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)
• Modbus TCP
• Modbus RTU

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"] }

TCP client example

extern crate futures;
extern crate tokio_core;
extern crate tokio_modbus;

use tokio_core::reactor::Core;
use futures::future::Future;
use tokio_modbus::{Client, TcpClient};

pub fn main() {
    let mut core = Core::new().unwrap();
    let handle = core.handle();
    let addr = "192.168.0.222:502".parse().unwrap();

    let task = TcpClient::connect(&addr, &handle).and_then(|client| {
        println!("Fetching the coupler ID");
        client
            .read_input_registers(0x1000, 7)
            .and_then(move |buff| {
                println!("Response is '{:?}'", buff);
                Ok(())
            })
    });

    core.run(task).unwrap();
}

More examples can be found in the examples folder.

Protocol-Specification

• MODBUS Application Protocol Specification v1.1b3 (PDF)
• MODBUS over serial line specification and implementation guide v1.02 (PDF)
• MODBUS Messaging on TCP/IP Implementation Guide v1.0b (PDF)

Structs

RtuClient	Modbus RTU client
TcpClient	Modbus TCP client

Enums

Request	A request represents a message from the client (master) to the server (slave).
Response	The data of a successfull request.

Traits

Client

A transport independent client trait.