#Gideros accelerometer Pc#

A typical general-purpose accelerometer is linear up to 50000 to 100 000 m/s 2, which is well into the range of mechanical shocks. The upper limit is determined by the accelerometer's structural strength. This limit is normally as low as one-hundredth of an m/s 2 with general-purpose instruments. The lower limit shown on the drawing is not normally determined directly by the accelerometer but by electrical noise from connecting cables and amplifier circuitry. When it is wished to measure abnormally low or high acceleration levels, the dynamic range of the accelerometer should be considered. Generally, the accelerometer mass should be no more than one-tenth of the dynamic mass of the vibrating part onto which it is mounted. Additional mass can significantly alter the vibration levels and frequencies at the measuring point. The mass of the accelerometers becomes important when measuring on light test objects. In normal circumstances, the sensitivity is not a critical problem as modern preamplifiers are designed to accept these low-level signals.

Ideally, we would like a high output level, but here we must compromise because high sensitivity normally entails a relatively big piezoelectric assembly and consequently a relatively large, heavy unit. The sensitivity is the first characteristic normally considered.

Other special-purpose types are optimized for simultaneous measurement in three mutually perpendicular directions high temperatures very low vibration levels high-level shocks calibration of other accelerometers by comparison and permanent monitoring on industrial machines.Īccelerometer Sensitivity, Mass and Dynamic Range An example small accelerometers that are intended for high level or high-frequency measurements, and use on delicate structures, panels, etc. Many of the accelerometers outside the general purpose range have their characteristics slanted towards a specific application. The low-impedance output allows you to use inexpensive coaxial cables for accelerometers. They are hermetically sealed to protect against environmental contamination, have low susceptibility to radiofrequency and electromagnetic radiation, and low impedance output due to the external constant current power source. These accelerometers are high-performance instruments that have higher output sensitivity than standard piezoelectric accelerometers (without integral amplifiers). The Brüel & Kjær Uni- Gain® types have their sensitivity normalized to a convenient 'round figure' such as 1 or 10 pC/ms -2 to simplify calibration of the measuring system.ĬCLD (Constant Current Line Drive) Accelerometers or IEPE (Integrated Electronics Piezo Electric) accelerometers are piezoelectric accelerometers with integral preamplifiers, which give output signals in the form of voltage modulation on the power supply line.īrüel & Kjær's IEPE accelerometers have a high output sensitivity, high signal-to-noise ratio, and wide bandwidth make them suitable for both general purpose and high-frequency vibration measurements.

#Gideros accelerometer Pc#

These are available with either top or side-mounted connectors and have sensitivities in the range from 1 to 10 mV or pC per m/ s 2.

Most manufacturers have a wide range of accelerometers at first sight, maybe too many to make the choice easy.Ī small group of 'general purpose' types will satisfy most needs. The Compression Type where the mass exerts a compressive force on the piezoelectric element and the Shear Type where the mass exerts a shear force on the piezoelectric element. This can be seen from the law, Force = Mass x Acceleration.įor frequencies lying well under the resonant frequency of the complete spring-mass system, the acceleration of the mass will be the same as the acceleration of the base, and the output signal magnitude will therefore be proportional to the acceleration to which the pick-up is subjected. In practical accelerometer designs, the piezoelectric element is arranged so that when the assembly is vibrated the mass applies a force to the piezoelectric element which is proportional to the vibratory acceleration. When it is mechanically stressed, either in tension, compression, or shear, it generates an electrical charge across its pole faces which is proportional to the applied force. The heart of a piezoelectric accelerometer is the slice of piezoelectric material, usually an artificially polarized ferroelectric ceramic, which exhibits the unique piezoelectric effect. They are capable of operation at extreme temperatures but are constrained by high output impedance requiring low-noise cables and charge amplifiers to condition the signal. There are no moving parts to wear out, and finally, its acceleration proportional output can be integrated to give velocity and displacement proportional signals. A piezoelectric accelerometer is self-generating so that it does not need a power supply.