Device Integrations

Flux communicates with physical devices using ModbusTCP protocol for real-time monitoring and control.

PowerPack BESS

Overview

PowerPack battery energy storage systems provide grid-scale energy storage with advanced control capabilities.

Specifications

• Capacity: 100-500 kWh
• Power: 50-250 kW
• Communication: ModbusTCP
• Response Time: <1 second

Modbus Registers

Register	Address	Type	Description
Target Power	2008	RW	Power setpoint (kW)
SOE	2026	RO	State of Energy (%)
Status	2000	RO	System status
Available Blocks	2028	RO	Inverter capacity
Command Source	2010	RW	Control mode ID

Control Sequence

// Read current state
soe := client.ReadRegister(2026)
status := client.ReadRegister(2000)

// Calculate and send command
if status == READY {
    target := calculateTarget(soe)
    client.WriteRegister(2008, target)
}

Acuvim II Meters

Overview

High-accuracy power meters for monitoring site electrical parameters.

Measurements

• Voltage (L-L, L-N)
• Current (per phase)
• Power (active, reactive, apparent)
• Energy (import/export)
• Power factor
• Frequency

Modbus Configuration

meter:
  type: acuvim2
  modbus:
    address: 1
    baud: 9600
    parity: none
    data_bits: 8
    stop_bits: 1

Register Map

Parameter	Start Address	Data Type	Scale
Voltage L1-N	0x0000	Float32	1
Current L1	0x0010	Float32	1
Power Total	0x0040	Float32	1000
Energy Import	0x0100	Float32	1

Communication Protocol

ModbusTCP Frame

Transaction ID: 2 bytes
Protocol ID: 2 bytes (0x0000)
Length: 2 bytes
Unit ID: 1 byte
Function Code: 1 byte
Data: Variable

Read Holding Registers (0x03)

// Read 10 registers starting at 2000
request := []byte{
    0x00, 0x01,  // Transaction ID
    0x00, 0x00,  // Protocol ID
    0x00, 0x06,  // Length
    0x01,        // Unit ID
    0x03,        // Function Code
    0x07, 0xD0,  // Start Address (2000)
    0x00, 0x0A,  // Quantity (10)
}

Write Single Register (0x06)

// Write value to register 2008
request := []byte{
    0x00, 0x01,  // Transaction ID
    0x00, 0x00,  // Protocol ID
    0x00, 0x06,  // Length
    0x01,        // Unit ID
    0x06,        // Function Code
    0x07, 0xD8,  // Register Address (2008)
    0x00, 0x64,  // Value (100)
}

Error Handling

Common Modbus Exceptions

Code	Name	Description
0x01	Illegal Function	Function code not supported
0x02	Illegal Address	Register address invalid
0x03	Illegal Value	Value outside valid range
0x04	Device Failure	Device unable to process

Retry Logic

func readWithRetry(addr uint16, retries int) (uint16, error) {
    for i := 0; i < retries; i++ {
        val, err := client.ReadRegister(addr)
        if err == nil {
            return val, nil
        }
        time.Sleep(time.Second * time.Duration(i+1))
    }
    return 0, fmt.Errorf("max retries exceeded")
}

Configuration Examples

BESS Configuration

devices:
  bess:
    - id: "uuid-here"
      name: "Site-BESS-01"
      type: "powerpack"
      modbus:
        host: "192.168.1.100"
        port: 502
        address: 1
        timeout: 5s
        retry_count: 3

Meter Configuration

devices:
  meters:
    - id: "uuid-here"
      name: "Grid-Meter"
      type: "acuvim2"
      modbus:
        host: "192.168.1.101"
        port: 502
        address: 2
        timeout: 5s

Testing Tools

modpoll

# Read BESS SOE
modpoll -m tcp -a 1 -r 2026 -c 1 192.168.1.100

# Write target power
modpoll -m tcp -a 1 -r 2008 -c 1 192.168.1.100 50

mbscan

# Scan for devices
mbscan -p 502 192.168.1.0/24

Next Steps

• Controller Architecture - How devices are managed
• Deployment Guide - Network setup
• API Reference - Device data access