IEC 61326-1:2020 pdf free download – Electrical equipment for measurement,control and laboratory use – EMC requirements
4General
Equipment and systems within the scope of this document can be subjected to various kindsof electromagnetic disturbances,sources of which include power，measurement or controllines or those radiated from the environment.The types and levels of disturbances depend onthe particular conditions in which the systems,subsystems or equipment are installed andoperated.
Equipment within the scope of this document can also be a source of electromagneticdisturbances over a wide frequency range. These disturbances can be conducted throughpower and signal lines, or be directly radiated,and can affect the performance of otherequipment, or influence the external electromagnetic environment.
For emissions,the objective of the requirements given in this document is to ensure that thedisturbances generated by the equipment and systems，when operated normally,do notexceed a level which could prevent other systems from operating as intended.The emissionlimits are considered in 7.2.
NOTE 1 Higher immunity levels than those specified can be necessary for particular applications (for example,when reliable operation of the equipment is essential for safety) or when the equipment is intended for use inharsher electromagnetic environments.Also，additional tests and different performance criteria can be necessaryfor particular applications.
NOTE 2 ln special cases, for example when highly susceptible equipment is being used near the EUT, additionalmitigation measures could have to be employed to reduce the influencing electromagnetic emission further belowthe specified limits.
The manufacturer may select to perform all tests on either a single EUT or divide the testsamong multiple EUTs. If the latter, each test result shall be traceable to the EUT tested.Thetesting sequence is optional.
5.2.1General
Measurement,control and LABORATORY equipment often consists of systems with no fixedconfiguration. The kind，number and installation of different subassemblies within the equip-ment may vary from system to system. Thus, it is reasonable, and also recommended， not totest every possible arrangement.
To realistically simulate EMc conditions (related both to emission and immunity)，theequipment assembly shall represent a typical installation as specified by the manufacturer.Such tests shall be carried out as TYPE TESTs under normal conditions as specified by themanufacturer.
5.2.2composition of EUT
All equipment, racks, modules, boards,etc. significant to EMC and belonging to the EUT shallbe documented. lf relevant, the software version shall be documented.
5.2.3Assembly of EUT
lf an EUT has a variety of internal and external configurations, the TYPE TESTS shall be madewith one or more typical configurations that represent normal use in the intendedenvironment. All types of modules shall be tested at least once. The rationale for thisselection shall be documented in the EMC test plan.
5.2.4vo PORTS
Where there are multiple l/O PORTs,which are all of the same type, connecting a cable to justone of those PoRTs is sufficient，provided that it can be shown that the additional cableswould not affect the results significantly.
5.2.5AUXILIARY EQUIPMENT
When a variety of equipment is provided for use with the EUT, at least one of each type ofequipment shall be seiected to simulate actual operating conditions.AUXILIARY EQUIPMENTmay be simulated.
5.3.2 Environmental conditions
The tests shall be carried out within the manufacturer’s specified environmental operating range (for example, ambient temperature, humidity, atmospheric pressure), and within the rated ranges of supply voltage and frequency. The requirements of IEC 61000-4-2 for environmental conditions shall take precedence over those of the EUT specification (for example the humidity requirements for ESD).