Modbus TCP connection datakom d-200 mk2

[admin]

The illegal data error seems to come from the device sending some extra byte when it should not. Unfortunately it's hard to tell why the connection stops working. Try this test script which discards any stale data before reading.

Code:

if not mb then
  require('luamodbus')
  mb = luamodbus.tcp()

  mb:setresponsetimeout(5)
  mb:open('10.36.0.25', 502)

  res, err = mb:connect()
  if res then
    
    buffer = {}
    mb:setdebug(function(msg)
      buffer[ #buffer + 1 ] = msg
    end)
  else
    log('modbus connect failed ' .. tostring(err))
    mb:close()
    mb = nil
  end
end

if mb then
  mb:flush()
  reg10240, reg10241, reg10242, reg10243, reg10244, reg10245, reg10246, reg10247 = mb:readregisters(10240, 8)
  
  if reg10240 then
    mains_l1_voltage = reg10240 / 10
    mains_l2_voltage = reg10242 / 10
    mains_l3_voltage = reg10244 / 10
    genset_l1_voltage = reg10246 / 10
    log('voltage values', mains_l1_voltage, mains_l2_voltage, mains_l3_voltage, genset_l1_voltage)
  else
    log('modbus read failed ' .. tostring(reg10241))
    mb:close()
    mb = nil
  end

  log(table.concat(buffer))
  buffer = {}
end