FlowMeasurement Cluster

Cluster ID: 0x0404  |  Endpoint: Typically on Endpoint 1+ (application endpoint)

FlowMeasurement measures the flow rate of liquids or gases. It is a read-only sensor Cluster — it has only 4 Attributes and no Commands. The device acts as a Server, passively reporting flow data, while the App (Client) simply reads or subscribes. Commonly found on water flow sensors, gas flow meters, and HVAC airflow detection devices.

Attribute Overview

FlowMeasurement has only four Attributes, of which MeasuredValue is the most commonly used. Click an Attribute ID to jump to its detailed description.

Attributes

MeasuredValue (Current Measured Flow Rate)

The most recently measured flow rate from the sensor, in units of 0.1 m³/h. This is the most important Attribute of the entire Cluster.

• Type: uint16 (unsigned)
• Range: 0 to 65534
• Nullable: null indicates the sensor data is invalid or the first measurement has not yet completed
• Conversion: Actual flow rate = MeasuredValue / 10 (unit: m³/h)

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MinMeasuredValue (Minimum Measurable Flow Rate)

The lowest flow rate the sensor can measure, in units of 0.1 m³/h. The App can use this to set the lower bound of the flow rate display range, or to determine whether the current reading has reached the minimum.

• Type: uint16, Nullable
• Range: 0 to MaxMeasuredValue - 1
• Nullable: null indicates the device has not defined a lower limit

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MaxMeasuredValue (Maximum Measurable Flow Rate)

The highest flow rate the sensor can measure, in units of 0.1 m³/h. When MeasuredValue approaches this upper limit, it may indicate the flow has exceeded the sensor's normal operating range.

• Type: uint16, Nullable
• Range: MinMeasuredValue + 1 to 65534
• Nullable: null indicates the device has not defined an upper limit

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Tolerance (Measurement Tolerance)

The measurement tolerance of the sensor, in units of 0.1 m³/h. For example, a value of 10 means a measurement accuracy of ±1.0 m³/h. This Attribute is optional and not all devices report it.

• Type: uint16 (unsigned, tolerance cannot be negative)
• Range: 0 to 2048 (i.e., 0 to ±204.8 m³/h)

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Commands

FlowMeasurement is a read-only Server Cluster with no Commands. The device is responsible for collecting flow data and updating Attributes; the App only needs to Read or Subscribe to obtain data.

Example Data

Reading the FlowMeasurement Cluster Attributes from a water flow sensor:

{
  // --- FlowMeasurement Cluster (Endpoint 1) ---
  "0x0": 150,        // MeasuredValue = 150 → actual 15.0 m³/h
  "0x1": 0,          // MinMeasuredValue = 0 → actual 0.0 m³/h
  "0x2": 5000,       // MaxMeasuredValue = 5000 → actual 500.0 m³/h
  "0x3": 10          // Tolerance = 10 → actual ±1.0 m³/h
}

Read request example — retrieve all Cluster Attributes at once:

{
  // Read all Attributes of the flow sensor
  "readRequests": [{
    "attributePath": {
      "endpointId": 1,
      "clusterId": "0x0404"
      // No attributeId specified → read all Attributes of this Cluster
    }
  }]
}

Subscribe to flow rate changes — track flow updates in real time:

{
  // Subscribe to flow rate changes (report every 10 seconds to 2 minutes)
  "subscribeRequests": [{
    "attributePath": {
      "endpointId": 1,
      "clusterId": "0x0404",
      "attributeId": "0x00"        // MeasuredValue
    },
    "minIntervalFloor": 10,        // Report at least every 10 seconds
    "maxIntervalCeiling": 120      // Report at most every 2 minutes
  }]
}

{`// Device returns MeasuredValue = 150
val rawValue: Int? = 150    // Nullable, may be null
val flowRate = rawValue?.let { it / 10.0 }  // → 15.0 m³/h
val flowLiterPerMin = flowRate?.let { it * 1000.0 / 60.0 }  // → 250.0 L/min

// Handle null when displaying
val display = flowRate?.let { String.format("%.1f m³/h", it) } ?: "--"`}

Common Scenarios