Your process plant probably has some large items of rotating machinery that could benefit from vibration monitoring, or maybe you're contemplating such an installation. In either case, you now have the option of using your existing process historian as the front end for a vibration monitoring system.
"Historically, vibration data collection rates necessary to allow detailed machinery diagnostics were too fast for plant process historians, particularly when a system encompassed dozens or hundreds of vibration channels,” says Jonathan Fox, senior software development engineer at Metrix Setpoint.
"As a result, stand-alone vibration monitoring infrastructures evolved, with their own proprietary databases, servers, display clients, security models and network connections. However, as the capabilities of the OSIsoft PI System have improved, the ability to treat vibration waveforms as simply another type of time series data in the PI System database has become practical, and is already in use at multiple plant sites,” explains Fox.
This is a better approach for many companies. "Eastman Chemical has been an OSIsoft PI user for many years, and it's our standard process data historian,” notes Greg Bayne, control systems engineer with Eastman Chemical Co.'s Texas operations.
"Being able to mesh machine vibration with process data easily and to have that data time/date synchronized is very beneficial. Before, data had to be exported from the proprietary vibration system and manipulated to match up with the process data, making analysis of an event very tedious and difficult. We also have a tremendous amount of in-house support for PI, all the way from the server implementation to ProcessBook expertise,” adds Bayne.
To implement this concept, Eastman Chemical purchased a vibration monitoring system from Metrix for its plant in Longview, Texas. The system has about 80 vibration measurement points on six machine trains, including two centrifugal compressors, two centrifugal refrigeration compressors and two large, vertical, double-inlet centrifugal pumps.
Vibration proximity probe transducers on the machines are used for radial shaft movement detection at each bearing location, and for thrust monitoring of shaft axial movement on each separate case on the centrifugal compressors. Accelerometers are mounted on the gearbox housing to monitor case vibration.
These devices are connected with field wiring to the control room, where they terminate at the Metrix panel, which is connected to the plant's PI servers via Ethernet. The setpoint-to-PI-adapter software application written by Metrix transfers data to the PI system.
"The biggest challenge was optimizing data collection settings in the Metrix rack and PI compression settings to find a balance between minimizing collected data, while still acquiring meaningful waveform data. We initially collected massive amounts of data, but through several iterations we've found the right balance. Of course, this was with only one operating unit online, so we'll need to go through this process as we bring future Metrix systems online, but we've learned a great deal that should help with this process,” explains Bayne.
Although the Metrix hardware uses an open protocol and can communicate with most databases, the current focus is on integration with the OSIsoft PI system. "The PI system has the broadest customer base, and its database performance meets our needs. However, we've seen interest in integration with other systems, namely proprietary condition-monitoring software developed by turbo machinery OEMs. The way that data is collected in our hardware is the same for all applications, and all that's needed for communication with external systems is an Ethernet link and a small software program to translate the data into the correct database format,” says Fox.