w4k fails reading modbus rtu float32

[cgn]

Using a profile was my first try, but it didn't work. So I tried so solve it with this script. 

Code:

{
  "manufacturer": "Eastron",
  "description": "3-phasiger Energiezähler SDM72D-M",
  "mapping": [
    {
      "name": "Frequency",
      "address": 70,
      "type": "inputregister",
      "bus_datatype": "float32",
      "unit": "Hz"
    }
  ]
}

With this profile I get the value 16967.000. Which is wrong, it should be around 50. 

readinputregistervalue() - seems to be the problem. 

Code:

require('luamodbus')
mb = luamodbus.rtu()

mb:open('/dev/RS485', 9600, 'N', 8, 1, 'H')
mb:setslave(20)
mb:connect()



local r1 = mb:readregistervalue(70,"float16")
local r2 = mb:readregistervalue(71,"float16")


local value = mb:readregistervalue(70, "float32")
log(r1, r2, value)


mb:close()

log:

Code:

* arg: 1
  * number: 0
* arg: 2
  * number: 0
* arg: 3
  * number: 0