Norwegian HAN-interface - Kamstrup meter

[oveh]

Thanks for improvement suggestion, Admin. I didn't know that successive concatenations to a single string have poor performance.  I am new to LUA, so i appreciate feedback, how to optimize the code.

Tokatubs.
Working away from home at the moment, and will not be able to test before end of February.
However, i did bring some samples of the data packages sent from the meter with me, and have been playing a little bit with them on my Laptop.

My first plan was to iterate through the whole package, and parse all the obis data and values. But since the packages always have the data i need in the same position every time, i decided that verifying the data package, and read out the data from the known position, would be both easier for me and less demanding for the LM.  

Here is the code i have so far, works fine in ZeroBrane Studio:

Code:

------------------------------------------------------------------------------------
-- Sample data from 3 phase Kamstrup power meter
-- Type: 6841121BN243101040
-- Tested on ZeroBrane Studio, with Lua Interpreter: Lua (LuaJit)
------------------------------------------------------------------------------------


-- LuaJIT BitOp, same as LM bit lib?
local bit = require("bit")

-- 10 sec sample telegrams
sample_1 = string.char( 0x7e, 0xa0, 0xe2, 0x2b, 0x21, 0x13, 0x23, 0x9a, 0xe6, 0xe7, 0x00, 0x0f, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x07, 0xe3, 0x01, 0x15, 0x01, 0x17, 0x2b, 0x0a, 0xff, 0x80, 0x00, 0x00, 0x02, 0x19, 0x0a, 0x0e, 0x4b, 0x61, 0x6d, 0x73, 0x74, 0x72, 0x75, 0x70, 0x5f, 0x56, 0x30, 0x30, 0x30, 0x31, 0x09, 0x06, 0x01, 0x01, 0x00, 0x00, 0x05, 0xff, 0x0a, 0x10, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x09, 0x06, 0x01, 0x01, 0x60, 0x01, 0x01, 0xff, 0x0a, 0x12, 0x36, 0x38, 0x34, 0x31, 0x31, 0x32, 0x31, 0x42, 0x4e, 0x32, 0x34, 0x33, 0x31, 0x30, 0x31, 0x30, 0x34, 0x30, 0x09, 0x06, 0x01, 0x01, 0x01, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x0b, 0x08, 0x09, 0x06, 0x01, 0x01, 0x02, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x00, 0x00, 0x09, 0x06, 0x01, 0x01, 0x03, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x01, 0xd1, 0x09, 0x06, 0x01, 0x01, 0x04, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x00, 0x00, 0x09, 0x06, 0x01, 0x01, 0x1f, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x04, 0x43, 0x09, 0x06, 0x01, 0x01, 0x33, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x02, 0xee, 0x09, 0x06, 0x01, 0x01, 0x47, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x02, 0x2d, 0x09, 0x06, 0x01, 0x01, 0x20, 0x07, 0x00, 0xff, 0x12, 0x00, 0xdc, 0x09, 0x06, 0x01, 0x01, 0x34, 0x07, 0x00, 0xff, 0x12, 0x00, 0xdd, 0x09, 0x06, 0x01, 0x01, 0x48, 0x07, 0x00, 0xff, 0x12, 0x00, 0xdf, 0x6b, 0xaa, 0x7e )

sample_2 = string.char( 0x7e, 0xa0, 0xe2, 0x2b, 0x21, 0x13, 0x23, 0x9a, 0xe6, 0xe7, 0x00, 0x0f, 0x00, 0x00, 0x00, 0x00, 0x0c, 0x07, 0xe3, 0x01, 0x1d, 0x02, 0x09, 0x39, 0x1e, 0xff, 0x80, 0x00, 0x00, 0x02, 0x19, 0x0a, 0x0e, 0x4b, 0x61, 0x6d, 0x73, 0x74, 0x72, 0x75, 0x70, 0x5f, 0x56, 0x30, 0x30, 0x30, 0x31, 0x09, 0x06, 0x01, 0x01, 0x00, 0x00, 0x05, 0xff, 0x0a, 0x10, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x31, 0x09, 0x06, 0x01, 0x01, 0x60, 0x01, 0x01, 0xff, 0x0a, 0x12, 0x36, 0x38, 0x34, 0x31, 0x31, 0x32, 0x31, 0x42, 0x4e, 0x32, 0x34, 0x33, 0x31, 0x30, 0x31, 0x30, 0x34, 0x30, 0x09, 0x06, 0x01, 0x01, 0x01, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x15, 0x30, 0x09, 0x06, 0x01, 0x01, 0x02, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x00, 0x00, 0x09, 0x06, 0x01, 0x01, 0x03, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x01, 0x38, 0x09, 0x06, 0x01, 0x01, 0x04, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x00, 0x00, 0x09, 0x06, 0x01, 0x01, 0x1f, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x08, 0xab, 0x09, 0x06, 0x01, 0x01, 0x33, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x07, 0xb2, 0x09, 0x06, 0x01, 0x01, 0x47, 0x07, 0x00, 0xff, 0x06, 0x00, 0x00, 0x02, 0x37, 0x09, 0x06, 0x01, 0x01, 0x20, 0x07, 0x00, 0xff, 0x12, 0x00, 0xd6, 0x09, 0x06, 0x01, 0x01, 0x34, 0x07, 0x00, 0xff, 0x12, 0x00, 0xda, 0x09, 0x06, 0x01, 0x01, 0x48, 0x07, 0x00, 0xff, 0x12, 0x00, 0xdd, 0x21, 0x57, 0x7e )

