Crate oms_modbus 

OMS Modbus — high-performance, transport-generic Modbus library in pure Rust.

Complete Master (client) and Slave (server) for TCP, RTU, and ASCII — all through a single unified API. Passive bus-level WireTap with microsecond timestamps, auto-reconnect with USB serial resilience, and spec-compliant RS-485 bus timing.

Quick start

use oms_modbus::*;
use std::net::{IpAddr, Ipv4Addr, SocketAddr};
use std::sync::Arc;
use std::time::Duration;

let addr = SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 0);
let server = tcp::TcpServer::bind(addr).await?;
let bind_addr = server.local_addr()?;
let store = Arc::new(SlaveStore::with_holding_registers(&[(0, 1234)]));
tokio::spawn(async move { server.serve_forever(store).await.ok(); });

let client = tcp::TcpClient::connect_with_timeout(
    bind_addr, Duration::from_secs(3),
).await?;
let regs = client.read_holding_registers(1, 0, 1).await?;

Key types

Type	Description
ModbusClient	Master (client) trait — TCP, RTU, ASCII share this API
SlaveStore	Default Slave (server) — in-memory register/coil store
Service	Trait for custom server backends
ClientOptions	Builder: timeout, capture, reconnect, bus timing
BusCapture	Recording + statistics — implements WireTap
WireTap	Passive bus observer — implement for custom capture
BusTiming	RS-485 frame spacing — per Modbus Serial Spec
ModbusError	Structured error — Display, detail(), label()

Examples

See the examples directory for 14 runnable examples covering TCP, RTU, ASCII, monitoring, reconnect, custom services, and bus timing.

Re-exports

pub use codec::calculate_crc;

pub use codec::calculate_lrc;

pub use reconnect::ReconnectConfig;

pub use bus_timing::BusTiming;

pub use capture::BusCapture;

pub use client::ModbusClient;

pub use error::ModbusError;

pub use frame::Exception;

pub use frame::ExceptionResponse;

pub use frame::FunctionCode;

pub use frame::Request;

pub use frame::Response;

pub use intercept::format_timestamp;

pub use intercept::PacketCapture;

pub use intercept::PacketData;

pub use intercept::PacketRecord;

pub use intercept::TrafficStats;

pub use options::ClientOptions;

pub use server::Service;

pub use server::HookedService;

pub use server::ServerHook;

pub use slave_store::SlaveStore;

pub use wire_tap::now_micros;

pub use wire_tap::WireTap;

Modules

ascii

bus_timing

Bus frame spacing — enforces minimum silence between Modbus frames.

capture

BusCapture — unified recording + statistics backend.

client

Modbus client (master) trait.

codec

Modbus codecs — RTU (CRC-16) and ASCII (LRC) framing.

error

Modbus error types and message constants.

frame

Modbus frame types — Request, Response, Exception, FunctionCode.

intercept

Packet data types for Modbus traffic capture.

monitor

Recording backends — in-memory, file, channel, and user-extensible.

options

Shared client options — capture, reconnect, timeout.

reconnect

Auto-reconnect configuration for all transports.

rtu

server

Modbus server (slave) service trait.

slave_store

In-memory Modbus slave register store.

tcp

transport

Transport implementations — TCP, RTU, ASCII clients and servers.

wire_tap

Passive bus observer — attached to the physical transport via SniffIo.