About the Book

Document Scope

Use this document to:

Install and operate your M251 Logic Controller.
Connect the M251 Logic Controller to a programming device equipped with EcoStruxure Machine Expert software.
Interface the M251 Logic Controller with I/O expansion modules, HMI and other devices.
Familiarize yourself with the M251 Logic Controller features.

NOTE: Read and understand this document and all related documents before installing, operating, or maintaining your controller.

Validity Note

This document has been updated for the release of EcoStruxure™ Machine Expert V2.2.

For product compliance and environmental information (RoHS, REACH, PEP, EOLI, etc.), go to www.se.com/ww/en/work/support/green-premium/.

The characteristics of the products described in this document are intended to match the characteristics that are available on www.se.com. As part of our corporate strategy for constant improvement, we may revise the content over time to enhance clarity and accuracy. If you see a difference between the characteristics in this document and the characteristics on www.se.com, consider www.se.com to contain the latest information.

Available Languages of this Document

This document is available in these languages:

Related Documents

Title of Documentation	Reference Number
Modicon M251 Logic Controller - Programming Guide	EIO0000003089 (ENG) EIO0000003090 (FRE) EIO0000003091 (GER) EIO0000003092 (SPA) EIO0000003093 (ITA) EIO0000003094 (CHS)
EcoStruxure Machine Expert Industrial Ethernet Overview User Guide	EIO0000003053 (ENG) EIO0000003054 (FRE) EIO0000003055 (GER) EIO0000003056 (SPA) EIO0000003057 (ITA) EIO0000003058 (CHS)
Modicon TM3 Digital I/O Modules - Hardware Guide	EIO0000003125 (ENG) EIO0000003126 (FRE) EIO0000003127 (GER) EIO0000003128 (SPA) EIO0000003129 (ITA) EIO0000003130 (CHS) EIO0000003424 (POR) EIO0000003425 (TUR)
Modicon TM3 Expert I/O Modules - Hardware Guide	EIO0000003137 (ENG) EIO0000003138 (FRE) EIO0000003139 (GER) EIO0000003140 (SPA) EIO0000003141 (ITA) EIO0000003142 (CHS) EIO0000003428 (POR) EIO0000003429 (TUR)
Modicon TM3 Safety Modules - Hardware Guide	EIO0000003353 (ENG) EIO0000003354 (FRE) EIO0000003355 (GER) EIO0000003356 (SPA) EIO0000003357 (ITA) EIO0000003358 (CHS) EIO0000003359 (POR) EIO0000003360 (TUR)
Modicon TM3 Transmitter and Receiver Modules - Hardware Guide	EIO0000003143 (ENG) EIO0000003144 (FRE) EIO0000003145 (GER) EIO0000003146 (SPA) EIO0000003147 (ITA) EIO0000003148 (CHS) EIO0000003430 (POR) EIO0000003431 (TUR)
Modicon TM3 Bus Coupler - Hardware Guide	EIO0000003635 (ENG) EIO0000003636 (FRE) EIO0000003637 (GER) EIO0000003638 (SPA) EIO0000003639 (ITA) EIO0000003640 (CHS) EIO0000003641 (POR) EIO0000003642 (TUR)
Modicon TM4 Expansion Modules - Hardware Guide	EIO0000003155 (ENG) EIO0000003156 (FRE) EIO0000003157 (GER) EIO0000003158 (SPA) EIO0000003159 (ITA) EIO0000003160 (CHS)
Modicon TM5 Fieldbus Interface - Hardware Guide	EIO0000003715 (ENG) EIO0000003716 (FRE) EIO0000003717 (GER) EIO0000003718 (SPA) EIO0000003719 (ITA) EIO0000003720 (CHS)
M251 Logic Controller - Instruction Sheet	HRB59604

To find documents online, visit the Schneider Electric download center (www.se.com/ww/en/download/).

Product Related Information

DANGER
	HAZARD OF ELECTRIC SHOCK, EXPLOSION OR ARC FLASH Disconnect all power from all equipment including connected devices prior to removing any covers or doors, or installing or removing any accessories, hardware, cables, or wires except under the specific conditions specified in the appropriate hardware guide for this equipment. Always use a properly rated voltage sensing device to confirm the power is off where and when indicated. Replace and secure all covers, accessories, hardware, cables, and wires and confirm that a proper ground connection exists before applying power to the unit. Use only the specified voltage when operating this equipment and any associated products. Failure to follow these instructions will result in death or serious injury.

DANGER

HAZARD OF ELECTRIC SHOCK, EXPLOSION OR ARC FLASH

Disconnect all power from all equipment including connected devices prior to removing any covers or doors, or installing or removing any accessories, hardware, cables, or wires except under the specific conditions specified in the appropriate hardware guide for this equipment.
Always use a properly rated voltage sensing device to confirm the power is off where and when indicated.
Replace and secure all covers, accessories, hardware, cables, and wires and confirm that a proper ground connection exists before applying power to the unit.
Use only the specified voltage when operating this equipment and any associated products.

Failure to follow these instructions will result in death or serious injury.

DANGER
	POTENTIAL FOR EXPLOSION Only use this equipment in non-hazardous locations, or in locations that comply with Class I, Division 2, Groups A, B, C and D. Do not substitute components which would impair compliance to Class I, Division 2. Do not connect or disconnect equipment unless power has been removed or the location is known to be non-hazardous. Do not use the USB port(s), if so equipped, unless the location is known to be non-hazardous. Failure to follow these instructions will result in death or serious injury.

