Negative values in hex, which expression?

[dontwarrior]

Hallo, first of all, congratulations for the great software you have created and participated, so far this is the most user friendly approach to control external synthesizers I’ve found, hats down.

I am building a panel for my EMU Proteus 2000, and so far it goes great, except that my programming (math) ability is quite limited and I need guidance to choose a correct expression to convert negative values in hex format.

The sysex string to control preset arpeggio speed looks like this (on page 62 from the specs – http://soundprogramming.net/manuals/E-Mu_ProteusFamily_Sysex2.2.pdf):

F0 18 0f 00 55 01 02 11 08 xx xx f7

where xx xx are 7 bits LSB and MSB (LS first)

The values are ranging from -2 to 2 and if I set those as the component minimal and maximum value it appears correct on the user interface, but I cannot figure out an expression to convert the value in negative numbers.
For this modulator there are just 5 difference settings and for this component I could do it with a workaround and input the string 5 times, but as I went trough the specs, there are many parameters that would require a expression function to convert to negative numbers as values range from negative to positive , e.g., preset LINK 1 level (-96 to +4):

F0 18 0f 00 55 01 02 02 0a xx xx f7

preset LINK 1 transpose (-24 to +24 )

F0 18 0f 00 55 01 02 04 0a xx xx f7

or LINK 1 pan (-64 to +64 )

F0 18 0f 00 55 01 02 03 0a xx xx f7

What is the best way to approach this? I went to the documentation, but my math understanding is someway limited regarding programing with expressions.

I will keep reading, but any help is appreciated

Thank you

[dontwarrior]

getting clear with this :), though it might take time to ring trough

Korg Z1 – Negative Values

[dontwarrior]

it worked with this formula in the expressions:

lt (modulatorValue, 0, 16383 – (abs(modulatorValue)), modulatorValue)

though in the first example of mine (the arpeggio speed) the -1 value is skiped (I can live with that), it works flawless with -96 +10 or -64 +64 ranges, by just configuring the min and max value of the component

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