Looking at the chart for a sysex sending mastervolume to my SC-7, it seem mastervolume split on MSB and LSB why?
A volume is only 0-127?

So why both MSB and LSB, what is zero seems clear to me, but what is 127???
//Sysex start
//ID number Universal Realtime
//Device ID Broadcast
//Sub ID 1: Device control message
//Sub ID 2: mastervolums
//LSB
//MSB
//Sysex end

function masterVol(){
settingChange=[0xF0,0x7F,0x7F,0x04,0x01,0x00,0x00,0xF7];
settingChange[5]=document.getElementById("masterVolID").value;
settingChange[6]=document.getElementById("masterVolID").value;
outportarr[outportindex].send(settingChange);
}