ISO 8041-2:2021 pdf download – Human response to vibration —Measuring instrumentation 一Part 2: Personal vibration exposure meters.
For type approval and periodic verification, the instrument shall display the frequency-weighted acceleration values.
The display device(s) specified In the instrument documentation shall permit displayed measurement values with a resolution of not more than 1 % of the indicated value.
Within the prevailing environmental conditions, the time interval required for stabilizing and being ready to use shall be documented.
For instruments that can display more than one measurement quantity, a means shall be provided to ascertain clearly the measurement quantity that is being displayed, preferably indicated by standard abbreviations or letter symbols.
The quantities that can be displayed by the PVEM shall be described in the instrument documentation. along with a description of the corresponding Indications on each display device.
When results of a measurement are provided at a digital output, the instrument documentation shall describe the method for transferring or downloading the digital data to an external data storage or display device, e.g. a computer. The instrument documentation shall identify the software as well as the hardware for the interface. Internationally standardized interface bus compatibility is recommended.
For instruments with digital display devices updated at periodic intervals, the indication at each display update shall be the value of the user-selected quantity at the time of the display update. Other modes of indication at the time of the display update may be Identified In the Instrument documentation and, if so. the operation of such modes shall be explained in the instrument documentation. The instrument documentation shall state which modes conform to the specifications of this document and which do not conform.
5.3 Electrical output
No AC electrical output for PVEM is required.
5.4 Vibration sensitivity
The instrument documentation shall specify at least one model of field vibration calibrator as a means to check and maintain the mechanical sensitivity of the PVEM. The field vibration calibrator shall conform to the spec.ficatlons given in ISO 8041-1:2017, Annex A. The manufacturer shall describe the attachments and jigs used with the vibration calibrator in the instruction manual.
The Instrument documentation for the vibration Instrument shall describe the procedure for adjusting the indicated vibration to conform to the specifications in this document by application of the specified field vibration calibrator. The adjustment shall apply to the models of vibration transducers recommended in the instrument documentation For use with the PVEM. The adjustment shall also apply to any cables, connectors and other accessories provided by the manufacturer of the instrument for connecting a vibration transducer to the instrument.
5.5 Accuracy of indication at reference frequency under reference conditions
The requirements for tolerance of the displayed results are given in Table 2. The tolerance of indication is specified at the appropriate reference frequency and reference vibration value specified in TahieJ with the instrument switched to the reference measurement range, with sinusoidal mechanical vibration applied to the base of the vibration transducer or specified mounting device. The requirements apply to all frequency weightings specified in this document and after applying adjustments described in £4 and after the specified stabilization time interval has elapsed.
The tables and weighting curves given in IS0 8041-1:2017,Annex B, illustrate the magnitude and phaseof the frequency weightings defined by Formulae (1] to [5) and Table 3, as functions of frequency,f.lf a PVEM provides one or more optional frequency responses, the instrument documentation shallstate the design-goal frequency response and the tolerance limits that are maintained around thedesign goal[s). If an optional frequency response is specified in an International Standard, the design-goal frequency response shall be as specified in that International Standard.
The filters defined by Table 3 and Formulae (1) to (5) may be realized by combinations of simpleanalogue filters. 1IS0 8041-1:2017,Annex C, provides an example of how the frequency weightings canbe realized digitally in the time and frequency domains.
5.6.6 Tolerances
The tolerances on the frequency weightings are given in Tables 4 and 5.The tolerance limits in Table 5apply to the weightings,including the corresponding band-limiting weightings, on all measurementranges.Tolerance limits include the applicable maximum expanded uncertainties of measurement.