-- Table dump / pretty print function found online:
-- http://lua-users.org/wiki/TableSerialization
function print_r (t, indent) -- alt version, abuse to http://richard.warburton.it
 local indent=indent or ''
 for key,value in pairs(t) do
   io.write(indent,'[',tostring(key),']')
   if type(value)=="table" then io.write(':\n') print_r(value,indent..'\t')
   else io.write(' = ',tostring(value),'\n') end
 end
end


--  Return CRC-16/X-25
function crc16(data)
 local crc = 0xFFFF
for i = 1, #data do
   crc = bit.bxor(crc, data:byte(i))
   for j = 1, 8 do
     local k = bit.band(crc, 1)
     crc = bit.rshift(crc, 1)
     if k ~= 0 then
       crc = bit.bxor(crc, 0x8408)
       end
     end
   end
   return bit.bxor(crc, 0xFFFF)
end


-- Convert 2 bytes to number
function uint16(b)
 if( #b ~= 2) then
   return
 else
   return bit.lshift(b:byte(1),8) + b:byte(2)
 end
end


-- Convert 4 bytes to number
 function uint32(b)
   if( #b ~= 4) then
     return
   else
   --Workaround needed...  lshift(XX,24) gives som strange results on numbers bigger than 0x7f....
   --return bit.lshift(b:byte(1),24) + bit.lshift(b:byte(2),16) + bit.lshift(b:byte(3),8) + b:byte(4)
     return b:byte(1) * 2 ^ 24       + bit.lshift(b:byte(2),16) + bit.lshift(b:byte(3),8) + b:byte(4)
   end
 end  


-- Convert 12 byte octet-string to date/time
function date_time(b)
 if (#b ~= 12) then
   return
 end
 local weekdays = {"Mon","Tue","Wed","Thu","Fri","Sat","Sun"}
 local t = {}
 t.year = uint16(b:sub(1,2))
 t.month = b:byte(3)
 t.day = b:byte(4)
 t.wday = weekdays[b:byte(5)]
 t.hour = b:byte(6)
 t.min = b:byte(7)
 t.sec = b:byte(8)
 return  t
end



function parse(b)
 
  -- Check package length
 if (#b ~= 228) then
   print("Error: Wrong package length, 10 sec package should be 228 bytes")
   return
 end

-- Check start and stop flag
 if ( b:byte(1) ~= 0x7E or b:byte(-1) ~= 0x7E) then
   print("Error: Wrong start and/or stop flag, both must be 0x7E on valid package")
   return
 end
 
 -- Parse checksum bytes -> 0xAA, 0xBB -> 0xBBAA
 check_sum= bit.lshift(b:byte(-2),8) + b:byte(-3)
 
 -- Compare checksum bytes with calculated cheksum
 if ( check_sum ~= crc16( b:sub(2,-4))) then
   print("Error: CRC mismatch")
   return
 end
 
 -- Verify list version
 if ( b:sub(34,47) ~= "Kamstrup_V0001") then
   print("Error: Not Kamstrup_V0001 list")
   return
 end
 
 -- All looks good so far. Read out data from package
 local t = {}
 t.time    = date_time(b:sub(18,29))
 t.version = "Kamstrup_V0001"
 t.id      = b:sub(58,73)
 t.type    = b:sub(84,101)
 -- P: Active power in Watt
 -- Q: Reactive power in kVar
 -- I: Current in Amp
 -- U: Voltage in Volt
 t.P       = { imp = uint32(b:sub(111,114)), exp = uint32(b:sub(124,127)) }
 t.Q       = { imp = uint32(b:sub(137,140)), exp = uint32(b:sub(150,153)) }
 t.I       = { uint32(b:sub(163,166)) / 100, uint32(b:sub(176,179)) / 100, uint32(b:sub(189,192)) / 100 }
 t.U       = { uint16(b:sub(202,203))      , uint16(b:sub(213,214))      , uint16(b:sub(224,225)) }
 
 return t
end


result = parse(sample_1)
--result = parse(sample_2)


if (result) then
 
 print_r(result)
 
 --update_influxDB(result)
 --update_kamstrup_grp(result)
 
end

Some more info how to parse the data:

Code:

Datatypes:

structure        02 LL            (LL elements)
octet-string     09 LL   XX ..       (LL bytes)
visible-string   0A LL   XX ..       (LL bytes)
unsigned32       06      XX XX XX XX    (04 bytes)
unsigned16       12      XX XX        (02 bytes)



OBIS CODE - octet-string[06]
09 06    01 01 1F 07 00 FF  =  1.1.31.07.00.255



Date/time - octet-string[0C]
09 0C    07 E3 01 1D 02 0B 00 05 FF 80 00 00
          2019/01/29 Tu 11:00:05

Byte[1-2]    Year
Byte[3]      Month
Byte[4]      Day of month

Byte[5]      Day of week, 1= Mon, 7 = Sun
Byte[6]      Hours
Byte[7]      Min
Byte[8]      Sec

Byte[9-0C]   ....

This date/time format is also used in the header,
but without the octet-string identifier 0x09