IEC 61326-2-5:2020

Overview

IEC 61326-2-5:2020 is a part of the IEC 61326 series that defines EMC requirements specifically for the field bus interfaces of field devices used in process control and process measuring. This part focuses only on the communication interface (not the device’s other functions) and provides test configurations, operational conditions and performance criteria for devices with fieldbus profiles defined in IEC 61784-1 (notably CP 1/1 and CP 3/2 in this edition).

Key points:

• Applies to field devices with interfaces according to IEC 61784-1:2019 (CP 1/1 and CP 3/2).
• Supplements general requirements in IEC 61326-1:2020.
• Defines EMC test plan elements, immunity and emission considerations, and reporting requirements.

Key Technical Topics and Requirements

• Scope limitation: Only the fieldbus interface is covered; other device functions follow other IEC 61326 parts.
• EMC test plan: Specifies EUT (equipment under test) configuration, operational states during testing, and required functional performance definitions.
• Immunity testing: Uses the conditions and test types in IEC 61326-1 while adding requirements specific to fieldbus interfaces (see Annexes AA and BB).
• Emission requirements: Clause 7 of IEC 61326-1 applies; fieldbus-related emissions must be considered in the overall emissions assessment.
• Performance criteria: Functional performance criteria are detailed; failures or degradations are assessed against pre-defined functions.
• Test reporting: Test reports must include specifics such as the type of shield connection at the EUT and information on the host system when relevant.
• Annexes:
  • Annex AA - test configurations and performance criteria for CP 1/1 interfaces.
  • Annex BB - test configurations and performance criteria for CP 3/2 interfaces.

Practical Applications and Users

Who uses this standard:

• Device manufacturers designing field devices with fieldbus interfaces (Fieldbus/Profibus/Profinet profiles per IEC 61784).
• EMC test laboratories performing immunity and emission testing on process instrumentation.
• System integrators and plant engineers who need to verify device interoperability under electromagnetic stress.
• Compliance engineers and certification bodies assessing conformity to EMC requirements for process control devices.

Practical actions:

• Use IEC 61326-2-5 together with IEC 61326-1:2020 to create a complete EMC test plan.
• Configure the EUT per Annex AA/BB depending on the protocol profile.
• Document host system details and shielding connections in reports to support conformity decisions.

Related Standards

• IEC 61326-1:2020 - General EMC requirements for measurement, control and laboratory equipment
• IEC 61784-1:2019 - Fieldbus profiles (protocol-specific profiles)
• IEC 61158 (relevant parts) - Fieldbus physical, data-link and application layer specifications

Keywords: IEC 61326-2-5:2020, EMC testing, field devices, field bus interfaces, IEC 61784-1, immunity testing, emissions, process control, test configurations.