RBgrid

Points

Overview

The Units Configuration page manages electrical measurement points in your RBgrid system. Units are logical abstractions representing different electrical components - from main supply connections to individual loads. Each unit combines a physical sensor with metadata, role definition, and statistical tracking to provide comprehensive energy monitoring.

Units Abstraction Concept

What are Units?

Units are measurement entities that represent specific electrical points in your system. Each unit:

  • Links to a physical sensor (current or voltage)
  • Has a defined role in the electrical system
  • Maintains its own statistics and history
  • Provides real-time measurements
  • Applies your tariff to compute cost (and the value of any exported energy) from the energy flow

Unit Categories

The system supports three categories of units:

  1. System Units (Special units with predefined roles)

    • Voltage Bus - Primary voltage reference
    • Main Supply - Grid connection point
    • Alternative Supply - a second (non-grid) supply input

  2. Load Units (Regular consumers)

    • Individual devices or zones
    • Configurable roles and statistics
    • Multiple units allowed

Special System Units

Voltage Bus Configuration

Purpose: Primary voltage measurement reference for the entire system

Key Characteristics:

  • Unique: Only ONE Voltage Bus per system
  • Required: Essential for power calculations
  • No Statistics: Real-time only, no historical storage
  • Cannot be deleted: like the main input, the Voltage bus point cannot be removed or unbound

Source: the voltage input (U, channel V) of an rbAmp module on the I²C bus. There is no user-selectable voltage sensor, GPIO pin or built-in ADC — the module measures and digitises voltage itself.

Configuration Parameters:

  • Name - Descriptive identifier (max 32 characters)
  • Location - Physical location (max 16 characters)

Functionality:

  • Provides the voltage reference for all power calculations
  • Real-time RMS voltage monitoring without historical storage

AC Grid - Main Supply

Purpose: Monitors the connection point to the external electrical grid

Key Characteristics:

  • Unique: Only ONE Main Supply allowed per system
  • Bidirectional: Supports both consumption and feed-in
  • Economic Tracking: Applies your tariff to compute import cost and the value of exported energy
  • Statistical Data: Maintains historical consumption and export data

Configuration Parameters:

  • Name - Descriptive identifier (max 32 characters)
  • Location - Physical location (max 16 characters)
  • Source Type - Read-only; set by the hub, not chosen here. A unit is bound to a specific sensor channel (see Sensor Selection) and the hub records that channel's source type. There is no user-selectable source and no built-in ADC — current and voltage are measured by the rbAmp I²C modules.
  • Sensor Selection - Current sensor from configured hardware
  • Statistics Period - Data aggregation period (see Statistics section)

Functionality:

  • Import Monitoring: Tracks energy consumed from grid
  • Export Monitoring: Tracks energy fed back to the grid
  • Cost Calculation: Applies tariffs to consumption
  • Export Value: Applies the feed-in rate to exported energy, per zone
  • Peak Demand: Records maximum power draw
  • Power Quality: Monitors power factor and harmonics

Actions:

  • EDIT MAIN SUPPLY - Modify configuration
  • NO MAIN SUPPLY - Remove special status (converts to regular unit)

Alternative Supply

Purpose: Monitors a second, non-grid supply input to the site

Key Characteristics:

  • Unique: Only ONE Alternative Supply allowed per system
  • Bidirectional: Tracks energy flowing in and out (import and export)
  • Economic Analysis: Computes import cost and export value per zone from the tariff plan

Configuration Parameters:

  • Name - Descriptive identifier (max 32 characters)
  • Location - Physical location (max 16 characters)
  • Source Type - Read-only; set by the hub, not chosen here. A unit is bound to a specific sensor channel (see Sensor Selection) and the hub records that channel's source type. There is no user-selectable source and no built-in ADC — current and voltage are measured by the rbAmp I²C modules.
  • Sensor Selection - Current sensor from configured hardware
  • Statistics Period - Data aggregation period

Functionality:

  • Flow Tracking: live and cumulative energy in and out on this input
  • Per-zone economics: import cost and export value from the tariff plan

Actions:

  • EDIT ALT SUPPLY - Modify configuration
  • NO ALT SUPPLY - Remove special status (converts to regular unit)

Regular Units (Loads)

Purpose: Monitor individual electrical consumers, zones, or circuits

Key Characteristics:

  • Multiple Units: Unlimited number of regular units
  • Flexible Roles: Can be configured for different purposes
  • Individual Statistics: Each unit maintains its own data
  • Grouping Support: Can be organized by location or type

Configuration Parameters:

