that with the currently available curves, but I could probably add a new capability to support it. file an enhancement request on bitbucket and I'll give it some thought.

I've spent some time looking at this, and I don't see an easy way to implement it with our current mixer as a curve. However, I was almost able to get it to work properly by chaining mixers together. Here's how:

we have a stick input: thr
we have a limit input : lim (which youcan define using trims for instance)

we want:
if (thr < lim) then output = thr
if (thr >= lim) then output = lim

We can achieve this with the existing capabilities as follows:
VirtCh1 = thr - lim
complex mix:
page1:src=thr
page2:src=lim,scale=-100,mux=add
OutputCh = VirtCh1 * (if VirtCh1 <= 0 then 1 else 0) + lim
complex mix:
page1:src=VirtCh1
page2:src=VirtCh1, curve = zero-max, scale=-100, offset=100, mux=mult
page3:src=lim, mux=add

This actually works well, except that the mixer applies a cutoff of -100 to 100 after each operation. so if lim = 80 and thr = -40, we end up with (thr-lim) < -100 and it gets truncated, making the code not work as expected

So we can fix it as follows:
VirtCh1 = 0.5*thr -0.5*lim
complex mix:
page1:src=thr, scale = 50
page2:src=lim,scale=-50,mux=add
OutputCh = VirtCh1 * (if VirtCh1 <= 0 then 1 else 0) + lim
complex mix:
page1:src=VirtCh1
page2:src=VirtCh1, curve = zero-max, scale=-100, offset=100, mux=mult
page3:src=lim, scale=50, mux=add
Then set a final scalar (on the limit page) for OutputCh to 200%

Here is a demonstration model.ini that sets THR as the input (Ch1), AIL as the limit (CH2) VirtCh=Ch3, OutputCh=Ch4.

I don't see an easy way to implement this as a push-button solution, but I may be able to build a template that will at least do an initial configuration.
I will also look into whether I should not truncate the intermediate stages when building a mixer. I have a feeling there is a reason I did that, but maybe not.

HornetMaX wrote: Honestly I haven't played with Deviation mixer stuff at all hence I may just be talking garbage here, but from what I've read in the manual, wouldn't the easiest way to implement a limiter (i.e. an input limiting the max output of an output channel) be the following:

- Add a mux type MAX (or LIMIT) to the existing mux types (REPLACE, MULTIPLY, ADD).

Does not seem very complicate, neither to code nor to understand. Anything I'm missing ?

MaX ( )

The problem is that you need a input-controlled limit.
The mixer defines functions which are of the form:
f1(x) <+/*> f2(y) <+/*> f3(z) ...
but you need one that is
f(x,y)
As I've shown above, it is complicated but can be achieved.

The complexity is in the guts of how the mixer works. you are right though, that one way to do this is to create new functions in addition to replace/add/mult, called 'min' and 'max', and that should work quite well.