A complete, idiomatic Elixir/OTP communication library for the DL/T 645-2007 (and 1997) electricity meter protocol.

Architecture & Key Features

• Pure Functional Codec (ExDlt645.Codec): Stateless packet encoding, decoding, +0x33 modulo 256 transformation, and checksum verification with binary pattern matching.
• Data Identifier Catalog (ExDlt645.DataId): Complete coverage of DL/T 645-2007 tables (A.1 Energy, A.2 Demand, A.3 Variables, A.4 Events, A.5 Parameters, A.6 Freeze, A.7 Load).
• BCD Number & Datetime Engine (ExDlt645.BCD): Fast little-endian BCD conversions for numeric readings, meter addresses, timestamps, and wildcard matching.
• Streaming Framer (ExDlt645.Framer): Circuits.UART.Framing behaviour implementation featuring preamble stripping, frame length deduction, and sliding-window byte-by-byte resynchronization.
• Pluggable Transport Layer (ExDlt645.Transport):
  • Hardware UART (ExDlt645.Transport.UART) powered by Circuits.UART.
  • In-Memory Virtual Bus (ExDlt645.Transport.Virtual & ExDlt645.VirtualBus) for hardware-free CI/CD and simulation.
  • Raw TCP Client (ExDlt645.Transport.Tcp) for Ethernet/4G DTU serial servers.
• Master Collector (ExDlt645.Master): Half-duplex serialized request execution, busy guard, active (asynchronous event streaming) and passive (synchronous call) modes.
• Slave Meter Simulator (ExDlt645.Slave): In-memory virtual meter grid component for automated testing and interactive protocol playgrounds.
• Telemetry (ExDlt645.Telemetry): Start/stop measurements with RTT for all requests.

Quick Start

1. In-Memory Virtual Loopback Testing (Hardware-free)

# Start a virtual electric meter slave
{:ok, _slave} = ExDlt645.Slave.start_link(address: "123456789012", tty: "virtual")

# Start a master collector on the same virtual bus
{:ok, master} = ExDlt645.Master.start_link(tty: "virtual")

# Read Total Forward Active Energy (DI: 0x00010000)
{:ok, energy} = ExDlt645.read_data(master, "123456789012", 0x00010000)
# => {:ok, 1234.56}

# Read Phase A Voltage (DI: 0x02010100)
{:ok, voltage} = ExDlt645.read_data(master, "123456789012", 0x02010100)
# => {:ok, 220.0}

# Broadcast read meter address
{:ok, addr} = ExDlt645.read_address(master)
# => {:ok, "123456789012"}

2. Physical RS-485 Serial Port

{:ok, master} = ExDlt645.Master.start_link(
  tty: "/dev/ttyUSB0",
  uart_opts: [speed: 2400, parity: :even]
)

{:ok, energy} = ExDlt645.read_data(master, "001234567890", 0x00010000)