SPM Instrument's SPM HD measuring technique helps users identify weaker, yet relevant, signals
The SPM HD measuring technique is designed to be used in all types of applications, including low-speed machinery. By combining the True SPM method with a digital technique, SPM HD is engineered to identify the weaker, yet relevant, signals that are hidden amongst the stronger signals caused by mechanical shock phenomena or electronic noise. The technique works with digital enveloping of the analog shock pulse transducer signal. The sampling frequency is high, resulting in a distinct signal. A 24-bit A/D converter is designed to provide resolution and detail in spectrums and time signals.
The measuring cycle is based on number of revolutions rather than time. This is designed to maximize the chances of capturing relevant signals in the course of one measuring cycle. The measuring technique looks for recurring patterns and uses algorithms to enhance repetitive signals and eliminate randomly occurring high readings.
In addition to spectrum and time signal, the measuring technique also generates two scalar values, HDm and HDc. HDm represents the highest value measured during the measuring cycle, while HDc is a measure of bearing lubrication condition. Both values are suitable as the basis for setting alarm limits, regardless of machine type.