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Australian Government: National Measurement InstituteAustralian Government: National Measurement Institute
National Measurement Institute
      

Pattern Approval Performance Testing

Performance testing is carried out to determine the accuracy, functionality and reliability of instruments, e.g. flow rate testing for liquid measuring instruments and eccentricity for weighing instruments. In addition, testing is performed to ensure that instruments can continue to meet accuracy requirements when exposed to a range of conditions designed to replicate conditions in the field. These conditions are called influence factors and disturbance.

Influence Factor Testing

The National Measurement Institute (NMI) has four programmable environmental test chambers for testing to IEC 60068 temperature and humidity, or similar standards.

Temperature

Temperature testing can be controlled for low temperatures to –25°C and high temperature of +70°C. The environmental test chamber control system can apply a limit to the rate of temperature change.

Humidity

Two environmental test chambers provide damp heat humidity testing, which can be controlled with a relative humidity of up 95% using an injected water vapour (steam and cold water misting). Steady-state (no condensation of water on equipment) and cyclic (water condenses on the equipment) humidity testing types can be performed.

Power Variation Testing

Power variation testing can be conducted to an upper limit of 110% and a lower limit of 85% of the nominal AC voltage rating. Power variation for DC voltages can also be tested for battery operated equipment (IEC 61000-4-11).

Disturbance Testing

Radiated Interference

The anechoic chamber is 9 m long, 6 m wide and 4.5 m high.

Our automated electromagnetic susceptibility facility has the capacity to test for immunity to radiated interference over the frequency range 26 to 2000 MHz and at electromagnetic field strengths up to 3 V/m or 80 to 2000 MHz and at electromagnetic field strengths up to 10 V/m (IEC 61000-4-3).

Our automated electromagnetic susceptibility facility has the capacity to test for immunity to conducted radio-frequency field strengths over the frequency range 26 to 80 MHz and at electromagnetic field strengths up to 10 V/m (IEC 61000-4-6).

Line-borne Interference

An interference test system is used to test for the effects of short-time power reductions, AC mains voltage dips and short interruptions, and electrical bursts at voltage levels from 500 to 4 000 V and for frequencies equal to and below 5 kHz (IEC 61000-4-4 and IEC 61000-4-11) and surge immunity testing (IEC 61000-4-5).

Electrostatic Discharge

An electrostatic discharge simulator is used to apply electrostatic discharges from 2 kV to 8 kV for air or contact discharges applied to the instrument, or 2 kV to 6 kV discharges indirectly applied through horizontal and vertical coupling planes. Testing is carried out to IEC 61000-4-2.