knx-dpt-parser v1.0.0

knx-dpt-parser

Parser for KNX telegrams.

If you do not know what KNX is,
or do not know what group addresses are,
you are in the wrong repository

If you're still here...

Here is how to use it:

You have a node project that gets unparsed KNX telegram data. Header etc. need already to be interpreted, we deal with the payload only.
An example can be found in the testbusmonitor.js which is a simple group monitor which prints to stdout. There is a config variable on top to configure the connection to knxd

You require at least the Decorder.decode

var decode = require('knx-dpt-parser').decode;

Alternatively, you can use convenienceDecode() which adds some more easiness to DPT10 Time and DPT11 Date telegrams.

var decode = require('knx-dpt-parser').convenienceDecode;

Then in you code, if you have both, telegram payload and destination group address, you call the decoder

result  = decode(payload, dpttype);

The result is an object, containing one child object for each contained DPT-format (most types just have one format), plus an 'subitems' entry with the number of formats contained, and a 'TypeText' entry specifying the type of the DPT.
All format child objects contain a value field, containing the numeric value of the section (except for char/string types DPT4 & 16).

Example for a simple DPT1.001 telegram:

{'0': { value: 1, interpretation: 'True' }, TypeText: 'boolean', subitems: 1, value: 1 }

The last value field is available in the convenienceDecode() only.

A sample of a date DPT11.001, also by convenienceDecode() to get the combined value field:

 { '0': { value: null, interpretation: 'reserved' },
  '1': { value: 25, Unit: 'Day of month' },
  '2': { value: null, interpretation: 'reserved' },
  '3': { value: 2, Unit: 'Month' },
  '4': { value: null, interpretation: 'reserved' },
  '5': { value: 2017, Unit: 'Year' },
  TypeText: 'date',
  DPT: 'DPST-11-1',
  subitems: 6,
  value: '2017-02-25' 
 }

A sample of time DPT10.001

{ '0': { value: 6, interpretation: 'Saturday', Name: 'Day' },
  '1': { value: 17, Unit: 'hours', Name: 'Hour' },
  '2': { value: null, interpretation: 'reserved' },
  '3': { value: 55, Unit: 'minutes', Name: 'Minutes' },
  '4': { value: null, interpretation: 'reserved' },
  '5': { value: 40, Unit: 'seconds', Name: 'Seconds' },
  TypeText: 'time of day',
  DPT: 'DPST-10-1',
  subitems: 6,
  value: '17:55:40' 
}

The value generated by convenienceDecode() for Time types does not include the weekday.

Enumerative types (such as HVAC control mode DPT20.102) have the text of the mode in 'interpretation'.

{ '0': { value: 3, interpretation: 'Economy', Name: 'HVACMode' },
  TypeText: 'HVAC mode',
  DPT: 'DPST-20-102',
  subitems: 1 }

The dpttype parameter can either be a string like 'DPT1.001' or 'DPST-1-1', in fact '1.1' would be sufficient. It could optimize the process if you convert all DPTs to harmonised objects before using them regulary. For that, use dptobject = uniformDPT('string-1-1') and pass that object later to decode. You have to pay attention to the way you require the package, of course.