LM - integration with Mohlenhoff EZR system

Code:
grp.checkupdate = function(alias, newvalue, dpt, mindelta) 
  local curvalue, valdelta 

  -- get current object value 
  curvalue = grp.getvalue(alias) 

  -- value is numeric and delta is specified 
  if type(curvalue) == 'number' and type(mindelta) == 'number' then 
    newvalue = tonumber(newvalue) or 0 
    valdelta = math.abs(curvalue - newvalue) 

    -- delta is below minimum, do nothing 
    if valdelta < mindelta then 
      return 
    end 
  -- do not send same boolean values 
  elseif type(curvalue) == 'boolean' and curvalue == newvalue then 
    return 
  end 

  grp.update(alias, newvalue, dpt) 
end

http = require('socket.http')
url = 'http://192.168.1.111/data/dynamic.xml'

function starttag(p, tag, attr)
  local nr = tonumber(attr.nr)
  table.insert(path, tag)

  if nr then
    nrtag = tag
    table.insert(path, nr)
  end
end

function endtag(p, tag)
  table.remove(path)

  if tag == nrtag then
    nrtag = nil
    table.remove(path)
  end
end

function chardata(p, txt)
  local ptr, len

  txt = txt:trim()
  if #txt == 0 then
    return
  end

  ptr = result
  len = #path

  for i, tag in ipairs(path) do
    if i == len then
      ptr[ tag ] = txt
    elseif not ptr[ tag ] then
      ptr[ tag ] = {}
    end

    ptr = ptr[ tag ]
  end
end

-- current xml tree path
path = {}
-- resulting table
result = {}
-- tag name that contains "nr" attribute
nrtag = nil

lxp = require('lxp')
parser = lxp.new({
  StartElement = starttag,
  EndElement = endtag,
  CharacterData = chardata,
})

xml = http.request(url)
res = parser:parse(xml or '')

if res then

   log(result.Devices.Device.HEATAREA[ 1 ].HEATAREA_MODE)
   log(result.Devices.Device.HEATAREA[ 1 ].T_ACTUAL)
   log(result.Devices.Device.HEATAREA[ 1 ].T_TARGET)
   log(result.Devices.Device.HEATAREA[ 1 ].PROGRAM_WEEK)
   log(result.Devices.Device.HEATAREA[ 1 ].PROGRAM_WEEKEND)
   log(result.Devices.Device.HEATAREA[ 1 ].PARTY)
   log(result.Devices.Device.HEATAREA[ 1 ].PARTY_REMAININGTIME)
   log(result.Devices.Device.HEATAREA[ 1 ].ISLOCKED)
   log(result.Devices.Device.IODEVICE[ 1 ].SIGNALSTRENGTH)
   log(result.Devices.Device.IODEVICE[ 1 ].BATTERY)   
  
end

grp.checkupdate('2/1/1', result.Devices.Device.HEATAREA[ 1 ].HEATAREA_MODE, dt.uint8, 1)
grp.checkupdate('2/1/2', result.Devices.Device.HEATAREA[ 1 ].T_ACTUAL, dt.float16, 0.1)
grp.checkupdate('2/1/3', result.Devices.Device.HEATAREA[ 1 ].T_TARGET, dt.float16, 0.1)
grp.checkupdate('2/1/7', result.Devices.Device.HEATAREA[ 1 ].PROGRAM_WEEK, dt.float16, 1)
grp.checkupdate('2/1/8', result.Devices.Device.HEATAREA[ 1 ].PROGRAM_WEEKEND, dt.float16, 1)
grp.checkupdate('2/1/9', result.Devices.Device.HEATAREA[ 1 ].PARTY, dt.float16, 1)
grp.checkupdate('2/1/10', result.Devices.Device.HEATAREA[ 1 ].PARTY_REMAININGTIME, dt.float16, 1)
grp.checkupdate('2/1/12', result.Devices.Device.HEATAREA[ 1 ].ISLOCKED, dt.float16, 1)
grp.checkupdate('2/1/13', result.Devices.Device.IODEVICE[ 1 ].SIGNALSTRENGTH, dt.uint8, 1)
grp.checkupdate('2/1/14', result.Devices.Device.IODEVICE[ 1 ].BATTERY, dt.uint8, 1)