NewLife.Modbus - ModbusTcp/ModbusRTU

🌐 Languages: English | 简体中文 | 繁體中文 | Español | Português | Français | العربية | Русский | Deutsch | 日本語 | 한국어

Complete Modbus protocol implementation including ModbusTCP / ModbusRTU / ModbusASCII and multiple network variants, built on NewLife.IoT standard interfaces with IoTEdge gateway support.

Source: https://github.com/NewLifeX/NewLife.Modbus
Nuget: NewLife.Modbus / NewLife.ModbusRTU
Docs: 需求文档 / 架构设计 / 功能清单 / 竞品分析

Highlights

• Most Complete Protocol: Implements Modbus Application Protocol Specification V1.1b3 with all 19 function codes (12 public + 7 advanced), covering over 99% of common industrial operations; supports the Enron/Daniel floating-point extension for oil & gas registers
• Multiple Transport Variants: ModbusTCP (with optional TLS), ModbusUDP, ModbusRTU (serial), ModbusASCII (serial), ModbusRtuOverTCP, ModbusRtuOverUDP, ModbusRtuSimple — 7 variants in total
• Full Master & Slave: Complete implementations of both Master (client) and Slave (server), with Slave supporting concurrent multi-client connections
• Zero-Allocation Encoding: Hot paths use SpanReader / SpanWriter for zero-allocation encoding/decoding, reducing GC pressure
• Batch Optimization: BuildSegments automatically merges consecutive addresses, reading multiple points in a single request to reduce polling overhead
• IoT Driver Integration: Implements the IDriver standard interface for zero-code integration with IoTEdge platform, with 6 drivers to choose from
• Advanced Features: Auto-reconnect, async/await API, multi-slave network model, custom function code registration, broadcast mode
• Lightweight Serial: ModbusRtuSimple targets resource-constrained edge devices with fewer dependencies and smaller memory footprint
• APM Observability: Built-in ITracer tracing and ILog logging support, integrated with Stardust distributed platform
• Multi-Framework: net45 / net461 / netstandard2.0 / netstandard2.1 / net6.0 / net7.0 / net8.0 / net9.0 / net10.0

Supported Transport Variants

Variant	NuGet Package	Description
ModbusTCP	NewLife.Modbus	Standard Modbus TCP/IP with MBAP header + PDU, port 502
ModbusUDP	NewLife.Modbus	Modbus over UDP, connectionless transport
ModbusRtuOverTCP	NewLife.Modbus	RTU frames (with CRC) over TCP transport
ModbusRtuOverUDP	NewLife.Modbus	RTU frames (with CRC) over UDP transport
ModbusRTU	NewLife.ModbusRTU	Serial binary compact format, CRC-16 validation
ModbusASCII	NewLife.ModbusRTU	Serial ASCII hexadecimal format, LRC validation
ModbusRtuSimple	NewLife.ModbusRTU	Lightweight simplified serial implementation, direct SerialPort access, suitable for resource-constrained edge scenarios

Quick Start

Install NuGet Package

# TCP/UDP scenario (no serial port needed)
dotnet add package NewLife.Modbus

# Serial RTU/ASCII scenario
dotnet add package NewLife.ModbusRTU

Master - ModbusTCP Read/Write Registers

using NewLife;
using NewLife.IoT.Protocols;
using NewLife.Log;

// Create ModbusTCP connection
var modbus = new ModbusTcp
{
    Server = "192.168.1.100:502",
    Timeout = 3000,
    Log = XTrace.Log,       // Optional: enable communication log
};
modbus.Open();

// Read holding registers (FC03), station 1, starting address 0, read 10 registers
var registers = modbus.ReadRegister(host: 1, address: 0, count: 10);
Console.WriteLine($"Register values: {registers?.Join(", ")}");

// Read coils (FC01)
var coils = modbus.ReadCoil(host: 1, address: 0, count: 8);
Console.WriteLine($"Coil states: {coils?.Join(", ")}");

// Write single register (FC06)
modbus.WriteRegister(host: 1, address: 0, value: 1234);

// Write multiple registers (FC16)
modbus.WriteRegisters(host: 1, address: 0, values: [100, 200, 300]);

// Write single coil (FC05)
modbus.WriteCoil(host: 1, address: 0, value: 0xFF00);

Master - ModbusRTU Serial Communication

using NewLife.Log;
using NewLife.Serial.Protocols;

// Create ModbusRTU serial connection
var modbus = new ModbusRtu
{
    PortName = "COM3",       // Windows: "COM3", Linux: "/dev/ttyS0"
    Baudrate = 9600,
    Log = XTrace.Log,
};
modbus.Open();

// Read holding registers (FC03)
var registers = modbus.ReadRegister(host: 1, address: 0, count: 5);

// Write multiple registers (FC16)
modbus.WriteRegisters(host: 1, address: 0, values: [0xABCD, 0xEF01]);

Slave - TCP Simulation Server

using NewLife.IoT;
using NewLife.IoT.Models;
using NewLife.Log;

// Create and configure the slave
var slave = new ModbusSlave
{
    Port = 502,
    Log = XTrace.Log,
};

// Preset register data (holding registers, FC03/FC06 operations)
for (var i = 0; i < 100; i++)
    slave.Registers.Add(new RegisterUnit { Address = (UInt16)i, Value = (UInt16)(i * 10) });

// Preset coil data (FC01/FC05 operations)
for (var i = 0; i < 16; i++)
    slave.Coils.Add(new CoilUnit { Address = (UInt16)i, Value = (Byte)(i % 2) });