  • Name - Device or circuit name (max 32 characters)
  • Location - Installation location (max 16 characters)
  • Type - CURRENT_LOAD, VOLTAGE_MONITOR, or POWER_METER
  • Role - Functional role in the system:
    • ZONE_LOAD - Area or room circuit
  • DEVICE_LOAD - Specific appliance
  • CRITICAL_LOAD - Essential equipment
  • HVAC_LOAD - Heating/cooling systems
  • LIGHTING_LOAD - Lighting circuits
  • Phase - Assigns which supply line this channel is measured against. It sets the reference voltage applied to the channel and how the channel's load is attributed to a line in per-line summaries. On a single-phase supply, all channels use the default 1P; a three-phase hub uses 3P. Single-phase and three-phase supplies are both supported; which supply systems are hardware-validated on your hub is reported by GET /api/v1/schema → enums.grid_system_validated.
  • Source Type - Read-only; set by the hub, not chosen here. A unit is bound to a specific sensor channel (see Sensor Selection) and the hub records that channel's source type. There is no user-selectable source and no built-in ADC — current and voltage are measured by the rbAmp I²C modules.
  • Sensor Selection - Any available sensor
  • Statistics Period - Data aggregation period

Actions per Unit:

  • EDIT - Modify unit configuration
  • DELETE - Remove unit from system
  • ADD UNIT - Create new measurement unit

Statistics Period Configuration

What is Statistics Period?

The Statistics Period defines how long historical data is stored and the granularity of data aggregation. It determines:

  • Memory allocation for historical data
  • Resolution of stored measurements
  • Available time ranges for analysis
  • Storage optimization strategy

Available Periods

Details on Tariffs seting page

Data Stored in Statistics

For each configured period, the system maintains:

Energy Metrics:

  • Total consumption (kWh)
  • Peak demand (kW)
  • Average power (W)
  • Minimum power (W)
  • Power factor (cosφ)

Economic Data:

  • Total cost (and export value)
  • Tariff periods applied
  • Peak vs off-peak consumption
  • Cost per kWh trends

Quality Metrics:

  • Voltage variations
  • Frequency deviations
  • THD (Total Harmonic Distortion)
  • Interruption events

Aggregated Values:

  • Hourly summaries
  • Daily profiles
  • Monthly totals
  • Yearly comparisons

Memory Management

Storage Allocation:

  • Each unit allocates memory based on selected period
  • Circular buffer implementation (oldest data overwritten)
  • Compression for long-term storage
  • Backup to external storage supported

Access Methods:

  • REST API endpoints for data retrieval
  • WebSocket streaming for real-time updates
  • CSV/JSON export functionality
  • MQTT publishing of summaries

Typical Configuration Examples

Example 1: Residential with a second supply

1. Voltage Bus: "Main Panel Voltage" (rbAmp module voltage input)
2. Main Supply: "Grid Connection" (100A CT, YEARLY statistics)
3. Alternative Supply: "Second Feed" (50A CT, YEARLY statistics)
4. Unit:
   - "Kitchen Circuit" (20A CT, WEEKLY)

Example 2: Small Business

1. Voltage Bus: "Distribution Board" (rbAmp module voltage input)
2. Main Supply: "Utility Meter" (100A CT, YEARLY statistics)
3. No Alternative Supply
4. Units:
   - "Office Zone" (50A CT, MONTHLY)
   - "HVAC System" (30A CT, WEEKLY)

Example 3: Alternative supply, no grid connection

1. Voltage Bus: "Panel Voltage" (rbAmp module voltage input)
2. No Main Supply
3. Alternative Supply: "Second Feed" (100A CT, YEARLY)
4. Units:
   - "Critical Loads" (20A CT, DAILY)
   - "Non-Critical" (30A CT, HOURLY)

Best Practices

Sensor Placement

  • Main Supply: At main breaker or utility meter
  • Alternative Supply: On the second supply's feed
  • Load Units: At distribution panel branches

Statistics Period Selection

  • Short periods (HOURLY/DAILY): For troubleshooting and optimization
  • Medium periods (WEEKLY/MONTHLY): For usage patterns and cost review
  • Long periods (QUARTERLY/YEARLY): For long-term trends

Naming Convention

  • Use descriptive names indicating function or location
  • Include power rating in name for easy identification
  • Group related units with consistent naming

Performance Impact

Processing Load

  • Each active unit adds 3-5% CPU usage
  • Statistics calculation occurs at period boundaries
  • Real-time data updates every 3 second

Troubleshooting

Unit Not Showing Data

  • Verify sensor is configured and enabled in Hardware Settings
  • Check sensor physical connection
  • Ensure unit source matches sensor configuration
  • Verify statistics period is set

Incorrect Measurements

  • Calibrate sensors on Calibration page
  • Check CT orientation (arrow toward load)
  • Verify correct sensor type selection
  • Ensure proper burden resistor for CT

Statistics Not Updating

  • Check the hub is flashed with the full v1.1 image, including the partition table
  • Verify sufficient free memory
  • Ensure system time is synchronized
  • Check statistics period configuration