Vibration sensor NVT/S3 PLd


Catalog excerpts

Vibration sensor NVT/S3 PLd - 1

■ Contactless, wear-free sensor system in MEMS technology ■ Number of measurement axes: 2 ■ Frequency range: 0.05 ... 60 Hz ■ Measuring range: ± 2 g ■ Special features: ♦ Various signal settings: RMS, PEAK ♦ In addition: signal output on PROFINET standard protokol (grey chan.) Design The sensor system is intended as a component for use e.g. in wind power plants to measure and evaluate vibrations in the mast head. Registration of dynamic accelerations by means of MEMS sensors (Micro-Electro-Mechanical System) with subsequent digitisation by a controller. The device consists of an acceleration sensor, a controller unit and the output interface PROFIsafe over PROFINET for output of the acceleration values. Thanks to its high resistance to vibration and shock - more than the defined measuring range -, the sensor is suitable for use in areas with rough environmental conditions. Electrical connection is carried out using three connectors. 5 LEDs help at installation and diagnosis of NVT90/S3. Function MEMS sensors are integrated circuits which are manufactured in silicon bulk micromechanics technology. They have a long service life and are very robust. After determining the steady component and scaling, the measured values supplied by the acceleration sensor are made available to the filter units. The steady component arises as a result of installation which is not precisely horizontal, with the result that part of the earth's gravitational field would also be measured. The offset which occurs in the measured vibration value curve (zero point shift) due to the steady component is determined by means of calculation (distribution of the positive and negative measured values around the zero point) and is subtracted. The pure alternating component is output within a matter of 30 seconds. This calculation takes place continually. This function can be shut off in the factory. The filter units can be individually programmed in the filter characteristics for frequency selection in the factory (low pass, high pass or band pass). They can be assigned to the horizontal axes (usually called x and y) also to the resulting ones. The signals which are then available can be used for: ♦ output on PROFIsafe over PROFINET ♦ output on PROFINET standard protokol ♦ calculation of momentary or RMS output or peak or integral output The Profinet interface according to IEC 61158 / 61784 or PNO specifications order No. 2.712 and 2.722, version 2.3, is integrated into the series NVT. Real time classes 1 and 3 are supported, i.e. Real Time (RT) and Isochronous Real Time (IRT) plus the requirements of conformance class C.The integrated 2-fold switch enables the TWK PROFINET inclinometer to be used in star, tree and line network topologies. The PROFIsafe protocol is implemented according to the PROFIisafe Profile for Safety Technologie version 2.4 (PNO Order No. 3.192). An exhaustive description of integration into a PROFINET network can be found in the NVT14588 manual. PROFINET properties - Real Time (RT) and Isochronous Real Time (IRT) - Device exchange without interchangeable medium or programming device - Prioritised start-up (Fast Start Up) - Media redundancy possible - Firmware update via Profinet TWK-ELEKTRONIK GmbH BismarckstraBe 108 visit us at |

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Vibration sensor NVT/S3 PLd - 2

Vibration sensor / monitor NVT / S3 Description General information The vibration sensor measures on two axes in a frequency spectrum from 0.05 to 60 Hz. These two axes are located parallel to the mounting surface of the NVT90. This spectrum can be subdivided into a maximum of 6 frequency ranges. The frequency ranges are set in the factory. All acceleration values acting within the relevant frequency window are registered and are output as a digital value via PROFIsafe over PROFINET. The measuring axis is x and y (partly called y and z) or the vector sum √(x²+y²) built from x and y. The...

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Vibration sensor NVT/S3 PLd - 3

Vibration sensor / monitor NVT / S3 Examples for fiter output - Chebichev The time lag in seconds (y axis) is entered over the applied frequency f (x axis). The different diagrams apply to the different upper frequency limits fo of a filter (fo is set in the factory → filter pass behaviour → low-pass high-pass - band-pass). Rough calculation of tV: tV = ~1/(fo*2) + 16 msec. with fo = upper frequenz edge (+16 ms due to prefiltering). Filter setting 0,1 Hz to 1,5 Hz Examples for fiter output - 0.05 - 5 Hz with SCS, prefiltering, Butterworth 5 Hz Steady component suppression (SCS) - Magnitude

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Vibration sensor NVT/S3 PLd - 4

Vibration sensor / monitor NVT / S3 Examples for fiter output - 0.05 - 5 Hz with SCS, prefiltering, Butterworth 5 Hz Steady component suppression (SCS) - Phase Prefilter - Magnitude

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Vibration sensor NVT/S3 PLd - 5

Examples for fiter output - 0.05 - 5 Hz with SCS, prefiltering, Butterworth 5 Hz Date: 23.04.2019 Page 5 of 12 Document No. NVT 14587 FE

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Vibration sensor NVT/S3 PLd - 6

Vibration sensor / monitor NVT / S3 Examples for fiter output - 0.05 - 5 Hz with SCS, prefiltering, Butterworth 5 Hz Mainfilter, Butterworth 2nd order - Phase Frequency detection by Fourier transformation FFT In preparation is an NVA version which provides the output of the spectrum of measured frequencies via PROFINET. This spectrum is get by Fourier transformation (FFT) of the momentary value of the acceleration measurement versus time. This functionality can be used for blade or tower frequency detection. See two simple examples for such a transformation in the following diagrams....

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Vibration sensor NVT/S3 PLd - 7

Vibration sensor / monitor NVT / S3Technical data Input data * ■ 2 byte status word ■ 3x2 byte position data Output data * ■ 2 byte control word Electrical data ■ Sensor system: ■ Number of frequency bands: ■ Measuring range: ■ Sampling frequency: ■ Resolution: ■ Operating voltage range: ■ Power consumption: ■ Current consuption: ■ Maximum inclination vs. horizon: ■ Sign of output data: ■ Electrical connection: Environmental data ■ Operating temperature range: ■ Resistance to shock: ■ Resistance to vibration: ■ Protection type (DIN 40 050): ■ EMC: (Only use shielded cable for power supply...

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