On-site EMC testing

现场EMC测试

On-site EMC testing，现场EMC测试。所谓现场测试（也称为外场测试），就是将EMC测试仪器搬运到产品工作的现场进行的测试。例如大型医疗设备或系统（如核磁共振， 数字 X 射线，伽马射线等医疗设备） 由于尺寸较大、 运输不便、 安装相对固定、 额定供电电流大等特点，往往无法在实验室内完成电磁兼容测试。又如风力发电机，因该类产品体积庞大，且需要风力才能正常工作，EMC测试就必须在风力发电机安装的现场进行。

EMC测试中，屏蔽室和电波暗室是必备的测试场地，但随着中国出口业的发展，越来越多大型的设备在出口时需要进行电磁兼容性的测试，如CE-EMC或者FCC。这些大型设备由于体积大，或者重量超过了屏蔽室和电波暗室的承重，或者是需要水、风等外力驱动而无法在密闭的测试室中进行正常测试，这时候，就需要用现场测试的方法来评估EMC性能。

现场测试也称为On-Site test，现场测试对工程师的技术能力要求很高，不仅要熟悉标准的测试方法，对测试仪器也要非常熟悉，而且要有较强的协调和沟通能力，另外，还要对被测试的产品非常熟悉，才能在户外条件下尽快地完成测试。由于现场测试要将测试仪器搬运到被测产品工作的现场，仪器由于搬运和现场条件恶劣，被损坏的风险也较大，目前在国内有能力并且愿意执行现场测试的实验室还较少。

工业环境的EMC标准

需要现场测试的产品一般工作在户外较恶劣的环境中，申请CE-EMC指令测试时，一般我们建议选择工业环境的EMC标准：EN 61000-6-2:2005，EN 61000-6-4:2007+A1:2011，涉及的测试项目简单归纳如下：

No.	Test Item	Test Requirements
1.	Conducted Emission EN 61000-6-4 CISPR 16-1-1 as reference)	The EUT should be tested with the whole appliance active, including all modules, full load or at least appropriate load. Output lines( L1/L2/L3/N ), net cable, as well as power lines which can be connected to public power supply should be tested respectively.
2.	Radiated Emission EN 61000-6-4 CISPR 16-1-1 as reference)	The EUT should be tested with the whole appliance active, including all modules, full load or at least appropriate load. Four surfaces (Front/Rear/Left/Right) should be checked respectively.
3.	ESD immunity EN 61000-6-2 EN 61000-4-2 as reference)	The whole EUT should be active with appropriate load (such as 10% full load). Test Level: Conduct discharge: +/-4.0kV Air discharge: +/-2.0kV
4.	RF Electromagnetic Field Immunity EN 61000-6-2 EN 61000-4-3 as reference)	The whole EUT should be active with appropriate load (such as 10% full load). Four surfaces (Front/Rear/Left/Right) should be checked respectively. Level: 10V/m
5.	EFT immunity EN 61000-6-2 EN 61000-4-4 as reference)	The whole EUT should be active with appropriate load (such as 10% full load). Power supply, DC lines (>3m), net-cable (>3m) should be checked. Test Level: for input or output AC/DC lines: +/-2.0kV; other lines (Signal/net cable(>3m)): +/-1.0kV
6.	Surge Immunity EN 61000-6-2 EN 61000-4-5 as reference)	The whole EUT should be active with appropriate load (such as 10% full load). Test Level: L/N-PE: +/-0.5kV, +/-1.0kV, +/-2.0kV L-N: +/-0.5kV, +/-1.0kV Note: The test level should be performed from low to high
7.	Inject Currents Immunity, 0.15MHz to 80MHz EN 61000-6-2 (EN 61000-4-6 as reference)	The whole EUT should be active with appropriate load (such as 10% full load). Power supply, DC lines(>3m), net-cable(>3m) should be checked. Level: 10V/m
8.	Voltage Dips and Interruption Immunity EN 61000-6-2 (EN 61000-4-11 as reference)	The whole EUT should be active with appropriate load (such as 10% full load).
9.	示例	示例