Btw.: concerning the handing of negative values, I read somewhere in the forum about following solution which I’m also using in my panel.
In following example we want to range between -64..63, and send 0..127:
Component: set minimum value to -64, and maximum value to 63 -> this is the displayed value.
Modulator, first entries (I think that I don’t need to quote the descriptions): modulatorValue + 64, midiValue – 64
Advantage: the modulator receives/stores/sends exactly the same value which is used by the synth and transfered via SysEx, no special handling required in the Lua script.
Best Regards, Thorsten.