node-red-contrib-netvar-utils

This module provides set of utility nodes in Node-RED for creating, parsing NVL (Network Variable List) UDP packets. Supports NVL of any size.

Created using @alexk111's node-red template

Nodes

nvl-json

Outputs JSON object with falsy values based on the configured NVL.

nvl-reader

Parses received NVL packets and returns the entire NVL as JSON object. Can be configured to emit message on each received packet or only when last expected packet is received. Currently nvl-reader will silently omit invalid packets.

nvl-emitter

Outputs NVL packet(s) using given JSON object. Input JSON object must have the same structure as the ones outputed via nvl-json and nvl-reader.

nvl-header

Outputs header details of NVL packet.

Example

JSON Structure

VAR_GLOBAL
  flag: BOOL;
  counter: WORD;
  message: STRING(50);
  wordArray: ARRAY [1..5] OF WORD;
  timeMatrix: ARRAY [1..2] OF ARRAY [1..3] OF WORD;
  threeD: ARRAY [0..1, 0..1, 0..1] OF WORD;
END_VAR 

will be converted to:

{
  "flag": false,
  "counter": 0,
  "message": "",
  "wordArray": [0,0,0,0,0],
  "timeMatrix": [
    [0,0,0],
    [0,0,0]
  ],
  "threeD": [
    [[0,0], [0,0]],
    [[0,0], [0,0]]
  ]
}

Supported Data Types

• ARRAY
• STRING
• BOOL
• BYTE, WORD, DWORD
• USINT, UINT, UDINT
• SINT, INT, DINT
• ULINT, LWORD, LINT
• TIME, TOD, TIME_OF_DAY
• DT, DATE_AND_TIME, DATE
• REAL, LREAL

TODO

• BigInt
• More detailed documentation for nodes
• Options to define how input is received and how output is delivered
• STRUCT
• Dynamic network variable lists
• Tests
• Usage Examples

License

MIT