CENTURY WIDOM

Wisdom

图片名称

CN

图片名称

English

图片名称

Search

Technical column

CASES

图片名称

Changes in Medical Electrical Equipment IEC60601-1-2-2014A1-2020 Revision

Release time:

2023-09-20 15:55

Source:

　　1 Foreword

In September 2020, IEC issued the first revision IEC60601-1-2 of the electromagnetic disturbance requirements and test standard for medical equipment IEC60601-1-2:2014: 2014/A1:2020. The revised version is version 4.1. This article will briefly introduce the main contents of the revision for reference.

　　2 Revision of test requirements

Revision of the supply voltage of the device under test in 2.1

The "Table 1" in the standard lists the requirements for the power supply voltage and frequency of the equipment under test. The 4.1 version has modified the requirements for the power supply voltage of the two items of conducted emission, voltage drop and terminal.

The standard cited for the conducted emission test in "Table 1" is CISPR 11: 2019, and the supply voltage of the device under test is modified from any voltage within the rated voltage range of version 4 to the maximum minimum rated voltage, unless the difference between the maximum and minimum rated voltages is less than 25% of the maximum rated voltage. The examples and calculation of the commonly used power supply voltage of the device under test are shown in Figure 1. Under normal circumstances, the voltage range of the device under test is illustrated in Figure 1. The values listed in this table can be used as reference before testing.

Figure 1 Example of whether a conducted emission test at a single voltage is permitted

The reference standard for the voltage drop test in "Table 1" is IEC 61000-4-11: 2004, and the supply voltage of the device under test is modified from any voltage within the rated voltage range of the 4th edition to the maximum minimum rated voltage, unless the difference between the maximum and minimum rated voltages is less than 25% of the maximum rated voltage. The same as the conducted emission test, the judgment method can also refer to the relevant content in Figure 1.

Revision of 2.2 Power Frequency Magnetic Field Test Level

The power frequency magnetic field test of "Table 4" in the standard cancels the requirement of 15cm distance in the 4th edition. In the 4th edition, it is required that for equipment less than 15cm from the magnetic field source, additional evaluation is required to determine the test level. In the 4.1 edition, no further evaluation is required, and the test level of 30A/m is sufficient.

Revision of 2.3 Conducted Immunity Test Requirements

The conducted immunity test of "Table 8" in the standard cancels the requirement that input and output cables less than 3m can be exempted from the test, and changes the exempted length to less than 1m, and adds the requirement of IEC 61000-4-6: 2013 to calculate the test starting frequency through equipment size and cable length.

2.4 New Test Item-Close Range Radiation Field Immunity Test

The short-range radiation field immunity test is a new test item in the 4.1 version of the standard. "Table 1" adds the test voltage requirements for the short-distance radiation field immunity test project. The reference standard is IEC 61000-4-39: 2017. The test can be carried out at any voltage and any frequency.

　　3 Newly added close radiation field immunity test

Experimental sources of 3.1 close radiation fields

The new 4.1 version of the standard refers to the IEC 61000-4-39: 2017 standard, adding the test items of the close radiation field. The reason for the increase is that the close radiation sources in the medical environment and the domestic environment are gradually increasing, and the electronic circuits or components contained in the medical electrical equipment may be sensitive to the radiation of these sources, which will produce certain risks.

Evaluation Method of 3.2 Radiation Field Immunity Test at Close Range

The IEC 61000-4-39: 2017 standard contains tests in four frequency bands: 9~150kHz, 150kHz ~ 26MHz, 26MHz ~ 380MHz and 380MHz ~ 6GHz. The 4.1 version of the standard only uses the first two frequency bands, that is, the loop antenna is used for testing in the 9kHz ~ 13.56MHz frequency band.

Not all medical equipment needs to undergo this new test. The 4.1 version of the standard provides an evaluation procedure for whether the tested equipment needs to apply the short-range radiation field immunity test. The specific evaluation steps are divided into the following four categories: A, B, C and D:

A. For medical electrical equipment or systems or accessories that do not contain magnetically sensitive components or circuits in their enclosures, it is not necessary to evaluate the immunity to short-range radiated fields from 9kHz to 13.56MHz;

B. Medical electrical equipment or systems containing magnetically sensitive components or circuits that are at least 0.15m away from the emission source specified in "Table 11" and that can be maintained in intended use by the physical design of the enclosure or accessories without the need to evaluate the 9kHz to 13.56MHz close range radiated field immunity;

C, the distance between the medical electrical equipment or system and the emission source specified in the "Table11" is less than 0.15m, if the risk analysis believes that this exposure phenomenon can be accepted in the expected use, it is not necessary to do the close radiation field immunity test;

D. If the medical electrical equipment or system containing magnetic sensitive components or circuits does not meet the distance requirements in (B) or the risk acceptance criteria in (c), the short-range radiation field immunity test shall be carried out. The test method uses the method in IEC 61000-4-39: 2017. During the test, the magnetic field only acts on the surface of the housing or accessories that can be contacted during the intended use, the test window only irradiates the area of the magnetic sensitive component or circuit, and the position of the applied magnetic field needs to be written into the test plan and test report.

