How do you calculate the Check Sum on Incoming Hex Data to Stop bufferstring

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#1

HI All,

Any idea how to add the incoming data and they stop that buffer and wait for the next string of data? This is all hex data.

Thanks

#2

Hi Everyone,

I have the following code but I get an error can’t add chkincome, I am trying to add the incoming hex together to calculate the the string and end at the check sum. I am able to start because the hex string start is the same for everyone, the problem the hex string can be different lengths. I am figuring if i can add the hex and compare it to the incoming data when they match we have the check sum and end the statement.

local data = string.format(‘%02X’, string.byte(lul_data))
– Build incoming string
if (data == chkincome) then
bufferString = buffer … " " … data
luup.log("Print end bufferstring " … bufferString)
chkincome = “” – reset chkincome
elseif (data == HTD_cmd_start) then
buffer = data
bufferString = buffer
chkdata = “0x” … string.format( “%02x”, data )
else
buffer = buffer … " " … data
bufferString = buffer … " " … data
local chkincome = chkincome + chkdata
end

If you have an easy way that would be great.