EMC for Functional Safety: Agriculture/Forestry, Construction, and Tractors Cover a Lot of Ground
March 29th, 2023
Electromagnetic compatibility (EMC) testing of construction, tractors, and agricultural (Ag)/forestry equipment is an important phase in the design and manufacture of these large and complex systems. In this article, we review the functional safety aspects of their EMC evaluation including the applicable regulations and compliance standards.
Directives and Regulations
In the European Union (EU), the EMC Directive 2014/30/EU sets the essential requirements for electromagnetic emissions along with a quality-related performance level for machine-function EMC immunity and for immunity of electronic subassemblies. In addition, the Machinery Directive 2006/42/EC establishes safety requirements to prevent injury to operators, people nearby, as well as to prevent property damage. EMC is one of many aspects of machine safety that is evaluated during the Machinery Directive conformity assessment process.
With Brexit changes for England, Scotland, and Wales, a parallel set of EMC regulations are also in place for the United Kingdom (UK). Presently the technical EMC regulatory requirements for the EU and UK are identical.
While EMC is a government specified requirement in Europe and for many countries outside of North America, in the USA and Canada EMC immunity testing is not a government defined requirement. Regardless, EMC immunity and emissions are an important concern for equipment manufacturers for domestic markets and abroad. To ensure their products operate safely and reliably, OEMs develop corporate EMC design and test standards that typically meet or exceed the European regulatory requirements in all equipment applications for the markets they serve.
To demonstrate compliance with the European Directives and regulations, manufacturers can test to harmonized Euro-Norm (EN) standards that are published in the Official Journal of the European Union (OJEU). The current version(s) of these harmonized standards can be accessed at the European Union EUROPA.eu and the UK.gov websites.
The compliance standards for European EMC testing on machinery are noted in the following table.
Some of these standards are applicable to the EMC Directive for emissions and quality-related immunity. Others cover EMC immunity testing for functional safety evaluations in the Machinery Directive, and some are specific to EMC testing for Ag and Forestry Tractor approvals. A highlight summary of each follows below.
EN ISO 14982:2009 Ag & Forestry Machinery
This is the current harmonized standard for Ag and forestry machinery and is also referenced for the compliance evaluation of tractors. It is published in the OJEU for both the EMC Directive and the Machinery Directive. Since it is a harmonized standard for the Machinery Directive, testing to this 2009 version in-full offers the presumption of conformity for safety related machine functions.
ISO DIS 14982-1:2021 Ag & Forestry Machinery
This is a new draft standard for the EMC Directive, but it is not yet published in the OJEU. Compared to the 2009 version, this standard is a more robust requirement that widens the test frequency ranges, updates test methods, and adds new pulse modulations. The advantage is that testing per the 2021 version meets and exceeds 14982:2009 and provides continuity in compliance when it will eventually replace the 2009 edition. This is an EMC Directive only standard that sets the emissions requirements. It also includes immunity testing for machine operations and ESAs that do not have a safety related function.
ISO DIS 14982-2:2021 Ag & Forestry Machinery
This is a new draft Machinery Directive standard which covers EMC immunity testing only. It specifies additional requirements under the aspect of functional safety for machinery and ESAs. Since it is not yet published in the Machinery Directive OJEU its application is voluntary. The benefit of testing to this standard is that it meets and exceeds the 14982:2009 immunity requirements and provides continuity in compliance when it will eventually replace the 2009 edition.
It introduces the concept of applying machinery risk assessments as outlined in ISO 12100, ISO 14121, ISO 25119. The risk assessment process is used to quantify machine hazards and assign a safety metric for the Performance Levels for Agricultural Equipment (AgPL). The risk assessment determines the applicability of this EMC standard, and it defines testing modes and allowable responses observed during testing.
The AgPL performance level rating depends on a number of factors, these include:
- The severity of injuries associated to various machine operations or to a particular machine safety control system,
- The probability of occurrence of the hazardous event, and
- The possible aversion of the hazard through controllable mitigating steps.
