Birko.Communication.Modbus

Modbus master protocol implementation for the Birko Framework, supporting both Modbus TCP (MBAP) and Modbus RTU (CRC-16) transports over any IPort.

Features

• Modbus TCP with MBAP header framing
• Modbus RTU with CRC-16 verification
• Read operations: Coils, Discrete Inputs, Holding Registers, Input Registers
• Write operations: Single/Multiple Coils, Single/Multiple Registers
• Response helpers: register extraction, Float32/Int32 decoding, coil unpacking
• Thread-safe client with configurable timeouts
• Works with any IPort transport (TCP, Serial, etc.)

Installation

This is a shared project (.projitems). Reference it from your main project:

<Import Project="..\Birko.Communication.Modbus\Birko.Communication.Modbus.projitems"
        Label="Shared" />

Dependencies

• Birko.Communication — Base IPort interface

Usage

Modbus TCP (Holding Registers)

using Birko.Communication.Modbus.Protocols;
using Birko.Communication.Network.Ports;

var port = new TcpIp(new TcpIpSettings { Address = "192.168.1.100", Port = 502 });

using var client = new ModbusClient(port, ModbusTransport.Tcp);
client.Connect();

// Read 10 holding registers starting at address 0
var response = client.ReadHoldingRegisters(unitId: 1, startAddress: 0, quantity: 10);
ushort[] values = response.GetRegisters();

// Read a 32-bit float from register pair
float temperature = response.GetFloat32(registerOffset: 0);

Modbus RTU (Serial)

using Birko.Communication.Modbus.Protocols;
using Birko.Communication.Hardware.Ports;

var port = new Serial(new SerialSettings
{
    Name = "COM1",
    BaudRate = 9600,
    Parity = Parity.None,
    DataBits = 8,
    StopBits = StopBits.One
});

using var client = new ModbusClient(port, ModbusTransport.Rtu);
client.Connect();

var response = client.ReadInputRegisters(unitId: 1, startAddress: 100, quantity: 2);
int powerValue = response.GetInt32(registerOffset: 0);

Write Operations

// Write single coil (ON)
client.WriteSingleCoil(unitId: 1, address: 0, value: true);

// Write single register
client.WriteSingleRegister(unitId: 1, address: 100, value: 0x1234);

// Write multiple registers
client.WriteMultipleRegisters(unitId: 1, startAddress: 100, values: new ushort[] { 0x0001, 0x0002, 0x0003 });

// Write multiple coils
client.WriteMultipleCoils(unitId: 1, startAddress: 0, values: new bool[] { true, false, true, true });

Reading Coils

var response = client.ReadCoils(unitId: 1, startAddress: 0, quantity: 16);
bool[] coilStates = response.GetCoils(16);

API Reference

Classes

Class	Description
ModbusClient	Thread-safe Modbus master client over any IPort
ModbusFrame	Static frame builder/parser for TCP (MBAP) and RTU (CRC-16)
ModbusResponse	Parsed response with register/coil/float/int helpers
ModbusException	Exception with standard Modbus error code mapping

Enums

Enum	Description
ModbusFunction	Function codes: ReadCoils (0x01) through WriteMultipleRegisters (0x10)
ModbusTransport	Transport mode: Tcp or Rtu

Namespace

• Birko.Communication.Modbus.Protocols

Related Projects

• Birko.Communication — Base communication abstractions (IPort)
• Birko.Communication.Network — TCP/UDP ports (Modbus TCP transport)
• Birko.Communication.Hardware — Serial ports (Modbus RTU transport)

License

Part of the Birko Framework.