IEC 61131-9-2022 PDF

Full title and description

Programmable controllers - Part 9: Single-drop digital communication interface for small sensors and actuators (SDCI). This part of IEC 61131 specifies a single-drop digital communication interface technology (commonly known as IO‑Link) that extends basic digital I/O to a point-to-point communication link for exchanging parameters, identification and diagnostics between simple sensors/actuators and controllers.

Abstract

IEC 61131-9:2022 defines the SDCI (IO‑Link) communication services and protocol for both SDCI Masters and Devices, covering the physical layer, data link layer and application layer (ISO/OSI model), and including EMC test requirements. The document is aimed at enabling reliable, low-cost digital communication for simple sensors and actuators in factory automation while excluding multi-drop topologies and integration specifics for higher‑level fieldbus systems.

General information

• Status: Published — International Standard (active edition/adopted as EN/ national adoptions available).
• Publication date: 30 May 2022 (IEC electronic publication date; EN/national adoption dates in 2022 vary by body).
• Publisher: International Electrotechnical Commission (IEC); published/adopted by national bodies as EN IEC (examples: BSI, AENOR).
• ICS / categories: 25.040.40 (Industrial process measurement and control); 35.240.50 (IT applications in industry).
• Edition / version: Edition 2.0 (2022).
• Number of pages: IEC electronic entry lists 677 pages; some EN/national PDF publications list ~336–339 pages for their published PDF editions (format/pagination varies by publisher/adoption).

Scope

This standard specifies SDCI (IO‑Link) technology for point-to-point communication between a single master and small sensors or actuators. It defines the protocol stack (physical, data link and application layers), service models, roles for Masters and Devices, and relevant EMC test requirements. It is intended primarily for use with simple, cost‑effective microcontroller‑based devices in factory automation. The standard does not address multi‑drop/multi‑point networks or how SDCI is integrated into particular higher‑level fieldbuses or systems.

Key topics and requirements

• Specification of SDCI communication services and protocol: physical layer, data link layer, application layer (ISO/OSI alignment).
• Definition of Master and Device roles, message types, parameter transfer, identification and diagnostic information exchange.
• Electrical/connector and timing characteristics appropriate for small sensors/actuators (point‑to‑point links, typical unshielded three‑wire cabling and M8/M12 port classes as used by IO‑Link implementations).
• EMC test requirements and conformance considerations for device interoperability.
• Scope exclusions: not intended for multi‑drop topologies or full integration rules for higher‑level fieldbuses (left to gateway/mapping specifications).

Typical use and users

Typical users include device manufacturers (sensors, actuators, IO‑Link masters), PLC and I/O module vendors, system integrators, machine builders and test laboratories. The technology is used in factory automation to enable parameterization, diagnostics and simple data exchange between controllers and low‑cost field devices.

Related standards

Related documents include other parts of the IEC 61131 series (e.g., IEC 61131‑1, IEC 61131‑2) and previous editions of Part 9 (2013). IO‑Link related specifications and ecosystem documents (IO‑Link consortium material) and later complementary standards such as IO‑Link Wireless / wireless extensions have also been standardized in related IEC work (wireless extensions published separately).

Keywords

IEC 61131‑9, SDCI, IO‑Link, single‑drop digital communication interface, programmable controllers, sensors, actuators, physical layer, data link layer, application layer, EMC, factory automation.

FAQ

Q: What is this standard?

A: It is Part 9 of the IEC 61131 family — "Programmable controllers — Single‑drop digital communication interface for small sensors and actuators (SDCI)" (commonly associated with IO‑Link). It formalizes the point‑to‑point communication technology for simple field devices.

Q: What does it cover?

A: It covers the SDCI protocol and services (physical, data link and application layers), device/master roles, parameter transfer, identification and diagnostics, and EMC test requirements; it does not cover multi‑drop networks or detailed integration into higher‑level fieldbuses.

Q: Who typically uses it?

A: Sensor and actuator manufacturers, IO‑Link master and PLC vendors, machine builders and system integrators, and test/conformance labs working in factory automation and industrial I/O.

Q: Is it current or superseded?

A: The 2022 edition is the current IEC edition published in 2022 (Edition 2.0). IEC lists a stability/planned review date in the mid‑2020s; national adoptions (EN IEC) were published in 2022. Users should check national publishers for the adopted PDF pagination and national status.

Q: Is it part of a series?

A: Yes — it is Part 9 of the IEC 61131 series (Programmable controllers). Other parts cover different aspects of programmable controllers (hardware, programming languages, tests and diagnostics, etc.).

Q: What are the key keywords?

A: SDCI, IO‑Link, single‑drop, programmable controllers, sensors, actuators, physical layer, data link, application layer, EMC, factory automation.