Only (d) of the above four cases needs to be tested, and whether to perform the short-range radiation field immunity test can also be judged with reference to the process provided in fig. 2. In general, not all ME equipment is subject to this test, and the standard provides exemptions or requires documentation. But manufacturers can also choose not to exempt directly to do the test.

Fig. 2 Evaluation Steps of Close Radiation Field Immunity Test

Magnetic sensitive elements and magnetic sensitive circuits are mentioned in the evaluation method. Magnetic sensitive elements include coils, signal transformers, and Hall effect sensors. The magnetically sensitive circuits include the following:

1) Analog signal circuit, the passband is within the frequency range specified in the test, and the circuit is surrounded by interconnection paths, so that the induced voltage will interfere with the signal;

2) A digital circuit in which the induced voltage is close to the logic unit in the interconnection circuit;

3) The external pacemaker system, the lead and the temporarily implanted heart wire form a loop, and its area is sufficient to generate induced voltage.

In the case (B), the value of the minimum distance is set to 0.15m. The setting of this value takes into account the types of adjacent magnetic field interference sources, including the following:

1) Induction cooking appliances and ovens with working frequency up to 30kHz;

2) RFID reader with working frequency of 134.2kHz and 13.56MHz;

3), electronic anti-theft system;

4), sponge detection system;

5) Equipment for position detection (e. g. in the causeroom);

6) The working frequency is in the range of 80~90kHz, which is used for wireless power transmission and charging system of electric vehicles.

The size of the coil used by the above interference sources is usually not more than 0.06m. Through calculation, it can be concluded that the magnetic field can attenuate to 5% or less of the maximum magnetic field outside the distance of 0.15m. Therefore, 0.15m is selected as the judgment distance.

3.3 Test requirements for near field immunity tests

Three frequency points (30 kHz, 134.2 kHz and 13.56 MHz) in the frequency band from 9 kHz to 13.56 MHz were selected for the test, as shown in Figure 3.

Fig. 3 Requirements for immunity test level of short distance radiated field

In the frequency range of 9 to 150kHz, the risk of close radiation mainly comes from induction cookers and wireless charging equipment for emerging electric vehicles. Induction cookers have many operating frequencies, and the 4.1 version of the standard selects a single, known highest operating frequency (30kHz), simplifying testing. The operating frequency range of electric vehicle charging is 50~100kHz, but after testing, it is found that the field strength outside the vehicle will not exceed 12A/m when charging, and the field strength level is lower than that of the pulsed magnetic field emitted by the electronic anti-theft system and the radio frequency identification system. Therefore, if the charging frequency of electric vehicles is lower than 100kHz, no additional testing is required. The test field strength used at 134.2kHz and 13.56MHz frequencies is the external field strength of analog electronic anti-theft system and radio frequency identification equipment, the test field strength at 134.2kHz is the field strength 0.025m from the radio frequency identification reader, and the test field strength at 13.56MHz is the field strength 0m from the radio frequency identification reader.

　　4 Appendix A Revision of General Guidelines and Rationale

Examples of 4.1 non-ME equipment

Examples of non-ME equipment in ME equipment are given. For emission, if non-me equipment is used in the ME system, the non-me equipment shall meet the same emission requirements as the ME system. In terms of immunity, it is necessary to consider whether the failure or degradation of non-ME equipment will cause the loss of basic safety or basic performance of the ME system. If the failure or degradation of non-ME equipment may cause the loss of basic safety or basic performance of the ME system, the immunity level specified for the ME system also applies to non-ME equipment, compliance with product standards for non-me equipment is sufficient if the failure or degradation of the non-me equipment does not result in loss of basic safety or essential performance of the me system.

EMI testing of large equipment 4.2 permanent installation

Permits on-site EMI testing of large, permanently installed medical devices and medical systems at responsible parties, which by definition do not include the manufacturer (e. g., hospitals, clinics). Appendix A explains that testing at the manufacturer's site can be considered equivalent to testing at the responsible party's site, but it needs to explain the appropriate reasons for testing at the manufacturer's site.

　　5 Summary

The 4.1 edition of IEC 60601-1-2 is a relatively large revision six years after the release of the fourth edition of the standard, which adds certain restrictions to the test voltage of the tested article. Test methods for large permanently installed equipment are also analyzed, and an alternative to factory installation is proposed, taking into account the limitations of field testing at the final installation site. The most important thing is to increase the close radiation field immunity test, test methods and test equipment are different from the previous radiation immunity test, the relevant practitioners need to learn new test methods, new test research.

　　

If you need more information about electromagnetic compatibility test equipment, you can visit the company's website http://www.emc-mall.com/查看 。

Century Wisdom (Suzhou) Testing Technology Co., Ltd

Business License
全部
  • 全部
  • 产品管理
  • 新闻资讯
  • 介绍内容
  • 企业网点
  • 常见问题
  • 企业视频
  • 企业图册
Search