[−][src]Crate tokio_modbus

A pure Rust Modbus library based on tokio.

Modbus is based on a master/slave model. To avoid confusions with the tokio terminology the master is called client and the slave is called server in this library.

Features

pure Rust library
async (non-blocking)
sync (blocking)
Modbus TCP
Modbus RTU
Client & Server
Open Source (MIT/Apache-2.0)

Installation

Add this to your Cargo.toml:

[dependencies]
tokio-modbus = "*"

If you like to use Modbus TCP only:

[dependencies]
tokio-modbus = { version = "*", default-features = false, features = ["tcp"] }

If you like to use Modbus RTU only:

[dependencies]
tokio-modbus = { version = "*", default-features = false, features = ["rtu"] }

If you like to build a TCP server:

[dependencies]
tokio-modbus = { version = "*", default-features = false, features = ["tcp", "server"] }

Examples

TCP client

#[cfg(feature = "tcp")]
#[tokio::main]
pub async fn main() -> Result<(), Box<dyn std::error::Error>> {
    use std::future::Future;
    use tokio::runtime::Runtime;
    use tokio_modbus::prelude::*;

    let socket_addr = "192.168.0.222:502".parse().unwrap();

    let mut ctx = tcp::connect(socket_addr).await?;
    let data = ctx.read_input_registers(0x1000, 7).await?;
    println!("Response is '{:?}'", data);

    Ok(())
}

Sync TCP client

#[cfg(all(feature = "tcp", feature = "sync"))]
pub fn main() -> Result<(), Box<dyn std::error::Error>> {
    use tokio_modbus::prelude::*;

    let socket_addr = "192.168.0.222:502".parse()?;
    let mut client = client::sync::tcp::connect(socket_addr)?;
    let data = client.read_input_registers(0x1000, 7)?;
    println!("Response is '{:?}'", data);

    Ok(())
}

RTU client

#[cfg(feature = "rtu")]
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    use std::future::Future;
    use tokio::runtime::Runtime;
    use tokio_serial::{Serial, SerialPortSettings};

    use tokio_modbus::prelude::*;

    let tty_path = "/dev/ttyUSB0";
    let slave = Slave(0x17);

    let mut settings = SerialPortSettings::default();
    settings.baud_rate = 19200;
    let port = Serial::from_path(tty_path, &settings).unwrap();

    let mut ctx = rtu::connect_slave(port, slave).await?;
    println!("Reading a sensor value");
    let rsp = ctx.read_holding_registers(0x082B, 2).await?;
    println!("Sensor value is: {:?}", rsp);

    Ok(())
}

More examples can be found in the examples folder.

Protocol-Specification

Modules

client
prelude
slave