// Start the slave and begin listening
slave.Start();
Console.WriteLine("Modbus Slave started, port 502");

IoT Driver Layer Integration

using NewLife.IoT.Drivers;
using NewLife.IoT.ThingModels;

// Create TCP driver (supports IoTEdge driver standard interface)
var driver = new ModbusTcpDriver();
var parameter = new ModbusTcpParameter
{
    Server = "192.168.1.100:502",
    Host = 1,
    Timeout = 3000,
    BatchStep = 1,   // Points with address gap ≤1 are auto-merged into batch requests
    BatchSize = 100, // Maximum 100 points per batch
};

// Open driver (single connection reused)
var node = driver.Open(device: null, parameter);

// Batch read (automatically merges consecutive addresses to reduce request count)
IPoint[] points =
[
    new PointModel { Name = "Temperature", Address = "4x1", Type = "UInt16", Length = 2 },
    new PointModel { Name = "Running", Address = "1x1", Type = "Boolean", Length = 1 },
];
var result = driver.Read(node, points);

Ecosystem Map

NewLife is a layered ecosystem of independently versioned open-source projects. The map below is shared verbatim by every NewLife repository; each project links to its repository and its primary NuGet package.

Project	What it does	Downloads
Foundation
NewLife.Core	Logging, configuration, caching, networking, serialization, scheduling and APM tracing.
NewLife.XCode	Data middleware: single tables at the tens-of-billions scale, automatic sharding, read-write splitting, 10+ databases.
NewLife.Net	High-performance network library: 1.77M pps / 14.5 Gbps on a single machine (TCP 1KB, 2026-10), 4M long-lived TCP connections.
NewLife.Remoting	Protocol communication and RPC framework for client/server applications and IoT devices.
NewLife.Agent	Installs .NET applications as OS daemons: Windows services and Linux systemd.
NewLife.Templates	dotnet new project templates for console, web, API, service, data and IoT projects.
Data & Messaging
NewLife.Redis	Redis client with microsecond latency, millions of ops/s and built-in message queues.
NewLife.RocketMQ	Pure managed RocketMQ client for Apache RocketMQ and Alibaba Cloud Message Queue.
NewLife.MQTT	MQTT client and server, including Alibaba Cloud IoT connectivity.
NewLife.NovaDb	Hybrid database in C#: embedded or networked, relational, time-series, message queue and KV in one.
NewLife.MySql	MySql driver and helper layer built on the NewLife data stack.
Web, AI & Distributed
NewLife.Cube	Rapid admin-platform framework: permissions, SSO, OAuth server and CRUD scaffolding.
Stardust	Distributed service platform: node management, APM, configuration center, registry and release center.
AntJob	Distributed task and real-time data scheduling platform with sharding, retries and backfill.
NewLife.AI	Unified client for 46 LLM providers plus ChatAI, a ready-to-run web chat application.
Industrial & IoT
NewLife.IoT	IoT standard library defining protocol contracts and device abstractions.
NewLife.Modbus	Modbus TCP/RTU/ASCII implementation on top of NewLife.IoT.
NewLife.Siemens	Siemens PLC protocol on top of NewLife.IoT.
NewLife.Omron	Omron PLC protocol on top of NewLife.IoT.
NewLife.Melsec	Mitsubishi Melsec PLC protocol on top of NewLife.IoT.
NewLife.OPC	OPC client for industrial data access.	—
NewLife.BACnet	BACnet building-automation protocol stack.
ZeroIoT	Lightweight open-source IoT platform with gateway and device management.	—
Vehicle Telematics
NewLife.JT808	JT/T 808 vehicle positioning protocol: 70+ message bodies, 2011/2013/2019.
NewLife.JT809	JT/T 809 platform-to-platform protocol for transport authorities.
NewLife.JT1078	JT/T 1078 in-vehicle video: RTP parsing, FLV/fMP4 remuxing and live streaming.
Domain Components
NewLife.Office	One package for Excel, Word, PPT, PDF and 15+ document formats.
NewLife.Audio	Cross-platform audio: codecs, device I/O, DSP, containers and streaming.
NewLife.Video	Video codecs, container formats, frame processing and streaming.
NewLife.Map	Unified interface over Baidu, AMap, Tencent and Tianditu with geocoding and coordinate conversion.
NewLife.IP	IPv4 geolocation with an offline memory-mapped database and an online API fallback.
Tools & Products
CrazyCoder	Developer toolbox: network, serial port, crypto, regex, Modbus and MQTT.
GitCandy	Self-hosted Git source code management system.	—
LuckyClover	Installs the matching .NET runtime automatically when launched from an older host.	—

Badges show the primary package of each project; theme, extension and satellite packages are listed on their NuGet pages. The 30+ packages not listed here (FTP, LoRa, Office extensions, protocol drivers and more) are available under the NewLifeX organization and on newlifex.com.

Team

Founded in 2002, the NewLife team has spent more than two decades on the .NET and IoT ecosystem, maintains nearly 100 open-source projects (34 of them core to this map), and delivers integrated software and hardware solutions for power, logistics, healthcare, industrial control and internet industries. We live by the motto "learning has no seniority — mastery earns respect".

Open-source components have been downloaded 6.48M times from NuGet (ecosystem-wide, as of 2026-10).

Website: https://newlifex.com · Open source organization: https://github.com/NewLifeX

WeChat Official Account: 智能大石头 (scan to follow)