DANGER

POTENTIAL FOR EXPLOSION

Only use this equipment in non-hazardous locations, or in locations that comply with Class I, Division 2, Groups A, B, C and D.
Do not substitute components which would impair compliance to Class I, Division 2.
Do not connect or disconnect equipment unless power has been removed or the location is known to be non-hazardous.
Do not use the USB port(s), if so equipped, unless the location is known to be non-hazardous.

Failure to follow these instructions will result in death or serious injury.

WARNING
	LOSS OF CONTROL Perform a Failure Mode and Effects Analysis (FMEA), or equivalent risk analysis, of your application, and apply preventive and detective controls before implementation. Provide a fallback state for undesired control events or sequences. Provide separate or redundant control paths wherever required. Supply appropriate parameters, particularly for limits. Review the implications of transmission delays and take actions to mitigate them. Review the implications of communication link interruptions and take actions to mitigate them. Provide independent paths for control functions (for example, emergency stop, over-limit conditions, and error conditions) according to your risk assessment, and applicable codes and regulations. Apply local accident prevention and safety regulations and guidelines.¹ Test each implementation of a system for proper operation before placing it into service. Failure to follow these instructions can result in death, serious injury, or equipment damage.

WARNING

LOSS OF CONTROL

Perform a Failure Mode and Effects Analysis (FMEA), or equivalent risk analysis, of your application, and apply preventive and detective controls before implementation.
Provide a fallback state for undesired control events or sequences.
Provide separate or redundant control paths wherever required.
Supply appropriate parameters, particularly for limits.
Review the implications of transmission delays and take actions to mitigate them.
Review the implications of communication link interruptions and take actions to mitigate them.
Provide independent paths for control functions (for example, emergency stop, over-limit conditions, and error conditions) according to your risk assessment, and applicable codes and regulations.
Apply local accident prevention and safety regulations and guidelines.¹
Test each implementation of a system for proper operation before placing it into service.

Failure to follow these instructions can result in death, serious injury, or equipment damage.

¹ For additional information, refer to NEMA ICS 1.1 (latest edition), Safety Guidelines for the Application, Installation, and Maintenance of Solid State Control and to NEMA ICS 7.1 (latest edition), Safety Standards for Construction and Guide for Selection, Installation and Operation of Adjustable-Speed Drive Systems or their equivalent governing your particular location.

WARNING
	UNINTENDED EQUIPMENT OPERATION Only use software approved by Schneider Electric for use with this equipment. Update your application program every time you change the physical hardware configuration. Failure to follow these instructions can result in death, serious injury, or equipment damage.

Information on Non-Inclusive or Insensitive Terminology

As a responsible, inclusive company, Schneider Electric is constantly updating its communications and products that contain non-inclusive or insensitive terminology. However, despite these efforts, our content may still contain terms that are deemed inappropriate by some customers.

Terminology Derived from Standards

The technical terms, terminology, symbols and the corresponding descriptions in the information contained herein, or that appear in or on the products themselves, are generally derived from the terms or definitions of international standards.

In the area of functional safety systems, drives and general automation, this may include, but is not limited to, terms such as safety, safety function, safe state, fault, fault reset, malfunction, failure, error, error message, dangerous, etc.

Among others, these standards include:

Standard	Description
IEC 61131-2:2007	Programmable controllers, part 2: Equipment requirements and tests.
ISO 13849-1:2023	Safety of machinery: Safety related parts of control systems. General principles for design.
EN 61496-1:2020	Safety of machinery: Electro-sensitive protective equipment. Part 1: General requirements and tests.
ISO 12100:2010	Safety of machinery - General principles for design - Risk assessment and risk reduction
EN 60204-1:2006	Safety of machinery - Electrical equipment of machines - Part 1: General requirements
ISO 14119:2013	Safety of machinery - Interlocking devices associated with guards - Principles for design and selection
ISO 13850:2015	Safety of machinery - Emergency stop - Principles for design
IEC 62061:2021	Safety of machinery - Functional safety of safety-related electrical, electronic, and electronic programmable control systems
IEC 61508-1:2010	Functional safety of electrical/electronic/programmable electronic safety-related systems: General requirements.
IEC 61508-2:2010	Functional safety of electrical/electronic/programmable electronic safety-related systems: Requirements for electrical/electronic/programmable electronic safety-related systems.
IEC 61508-3:2010	Functional safety of electrical/electronic/programmable electronic safety-related systems: Software requirements.
IEC 61784-3:2021	Industrial communication networks - Profiles - Part 3: Functional safety fieldbuses - General rules and profile definitions.
2006/42/EC	Machinery Directive
2014/30/EU	Electromagnetic Compatibility Directive
2014/35/EU	Low Voltage Directive

In addition, terms used in the present document may tangentially be used as they are derived from other standards such as:

Standard	Description
IEC 60034 series	Rotating electrical machines
IEC 61800 series	Adjustable speed electrical power drive systems
IEC 61158 series	Digital data communications for measurement and control – Fieldbus for use in industrial control systems

Finally, the term zone of operation may be used in conjunction with the description of specific hazards, and is defined as it is for a hazard zone or danger zone in the Machinery Directive (2006/42/EC) and ISO 12100:2010.

NOTE: The aforementioned standards may or may not apply to the specific products cited in the present documentation. For more information concerning the individual standards applicable to the products described herein, see the characteristics tables for those product references.