Descriptors for trending
Goodbye to the frustration of monitoring the Balance-of-Plant (BOP) and lower critical machines. This type of machine is frequently difficult to identify and diagnose potential problems, especially with the low-bandwidth periodic data handed by most existing systems. The descriptor in VCM-3 is made by post-processing raw vibration signals (detectors) into one or further scalar values.
The descriptor values are veritably suitable for long-term trends to indicate the failure mode of each machine. The VCM-3 measures a variety of descriptors similar to real-time standardized bandpass filters for true energy measurement, and envelope bandpass for bearing fault discovery.
Where are descriptors used? How are they created?
Descriptors can be part of any condition monitoring solution and are the “heart of asset reliability”. They carry solid information about “asset health” within the factory. For example, our innovative EDGE device VCM-3 can be described as the “mother” descriptor.
Within the VCM-3, descriptors are created by processing the “raw” time signals handed by sensors connected to the VCM-3. This happens continuously (ONLINE) and depending on the power of the VCM-3 processor and customizable configurations, an unlimited number of descriptor types can be created, processed, and used to monitor assets in your factory.
Where does the descriptor come from?
Each” type descriptor” needs to be specified. It’s veritably easy, to use a structured approach based on the type of asset to be monitored. The different types of assets in your factory, similar to pumps, are built from individual factors, similar to shafts, couplings, gearboxes, and rolling element components. Each asset is first mapped through its mechanical components.
The coming step is to produce descriptors that map the typical failure modes associated with each component, similar to rolling element-bearing faults. An example of a failure mode could be an “outer ring fault” of a rolling element bearing. Once each failure mode has been defined and configured, a “template” is generated, which can be uploaded to the VCM-3 and your Condition Monitoring begins.
What are the benefits of using descriptors?
Descriptors are created to minimize the need for experts to spend time evaluating time waveforms, spectra, or Fast Fourier Transforms (FFTs) by assigning a potential failure mode to a single descriptor.
Each failure mode descriptor can be used for trend generation and alarm limits can be set, e.g. alert, danger, etc.
This occurs either within the CM system or by exporting descriptors and alarms to another plant system (similar to Historian, SCADA, or DCS, a third-party IoT supplier) that can reuse them fluently.
This trend allows you to see how the “state of your component” is decreasing. By combining different descriptors with process inputs and indeed other descriptors, new insights can be generated to catch previously undetected errors represented again by a single descriptor.
By comparing trends to alarm limits, “actionable insights” are generated that provide base decision-making that is understandable to non-experts.
What’s more, by applying further statistical analysis, the descriptors can be used as a basis for predicting how a particular fault will develop over time, looking into the future. This allows for an approximate assessment of the “remaining useful life” of your components.
Source : www.bkvibro.com