IEC 60904-4 pdf free download

IEC 60904-4 pdf free download.Photovoltaic devices – Part 4: Photovoltaic reference devices – Procedures for establishing calibration traceability.
3.1
primary standard
standard that is designated or widely acknowledged as having the highest metrological qualities and whose value is accepted without reference to other standards of the same quantity
Note 1 to entry: The concept of a primary standard is equally valid for base quantities and derived quantities.
Note 2 to entry: A primary standard is never used directly for measurement other than for comparison with other primary standards or secondary standards.
Note 3 to entry: Primary standards are usually maintained by national metrology institutes (NMIs) or similar organizations entrusted with maintenance of standards for physical quantities. Often referred to also just as the ((primary)), the physical implementation is selected such that long-term stability, accuracy and repeatability of measurement of the quantity it represents are guaranteed to the maximum extent possible by current technology.
Note 4 to entry: The World Radiometric Reference (WRR) as realized by the World Standard Group (WSG) of cavity radiometers is the accepted primary standard for the measurement of solar irradiance.
3.2
secondary standard
device which, by periodical comparison with a primary standard, serves to maintain conformity to SI units at other places than that of the primary standard
Note 1 to entry: A secondary standard does not necessarily use the same technical principles as the primary standard, but strives to achieve similar long-term stability, accuracy and repeatability.
Note 2 to entry: Typical secondary standards for solar irradlance are cavity radiometers which participate periodically (normally every 5 years) in the International Pyrheliometer Comparison (IPC) with the WSG, thereby giving traceability to WRR. Direct traceability to SI radiometric scale can also be available for these instruments.
3.3
primary reference
instrument which a laboratory uses to calibrate secondary references, compared at periodic intervals to a secondary standard
4 Requirements for traceable calibration procedures of PV reference devices
A traceable calibration procedure is necessary to transfer calibration from a standard or reference measuring solar irradiance and based on a physical principle other than PV effect (such as cavity radiometer, pyrheliometer and pyranometer) to a PV reference device. The requirements for such procedures are as follows:
a) Any measurement instrument required and used in the transfer procedure shall be an instrument with an unbroken traceability chain.
b) A documented uncertainty analysis.
c) Documented repeatability, such as measurement results of laboratory intercomparison, or documents of laboratory quality control.
d) Inherent absolute accuracy, given by a limited number of intermediate transfers.
Normally the transfer would be from a secondary standard to a PV reference device
constituting a primary reference.
The transfer from one PV reference device to another is covered by IEC 60904-2.
5 Uncertainty analysis
An uncertainty estimate according to ISO/IEC Guide 98-3: 2008 shall be provided for each traceable calibration procedure. This estimate shall provide information on the uncertainty of the calibration procedure and quantitative data on the following uncertainty factors for each instrument used in performing the calibration procedure. In particular:
a) Component of uncertainty arising from random effects (Type A).
b) Component of uncertainty arising from systematic effects (Type B).IEC 60904-4 pdf download.