Calibration and Specification Considerations When Using Modular Instrumentation
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Transcript of Calibration and Specification Considerations When Using Modular Instrumentation
Calibration and Specification Considerations
When Using Modular Instrumentation
Mike Dobbert
Environmental ConditionsOperating SoftwareMulti-module Instruments
Modular Instruments
Configuration FlexibilityInterchangeabilityMeasurement SpeedSize
Traceable Measurements!(calibration required)
Modules have neighbors.
Environmental Conditions
Fixed Configuration.
Ambient environmental conditions are a good predictor of the internal operating conditions.
Environmental Conditions
Environmental Conditions
Calibration Laboratory
Ambient environmental conditions outside the chassis are not necessarily a good indication of the internal operating conditions!
Environmental Conditions
Environmental Conditions
Environmental Conditions
Instrument Drivers (reside outside the module)Installed Drivers at the Calibration Laboratory
Ideally, the same software driver revision is used for both calibration and during intended operation.
Operating Software
Operating Software
Set of modules working together as a single instrument.Instrument accuracy may depend on more than one module.
Multi-Module Instruments
Calibrate the multi-module instrument as a single instrument.Multi-module instruments require a unique identification(when calibrated as a set).
Calibration Manager
Multi-Module Instruments
Multi-Module Instruments
Model multi-module instruments as a function of individual modules.
(GUM method of uncertainty propagation.)
Multi-Module Instruments
Multi-Module Instruments
𝒚=𝒇 ( 𝒙𝟏 , 𝒙𝟐 ,𝒙𝟑 )
Tradeoff: modular flexibility versus accuracy.
In-Situ Calibration
Address environment and controlling software issues.
Conclusion
Environmental Conditions
Module environment highly dependent on system configuration.
Operating Software
Instrument driver resides outside the module.
Multi-module Instruments
Calibration of a set of modules. Calibration of individual modules
utilizing the method of the GUM.