LUA - Swap Bytes

Question

I want to know if anyone could help me with this one.

I'm trying to read variables of a device (modbus) with a LUA scrip and it works. But I'm reading the variable swapped, I know I need to swap the bytes but how?

For exemple, my true value of the device is 1000 and my scrip is reading 59395.

Thanks guys.

This my code:

modbus_tcp = getfenv(0).modbus_tcp -- load the library

modbus_tcp.open(2,'10.50.80.10',502) -- Open the Modbus TCP connection

-- Read from ID 1, holding register 4101, two value: 
result,values=modbus_tcp.hr_read(2, 1799,10)

val1=values[1]
val2=values[2]
val3=values[3]
val4=values[4]
val5=values[5]
val6=values[6]
val7=values[7]
val8=values[8]
val9=values[9]


print(val1)
print(val2)
print(val3)
print(val4)
print(val5)
print(val6)
print(val7)
print(val8)
print(val9)
print(">------<")

modbus_tcp.close()  -- Close the Modbus TCP connection

Answer 1

You can use the following function:

function SwapValues(v)
     return (v-(math.modf(v/2^8)*2^8))*2^8+math.modf(59395/2^8)
end