UL 61131-2
Standard for Programmable Controllers - Part 2: Equipment Requirements and Tests

Edition Number:2SCC Approved:--
Edition Date:2008-06-05DOD Approved: --
Price Code:FANSI Approved: 2017-03-24


    1.1 Scope and object

    This Part of IEC 61131 specifies requirements and related tests for programmable controllers (PLC) and their associated peripherals (for example, programming and debugging tools (PADTs), human-machine interfaces (HMIs), etc.) which have as their intended use the control and command of machines and industrial processes.

    PLCs and their associated peripherals are intended to be used in an industrial environment and may be provided as open or enclosed equipment. If a PLC or its associated peripherals are intended for use in other environments, then the specific requirements, standards and installation practices for those other environments must be additionally applied to the PLC and its associated peripherals.

    This standard also applies to any products performing the function of PLCs and/or their associated peripherals.

    Equipment covered in this standard is intended for use in overvoltage category II ( IEC 60664-1) in low-voltage installations, where the rated mains supply voltage does not exceed a.c. 1 000 V r.m.s. (50/60 Hz), or d.c. 1 500 V. (If PLCs or their associated peripherals are applied in overvoltage category III installations, then additional analysis will be required to determine the suitability of the equipment for those applications.)

    1.1DV Modification to Paragraph 4 of 1.1:

    Equipment operating at more than 600 V is considered as high voltage equipment with respect to the requirements in the National Electrical Code.

    This standard does not deal with the functional safety or other aspects of the overall automated system. PLCs, their application programme and their associated peripherals are considered as components of a control system.

    Since PLCs are component devices, safety considerations for the overall automated system including installation and application are beyond the scope of this standard. However, PLC safety as related to electric shock and fire hazards, electrical interference immunity and error detecting of the PLC-system operation (such as the use of parity checking, self-testing diagnostics, etc.), are addressed. Refer to IEC 60364 or applicable national/local regulations for electrical installation and guidelines.

    The object of this standard is

    – to establish the definitions and identify the principal characteristics relevant to the selection and application of PLCs and their associated peripherals;

    – to specify the minimum requirements for functional, electrical, mechanical, environmental and construction characteristics, service conditions, safety, EMC, user programming and tests applicable to PLCs and the associated peripherals.

    This Part also specifies

    a)    service, storage and transportation requirements for PLCs and their associated peripherals (Clause 4);

    b)    functional requirements for PLCs and their associated peripherals (Clause 5);

    c)    EMC requirements for PLCs and their associated peripherals (Clause 8);

    d)    safety requirements for PLCs and their associated peripherals (Clause 11);

    e)    information that the manufacturer is required to supply (Clauses 7, 10 and 14);

    f)    test methods and procedures that are to be used for the verification of compliance of PLCs and their associated peripherals with the requirements (Clauses 6, 9, and 12).

    The tests are type tests or production routine tests, and not tests related to the ways PLC systems are applied.

    1.101DV Addition of the following to 1.1:

    This equipment is intended for installation in accordance with the National Electrical Code (NEC) for use in ordinary locations. Requirements based on the NEC are found in Annex dva of this document.

