Rule for using only the lower byte of an 2 Byte value?

Setup, Configuration and Use Scripts & Rules
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2

given MB_I_Reg_10 as Number, you have to cast the state to byte (this would cut away the high byte)
Maybe this will do it (did not test it, as I’m at work)

rule "MB_I_Reg_10" 
when 
    Item MB_I_Reg_10 changed 
then
    SpitzbodenRT.sendCommand(MB_I_Reg_10.state as Byte) 
end

If this does not work as expected, type conversion should work:

SpitzbodenRT.sendCommand((MB_I_Reg_10.state as DecimalType).toBigDecimal.toBigInteger && 255)

I’m using .testBit(n) to get various boolean informations from a BigInt:

myState = (MyItem as DecimalType).toBigDecimal.toBigInteger
if(myState.testBit(0))
{}
if(myState.testBit(1))
{}
if(myState.testBit(2))
{}
if(myState.testBit(3))
{}
if(myState.testBit(4))
{}
...