node-red-contrib-difference 1.0.0

Node-RED difference calculator - calculates the difference between two numeric inputs

npm install node-red-contrib-difference

node-red-contrib-difference

Node-RED Difference Calculator - calculates the difference between two numeric input values.

Features

  • Calculates A - B from two input values
  • Configurable topic names for inputs
  • Absolute value mode (|A - B|)
  • Configurable decimal places (0-10)
  • Outputs detailed input info

Behavior

  • Input A identified by configurable topic (default: "a")
  • Input B identified by configurable topic (default: "b")
  • Result = A - B
  • Output triggered on every new message once both values are known

Example

topic="a", payload=24.5  → stored as A
topic="b", payload=18.2  → stored as B
Output: 24.5 - 18.2 = 6.3

Configuration

Property Description Default
Topic A Topic name for input A "a"
Topic B Topic name for input B "b"
Absolute Output absolute value false
Decimals Number of decimal places 2

Input

  • msg.payload - Numeric value
  • msg.topic - Required - Must match Topic A or Topic B

Runtime Override

Property Description
msg.reset true = reset both values

Output

{
  "payload": 6.3,
  "inputs": {
    "a": { "topic": "a", "value": 24.5 },
    "b": { "topic": "b", "value": 18.2 },
    "result": 6.3,
    "absolute": false
  }
}

Use Cases

Application Description
Temperature Difference between two sensors
Energy Consumption difference between readings
Level Water level difference

Node Status

  • a(24.5) - b(18.2) = 6.3 - Result calculated
  • Waiting for a... - Input A missing
  • Waiting for a and b... - Both inputs missing

Author

sr.rpo

License

MIT

Node Info

Version: 1.0.0
Updated 6 days ago
License: MIT
Rating: not yet rated

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Nodes

  • difference

Keywords

  • node-red
  • difference
  • subtract
  • minus
  • math
  • calculator

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