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    • Cover
    • Transmittal
    • Table of Contents
    • UL Preface
    • Deviations
    • IEC Foreword
    • IEC Preface
    • IEC Introduction
      • PROGRAMMABLE CONTROLLERS – Part 2: Equipment requirements and tests
        • 1 General
          • 1.1 Scope and object
          • 1.2 Compliance with this standard
          • 1.3 Normative references
        • 2 Type tests
          • 2.1 Equipment to be tested (equipment under test/EUT)
          • 2.2 Special features for immunity and EMC tests
          • 2.3 Withstand test conditions
          • 2.4 Verification procedure
          • 2.5 Requirements for test programmes and proper functioning verification procedures (PFVPs) to be provided by the manufacturer
          • 2.6 General conditions for tests
        • 3 Terms and definitions
        • 4 Normal service conditions and requirements
          • 4.1 Climatic conditions and requirements
          • 4.2 Mechanical service conditions and requirements
          • 4.3 Transport and storage conditions and requirements
          • 4.4 Electrical service conditions and requirements
          • 4.5 Special conditions and requirements
        • 5 Functional requirements
          • 5.1 Functional power supply and memory back-up requirements
          • 5.2 Digital I/Os
          • 5.3 Analogue I/Os
          • 5.4 Communication interface requirements
          • 5.5 Main processing unit(s) and memory(ies) of the PLC-system requirements
          • 5.6 Remote input/output stations (RIOSs) requirements
          • 5.7 Peripherals (PADTs, TEs, HMIs) requirements
          • 5.8 PLC-system self-tests and diagnostics requirements
          • 5.9 Functional earthing
          • 5.10 Mounting requirements
          • 5.11 General marking requirements
          • 5.12 Requirements for normal service and functional type tests and verifications
          • 5.13 Requirements for information on normal service and function
        • 6 Normal service and functional type tests and verifications
          • 6.1 Climatic tests
          • 6.2 Mechanical tests
          • 6.3 Verification of special functional requirements for power ports and memory back-up – Special immunity limits for power ports
          • 6.4 Verification of input/output requirements
          • 6.5 Verification of communication interface requirements
          • 6.6 Verification of MPU requirements
          • 6.7 Verification of remote I/O stations
          • 6.8 Verification of peripheral (PADTs, TEs, HMIs) requirements
          • 6.9 Verification of PLC-system self-tests and diagnostics
          • 6.10 Verification of markings and manufacturer's documentation
        • 7 General information to be provided by the manufacturer
          • 7.1 Information on type and content of documentation
          • 7.2 Information on compliance with this standard
          • 7.3 Information on reliability
          • 7.4 Information on other conditions
          • 7.5 Information on shipping and storage
          • 7.6 Information on a.c. and d.c. power supply
          • 7.7 Information on digital inputs (current sinking)
          • 7.8 Information on digital outputs for alternating currents (current sourcing)
          • 7.9 Information on digital outputs for direct current (current sourcing)
          • 7.10 Information on analogue inputs
          • 7.11 Information on analogue outputs
          • 7.12 Information on communication interfaces
          • 7.13 Information on main processing unit(s) and memory(ies) of the PLC-system
          • 7.14 Information on remote input/output stations (RIOSs)
          • 7.15 Information on peripherals (PADTs, TEs, HMIs)
          • 7.16 Information on self-tests and diagnostics
        • 8 Electromagnetic compatibility (EMC) requirements
          • 8.1 General
          • 8.2 Emission requirements
          • 8.3 EMC immunity requirements
          • 8.4 Requirements for EMC tests and verifications
          • 8.5 Requirements for information on EMC
        • 9 Electromagnetic compatibility (EMC) type tests and verifications
          • 9.1 Electromagnetic compatibility-related tests
          • 9.2 Test environment
          • 9.3 Measurement of radiated interference
          • 9.4 Measurement of conducted interference
          • 9.5 Electrostatic discharge
          • 9.6 Radiofrequency electromagnetic field – Amplitude modulated
          • 9.7 Power-frequency magnetic fields
          • 9.8 Fast transient bursts
          • 9.9 High-energy surges
          • 9.10 Conducted radiofrequency interference
          • 9.11 Damped oscillatory wave (for zone C only)
          • 9.12 Voltage drops and interruptions – Power port type tests and verifications
        • 10 Electromagnetic compatibility (EMC) information to be provided by the manufacturer
        • 11 Safety requirements
          • 11.1 Protection against electrical shock
          • Internal wiring
          • 11.2 Protection against the spread of fire
          • 11.3 Limited power circuits
          • 11.4 Clearance and creepage distances requirements
          • 11.5 Flame-retardant requirements for non-metallic materials
          • 11.5.2DV.1 Insulating material
          • 11.5.2DV.2 Insulating barriers
          • 11.6 Temperature limits
          • 11.7 Enclosures
          • 11.8 Field-wiring terminals constructional requirements
          • 11.9 Provisions for protective earthing
          • 11.10 Wiring
          • 11.11 Switching devices
          • 11.12 Components
          • 11.13 Battery requirements
          • 11.14 Maximum voltage and minimum voltage
          • 11.15 Markings and identification
          • 11.16 Requirements for safety type tests and verifications
          • 11.17 Requirements for safety routine tests and verifications
          • 11.18 Requirements for information on safety
        • 12 Safety type tests and verifications
          • 12.1 Safety-related mechanical tests and verifications
          • 12.2 Safety-related electrical tests
          • 12.3 Single-fault condition test – General
          • 12.102DV.1 Printed Wiring Board Abnormal Operation Test
        • 13 Safety routine tests
          • 13.1 Dielectric withstand test
          • 13.2 Dielectric withstand verification test
          • 13.3 Protective earthing test
        • 14 Safety information to be provided by the manufacturer
          • 14.1 Information on evaluation of enclosures for open equipment (power dissipation)
          • 14.2 Information on mechanical terminal connection
    • Annex A(informative)Illustration of PLC-system hardware definitions
    • Annex B (informative) Digital input standard operating range equations
    • Annex C (normative)Test tools
    • Annex D (informative) Zone C – EMC immunity levels
    • Annex E (informative) Overvoltage example
    • Bibliography
    • Annex DVA (normative) Regulatory requirements based upon the National Electrical Code (NEC)
    • Annex DVB (informative) Component Reference Standards
    • Annex DVC (normative) IEC to USA Standard references
    • Annex DVD (normative) Secondary Circuits and Circuits Supplied by Battery
    • Annex DVE (normative) Enclosures for use with Industrial Control Equipment
    • Annex DVF(normative)Additional requirements for devices with integrally connected cables