node-red-contrib-deadband

Node-RED Deadband filter - only forwards values when the change exceeds a threshold.

Features

• Filters small value changes (noise)
• Configurable deadband threshold
• Optional initial reference value
• Runtime override via msg
• Reset function

Behavior

• Change >= Deadband → value is forwarded + new reference stored
• Change < Deadband → message is blocked, no output
• First value always passes through (sets reference)

Example

Deadband = 0.5, reference = 20.0:

Input 20.3 → Δ0.3 → blocked
Input 20.6 → Δ0.6 → forwarded, new ref = 20.6
Input 20.8 → Δ0.2 → blocked
Input 21.2 → Δ0.6 → forwarded, new ref = 21.2

Configuration

| Property | Description | Default | |----------|-------------|---------| | Deadband | Minimum change to forward value | 0.5 | | Initial Value | Initial reference value (optional) | - |

Input

msg.payload - Numeric value to filter

Runtime Overrides

| Property | Description | |----------|-------------| | msg.deadband | Overrides deadband temporarily | | msg.reset | true = reset reference value |

Output

{ "payload": 20.6 }

The original msg object is forwarded unchanged.

Use Cases

| Application | Deadband | |-------------|----------| | Temperature sensor | 0.5 | | Analog value (0-100) | 2 | | Power consumption (Watt) | 50 |

Node Status

• Idle - Waiting for first input
• ✓ 20.6 - Value forwarded
• ✗ 20.3 (Δ0.3) - Value blocked

Author

sr.rpo

License

MIT