A modern, performant, easy to use client and server implementation of Modbus, supporting:

Modbus TCP
Modbus TCP Security (Modbus TCP with TLS)
Modbus RTU on Serial
Modbus RTU on TCP

Quick Start Examples

Modbus TCP Client

var transport = NettyTcpClientTransport.create(cfg -> {
  cfg.setHostname("172.17.0.2");
  cfg.setPort(502);
});

var client = ModbusTcpClient.create(transport);
client.connect();

ReadHoldingRegistersResponse response = client.readHoldingRegisters(
    1,
    new ReadHoldingRegistersRequest(0, 10)
);

System.out.println("Response: " + response);

Modbus RTU on Serial Client

var transport = SerialPortClientTransport.create(cfg -> {
  cfg.setSerialPort("/dev/ttyUSB0");
  cfg.setBaudRate(115200);
  cfg.setDataBits(8);
  cfg.setParity(SerialPort.NO_PARITY);
  cfg.setStopBits(SerialPort.TWO_STOP_BITS);
});

var client = ModbusRtuClient.create(transport);
client.connect();

client.readHoldingRegisters(
    1,
    new ReadHoldingRegistersRequest(0, 10)
);

System.out.println("Response: " + response);

Maven

Modbus TCP

<dependency>
    <groupId>com.digitalpetri.modbus</groupId>
    <artifactId>modbus-tcp</artifactId>
    <version>2.1.4</version>
</dependency>

Modbus Serial

<dependency>
    <groupId>com.digitalpetri.modbus</groupId>
    <artifactId>modbus-serial</artifactId>
    <version>2.1.4</version>
</dependency>

Features

Supported Function Codes

Code | Function | Client | Server -------- | -------- | ------ | ------ 0x01 | Read Coils | ✅ | ✅ 0x02 | Read Discrete Inputs | ✅ | ✅ 0x03 | Read Holding Registers | ✅ | ✅ 0x04 | Read Input Registers | ✅ | ✅ 0x05 | Write Single Coil | ✅ | ✅ 0x06 | Write Single Register | ✅ | ✅ 0x0F | Write Multiple Coils | ✅ | ✅ 0x10 | Write Multiple Registers | ✅ | ✅ 0x16 | Mask Write Register | ✅ | ✅ 0x17 | Read/Write Multiple Registers | ✅ | ✅

raw/custom PDUs on Modbus/TCP
broadcast messages on Modbus/RTU
pluggable codec implementations
pluggable transport implementations

License

Eclipse Public License - v 2.0

Modbus

Install / Use

README