For example, ISO DIS 14982-2:2021 is only relevant for functions of machine control system failures that are greater than or equal to AgPLr “b” (or the equivalent) when risk-assessed to ISO 25119 (or the equivalent) when other electronic functional safety standards are used,
No official date has been announced for the OJEU publish date of the new 2021 draft standards, but by testing to the 2021 draft, manufacturers can assess their products in a manner reflecting the state of technology and will be assured continuity with compliance requirements to come.
(EU) 2015/208 Ag & Forestry Tractors
The on-road regulatory EMC requirement for Ag and Forestry “tractors” is (EU) 2015/208 (supplementing Regulation EU No 167/2013). Ag and Forestry tractors within scope of this regulation are required to be assessed through type approval and certified through a European Notified Body. The EMC requirements in EU 2015/208 have been amended to allow testing to UNECE Regulation 10(Rev 4), or EN ISO 14982:1998, or EU 2015/208. The selection of the applicable test standard, test modes, and allowable tractor performance is reviewed and agreed to by the manufacturer and the Notified Body. In addition, the manufacturer must consider tractor operations that are both within scope of regulation EU No 167/2013 and any machinery functional safety concerns within scope of the Machinery Directive.
EN ISO 13766-1: 2018 Earthmoving and Building Construction Machinery
This is the published EN harmonized standard listed in the OJEU for the EMC Directive. It is an EMC Directive only standard that sets the emissions requirements plus it includes immunity testing for machine operations and ESAs that do not have a safety related function. This standard replaced EN 13309:2010, which means equipment that has previously been tested per EN 13309 is no longer afforded the presumption of conformity and should be re-assessed to EN ISO 13766-1:2018.
EN ISO 13766-2:2018 Earthmoving and Building Construction Machinery
This is the published EN harmonized EMC standard listed in the OJEU for the Machinery Directive and covers immunity only testing. It specifies additional requirements related to the functional safety of machinery and its electrical systems along with separate ESAs.
Like the Ag/forestry functional safety draft standard, it introduces the concept of applying machinery risk assessments and evaluating safety related parts of control systems. For construction machinery applications, the safety processes outlined in ISO 13849 apply with the goal of determining the performance level (PL) metric. EN ISO 13766-2:2018 is relevant for machine control system failures which when risk assessed are greater than or equal to PL “b” (or the equivalent).
EMC for Functional Safety -- Five Take-Aways
Given the complexity of heavy machinery and its conformity assessment, along with the range of directives, regulations, and standards, we conclude with the following take-aways.
- The applicable EMC testing requirements for functional safety should be based on the hazards risk assessment performed by the machinery manufacturer. In addition, the risk assessment will define the modes of operation and performance acceptance criteria.
- Machine operations and safety-related control systems that are rated at a safety Performance Level (typically PL b) or higher need to comply with the EMC standards listed in the OJEU for the Machinery Directive.
- There are three Ag and forestry EMC standards and versions to consider as applicable conformity assessment technical requirements. The standard EN ISO 14982:2009 is the current regulatory requirement for EMC and Machinery Directive. The new draft standards are voluntary, but they cover the requirements in the 2009 edition, provide a more robust EMC evaluation, and provide continuity in compliance when the 2009 edition is withdrawn. Testing to the newer draft standards may not involve a significant increase in compliance testing cost.
- Ag and Forestry Tractors are type approved and E-Marked for compliance in Europe. In addition, certain tractor mechanical functions and control systems may also be assessed under the CE Marking Machinery Directive.
- For electronic sub-assembles that are incorporated in all three classes of equipment mentioned (Ag/forestry, Earthmoving/Construction, and Tractors) a single suite of EMC tests can be defined in a test plan to cover all applications.
Next Steps – Start Planning Your Test
Industry trends have raised the importance to heavy-machinery manufacturers of EMC testing for functional safety. Increasingly, there are more electronic controls operating machine functions, wireless technology has become more prevalent, and operators are becoming more reliant on automated or autonomous operation. To address these challenges, regulatory requirements and testing standards have adapted to technology with more robust emissions and immunity testing.
To determine which standards apply to your product, contact Elite and speak with an EMC expert to learn more. Elite will guide you through the regulations, standards, and testing processes you need to get to market.