Vibration Monitoring System

Recently, we implemented vibration monitoring systems (VMS) as well as condition monitoring systems (CMS) for our multiple projects. The application requirements varied for different projects, thus necessitating the supply of a variety of protection systems.

VMS system consists of following type of sensors:

• Vibration sensors (mV signals for CMS) from Bentley Navada, Hansford, B&K Vibro, and Vibrasens
• RTD for bearing, casing, and winding temperature measurements/protections (3-wire/4-wire).

At times, these sensors were provided with 4-20mA converters placed at sensor junction boxes. These JBs were installed at respective pump/motor. These sensors were further wired either directly to PLC/DCS or to VMS relays (MASIBUS 85XX++) to be independent from PLC/DCS. Dedicated protection trip signal was directly hardwired to VFD from Protection relay or PLC/DCS.

Various solutions implemented through PLC, DCS, and dedicated Masibus protection Relay. This solution is cost-effective compared to predictive API670 compliant system and provide adequate protection to the asset. Trending is available for all signals at SCADA systems for easy monitoring. This solution ensures assets are well protected, but failures cannot be predicted in advance.

Condition monitoring systems were implemented where drives were super critical and very large, requiring API 670 compliance. This necessitated wiring all vibration sensors to CMS using mV signals directly. mV signals provide multiple frequency spectrum analysis with different frequency amplitudes. this enables prediction of expected failures due to pump cavity, rotor bar, or bearing issues well in advance. However, this approach is quite costly, hence cost-benefit analysis is highly important. Temperature monitoring is primarily used for protection tripping only.

Prominent suppliers for CMS systems include #BentleyNavada (3500 series/Orbit 60 with System 1 platform), #Emerson A6500 with AMS Suit, #Meggitt VM600 with Vibrosight software, #NADA V-net 7000 series system with T-serves, #B&K Vibro VC8000 hardware with Setpoint software having OSI-PI & #SHINKAWA VM7 series.

Other solution implemented with nipples provision to fix vibration sensors at a later stage for both pumps and motors, providing loose vibration sensors with a portable shaker table & portable data collector for any machines where detailed analysis is needed and budget is a constraint. This is normally being implemented for small kW drives with less criticality.

VMS/CMS systems were integrated into PLC/DCS system over #redundant #Modbus TCP/IP for standard data transfer from rack to DCS as well as server-level integration over OPC. This provides full monitoring of machine condition on SCADA/DCS systems.

This experience was enlightening with rich learnings, offering multiple perspectives from different clients/vendors/projects. Reviewing multiple suppliers, their products, their SWOT, their handling of proposals, willingness to win, support to budget, soft term/ long term perspectives, rigidness or extended support during proposals and execution added lots of value in decision making.

Some constraints noticed include:

• kW rating mandating the use of VMS or CMS systems is subjective.
• The number of sensors is subjective, varying in different directions.
• If a vibration sensor is specified to be 4-20mA, supplying predictive analysis tools may not add much value.
• Commissioning services for these specific and monopolistic products can be costly.

I hope this article provides some important insights for you and proves to be a useful read.