Validation and calibration

In metering systems, calibration of metering equipment often introduces a high cost of ownership, since all metering equipment at a minimum is to be periodically checked to proof overall system uncertainty.

With eXLerate based systems, validation and calibration procedures are fully integrated with the metering solution itself, ensuring a low cost of ownership.

Daily operation of the metering system continues normally while an isolated transmitter may be concurrently calibrated.

'As-Found' and 'As-Left' Validation procedures can be implemented with eXLerate for on-line flow computers, field transmitters, gas chromatographs, etc. For flow computers all implemented calculations may be re-evaluated at the supervisory level, such as AGA-3 or ISO-5167 based flow calculations, compressibility calculations using international standards like AGA-8, S-GERG, AGA NX-19 or ISO-12213.

Many additional thermodynamic property calculations of gases and liquids are available as well, such as dynamic viscosity, velocity of sound, heat capacity and isentropic exponent.

These validations allow for online checking of flow computer configuration and parameters.

Using dedicated CUSUM based performance monitoring functions, such as determination of long-term drift in transmitters or live VOS monitoring, the moment at which metering equipment must be recalibrated may be forecasted.

On-line validation and calibration procedures integrated in eXLerate for transmitters drastically reduce the time needed for a full calibration, while improving the quality of the validation or calibration process at the same time.

Our Validation Session Manager maintains an easy and graphically oriented overview of all concurrently running validation sessions, so that the operator has a convenient status overview of all ongoing validations.

Validations and calibrations may be executed semi-automatically with user interaction at several moments during the process, or even fully automatically.

An example of a semiautomatic validation procedure is a pressure transmitter connected to a remotely controlled deadweight tester where the supervisory computer presents results at the display page.

The status of the transmitter being in validation or calibration mode is automatically catered for in fiscal reports.

An example of a fully automated validation procedure is the validation procedure for a gas chromatograph, to which the supervisory computer periodically applies calibration gas via a solenoid operated valve, and generates a validation report at the end of the procedure.

Such automatic validation and calibration procedures may be executed during normal operation of the system.

Using the built-in relational database in eXLerate, all 'As-Found' and 'As-Left' validation and calibration results may be stored at the supervisory computer or (remote) corporate database server for permanent storage and statistical analysis at a later stage by a measurement quality department or metrology auditors.