During the past several years the use of ultrasonic meters(USMs) has gained worldwide acceptance for fiscal applications.The many benefits of USMs have been documented in papers at virtually every major conference.The significance of knowing the ultrasonic meter is operating accurately has never been more important.The use of diagnostics to help identify metering issues has been discussed in several papers at many conferences[Ref 1,2 & 3].USM technology has played a key role in reducing Lost and Un-accounted For(LAUF) numbers.However,like any technology,the client must understand the meters'diagnostics in order to validate it is working correctly.Due to mergers,acquisitions,changes in technology,and purchasing preferences within an organization,it can be difficult for technicians to be skilled on all products.Also,changing technology adds to the difficulty as they often encounter multiple manufacturers'equipment.Most clients obtain diagnostic data(maintenance reports) by visiting the site monthly.This provides access to this data and a record of how the meter is performing at that time.However,this isn't an ideal situation,as the meter may not be flowing gas while the technician is on site.Additionally,a problem may occur in between inspections(usually monthly or quarterly),so the technician my never be aware of the issue.Thus,what is needed is a system that can monitor the USMs'health,regardless of manufacturer,and periodically,and automatically provide a single report to the client when problems occur.One method to resolve this issue is to have a real-time monitoring system that can provide monthly performance summaries(maintenance reports) and sends out text or email messages when any diagnostic parameter is out of range.This is generally difficult for most clients to do as measurement sites often have limited data bandwidth since the original purpose was to only collect flow rate data.This makes sending additional"diagnostic data"through the SCADA system much more challenging.A second issue is that the typical field flow computer,or RTU,may not have enough processing power to collect and analyze all of the USM data.A third problem is the variety of gas USMs on the market.Each one works on the same basic principle,but the diagnostics,and subsequent analysis techniques,vary from one brand to another.This makes it more difficult for the fiscal flow computer to be tasked with all this additional activity.A solution to this issue would be to have a separate system monitoring the facilities'diagnostics and reporting information using a separate data path independent of the clients'fiscal data.This paper discusses such a system.1.Typical USM Test or Verification Process For years the industry's paradigm for managing measurement risk has been to send technicians to the location to test and inspect the equipment.As measurement equipment has been modernized this task has become increasingly difficult.To test a modern measurement station a technician must not only be capable of operating the physical equipment at the station,he or she must also be proficient at connecting his or her laptop to the Flow Computer,USM,Chromatograph,and Transmitters.Of course they must be proficient in operating the vendor specific software programs,and in many cases,utilize them simultaneously.The technician typically tests equipment on-site such as the pressure and temperature transmitters.Highly trained technicians may recalculate volumes,briefly review USM Maintenance Reports and Chromatograph calibration records,and/or perform other tests such as running the calibration standard as an unknown.However,in most cases the technician collects data and then emails the data to Measurement Engineers and Analysts for further review.
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