STREAM SHIELD – operational reliability patented
The technology STREAM SHIELD is an essential contributor to the extremely precise signal conversion achieved by the PR modules. STREAM SHIELD is a phase-locked login filter protecting the signal from external disturbances such as EMC noise and temperature fluctuations. We named the technology STREAM SHIELD since it functions as a protecting shield for the module. STREAM SHIELD is now a PR electronic A/S patent.
STREAM SHIELD minimises the risk of operating stops and thus increases productivity.
- High immunity to conducted current. The disturbance is caused by e.g. frequency converters or switch-mode current supplies. Our transmitters are tested against 10 V rms in the area 15 – 100 MHz, which is demanded by the maritime industry and others.
- High HF-noise immunityCellular phones, walkie-talkies, etc. create airborne disturbance. All transmitters are tested against 10 V/m in the prescribed area (80-1000 MHz) and thereby observe the NAMUR NE 21 A criterion.
- High immunity to high-energy transientsThe disturbance comes from e.g. contactors. Our transmitters are immunity tested against over voltage at a test voltage of 1 kV differential mode and 2 kV common mode (cf. NAMUR NE 21 A criterion).
- High burst immunityEffective protection against e.g. relay burst. To ensure a reliable production in areas with burst occurrences, we have decided to test the transmitters at 2,5 kV for 12 hours. Thus, we clearly live up to the NAMUR NE 21 A criterion which prescribes 2,0 kV for 1 minute.
- Extremely low temperature coefficientA high basic accuracy and an extremely low temperature coefficient make the PR modules state of the art according to the European standard IEC 68-2-1 / IEC 68 2-2 / IEC 770 6.2.10. A very important factor in obtaining a reliable thermometry.
Normally, the service technician or the process engineer is able to register temperature fluctuations and understand that they may have an impact on the signal. However, the invisible disturbances such as EMC noise are hard to observe and act upon. Nonetheless, this noise is often the cause of disturbance in the electronic equipment and thus, has a great impact on the process reliability.
The PR electronics standard specifications are carefully determined on the basis of both the EMC directive (EN 61326) and the somewhat stricter directive NAMUR NE 21 A criterion. Furthermore, our yearlong experience within the processing industry tells us that even products observing the NAMUR NE 21 A-criterion have turned out defective during operations. As a consequent, we raised our demands in connection with a number of products.
PR electronics A/S' standards for design-correct noise immunity:
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Test
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EMC Standard
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EMC spec.
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PR spec.
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PR criterion
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Deviation during test
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Noise of conducted current
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ENV 50141
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>10 V rms
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A
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< ±0,5 % of span
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HF noise
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ENV 50141
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10 V/m
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>10 V/m
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A
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< ± 1,0 % of span
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High energy transients
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EN 61000-4-5
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1 kV
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1 kV differential
2 kV common
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A
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< ± 1,0 % of span
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Burst
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EN 61000-4-4
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1 kV
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2.5 kV for 12 hours
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A
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< ± 1,0 % of span
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Criteria definitions
- The equipment has to continue its function appropriately during the test. The manufacturer defines the maximum deviation
- The equipment has to continue its function appropriately after the test
- Temporary loss of function is acceptable, provided that the function can be re-established automatically or by use of a control board.
In most cases PR electronics uses the A criterion, as the easier B and C criteria can result in temporary signal disturbances with direct impact on the process efficiency.
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