Crate rust_ethernet_ip 

EtherNet/IP client library for Allen-Bradley CompactLogix and ControlLogix PLCs.

rust-ethernet-ip provides async Rust APIs for explicit EtherNet/IP and CIP tag operations, plus FFI surfaces used by the repository’s .NET wrapper. The current released crate line is 1.2.0.

Highlights

• Async client API via EipClient
• Symbolic tag addressing, including program-scoped tags, array indexing, and nested UDT paths
• Batch reads, writes, and mixed execution with BatchOperation
• Route-path support for backplane and routed topologies via RoutePath
• UDT discovery, schema export, diagnostics, subscriptions, and tag-group polling

Quick Start

use rust_ethernet_ip::{EipClient, PlcValue};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let mut client = EipClient::connect("192.168.1.100:44818").await?;
    let running = client.read_tag("Program:Main.MotorRunning").await?;
    client
        .write_tag("Program:Main.SetPoint", PlcValue::Dint(1500))
        .await?;

    println!("running={running:?}");
    Ok(())
}

Routed example:

use rust_ethernet_ip::{EipClient, RoutePath};

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let route = RoutePath::new().add_slot(0);
    let _client = EipClient::with_route_path("192.168.1.100:44818", route).await?;
    Ok(())
}

Known PLC/Firmware Limits

Earlier release lines classified several direct write shapes as controller/firmware limitations. Hardware probes on 2026-07-02 through 2026-07-08 corrected that picture, and the fixes ship in this line. Real-hardware validation for the 1.2.0 release line (CompactLogix 5069-L330ERM fw38, full-coverage across Rust/C#/Python/C++) confirmed:

• Standalone standard Logix STRING tags write directly using the standard 0x02A0/0x0FCE structure encoding.
• Scalar UDT array element members (DINT/REAL/BOOL/INT) write directly when the full member path is preserved.
• STRING members inside UDTs and UDT array elements — including custom string types with a user-defined name/length (e.g. Str82, Str400) — write directly: the library discovers the target’s real structure handle instead of assuming the built-in 0x0FCE. A 0x2107 Read/Write Tag data-type mismatch here now indicates a genuine type mismatch, not a firmware block.
• Strings/structures larger than one CIP packet are read and written via CIP Read/Write Tag Fragmented (0x52/0x53).

Remaining limits: whole-UDT array-element writes as a single structure are not supported (update members individually), and read_tag returns custom string types as PlcValue::Udt — use read_string_tag when the tag is known to be a string. See docs/STRING_HANDLING.md for size limits per tag scope.

Re-exports

pub use batch::BatchConfig;

pub use batch::BatchError;

pub use batch::BatchOperation;

pub use batch::BatchResult;

pub use client::Backoff;

pub use client::Client;

pub use client::ConnectionEvent;

pub use client::EipClient;

pub use client::RetryClient;

pub use client::RetryPolicy;

pub use config::ProductionConfig;Deprecated

pub use config::ConnectionConfig;

pub use config::LogFormat;

pub use config::LogLevel;

pub use config::LogRotationSchedule;

pub use config::LoggingConfig;

pub use config::MonitoringConfig;

pub use config::PerformanceConfig;

pub use config::PlcSpecificConfig;

pub use config::SecurityConfig;

pub use error::EtherNetIpError;

pub use error::Result;

pub use fleet::Fleet;

pub use fleet::FleetEvent;

pub use monitoring::ProductionMonitor;Deprecated

pub use monitoring::ConnectionMetrics;

pub use monitoring::DiagnosticsSnapshot;

pub use monitoring::ErrorCategory;

pub use monitoring::ErrorMetrics;

pub use monitoring::HealthCheckMode;

pub use monitoring::HealthMetrics;

pub use monitoring::HealthStatus;

pub use monitoring::MonitoringMetrics;

pub use monitoring::OperationMetrics;

pub use monitoring::PerformanceMetrics;

pub use plc_manager::PlcManager;Deprecated

pub use plc_manager::PlcConfig;

pub use plc_manager::PlcConnection;

pub use route::RouteHop;

pub use route::RoutePath;

pub use schema::SchemaCapabilities;

pub use schema::SchemaDataType;

pub use schema::SchemaExport;

pub use schema::SchemaLibraryInfo;

pub use schema::SchemaRoutePath;

pub use schema::SchemaScope;

pub use schema::SchemaTag;

pub use schema::SchemaTargetInfo;

pub use schema::SchemaUdt;

pub use schema::SchemaUdtMember;

pub use subscription::SubscriptionManager;Deprecated

pub use subscription::SubscriptionManager as RealTimeSubscriptionManager;Deprecated

pub use subscription::SubscriptionOptions;

pub use subscription::SubscriptionOptions as RealTimeSubscriptionOptions;

pub use subscription::TagSubscription;

pub use subscription::TagSubscription as RealTimeSubscription;

pub use subscription::TagSubscriptionEvent;

pub use tag_group::TagGroupConfig;

pub use tag_group::TagGroupEvent;

pub use tag_group::TagGroupEventKind;

pub use tag_group::TagGroupFailureCategory;

pub use tag_group::TagGroupFailureDiagnostic;

pub use tag_group::TagGroupSnapshot;

pub use tag_group::TagGroupSubscription;

pub use tag_group::TagGroupValueResult;

pub use tag_manager::TagCache;Deprecated

pub use tag_manager::TagManager;

pub use tag_manager::TagMetadata;

pub use tag_manager::TagPermissions;

pub use tag_manager::TagScope;

Modules

batch

client

config

error

fleet

monitoring

plc_manager

route

schema

subscription

tag_group

tag_manager

tag_path

types

udt

version

Structs

TagAttributes

Tag attributes from PLC

UdtData

UdtDefinition

Definition of a User Defined Type

UdtMember

Member of a UDT

UdtTemplate

UDT Template information from PLC

Enums

PlcValue

TagPath

Represents different types of tag addressing supported by Allen-Bradley PLCs

Traits

EtherNetIpStream

Trait for streams that can be used with EipClient

Functions

init_tracing

Initialize tracing subscriber with environment-based filtering

try_init_tracing

Try to initialize tracing subscriber (non-panicking version)