Calibration Savvy

Calibration and Conformance  Calibration: Check a measurement against a known universally recognized standard to determine any deviation and correct for errors  Conformance: Check for agreement against internally defined values

THI Documents Certificate of Conformance Certificate of Calibration Combined Test Report Calibration Data Sheets – ALL THI metrology is NIST traceable NIST back up Documentation - $275.00

Certificate of Conformance Usually free!!

Certificate of Conformance Question #1: Can a customer receive a certificate of conformance on a gauge tube? Answer: Yes! We can verify that the tube’s output conforms to our acceptance criteria. *************************************************************************** Question #2: What other THI products could have a “C of C”? Answer: Any of our products that have some output (signal or visual indication) that we can verify against our acceptance criteria.

NIST Traceable Metrology

Calibration Report Question #3: Can a customer receive a calibration report for a gauge tube? Answer: No. We can combine the gauge tube with the customer's meter and cable and perform a calibration against our NIST standards, but we cannot calibrate just a gauge tube.

Certificate of Calibration ASK

NIST Back-up Documentation Provides the customer with copies of all of our calibration documentation related to the metrology used for their instrument’s calibration. In other words, THI has all of the calibration records for the metrology that we use.

NIST Back-up Documentation Note: Most of the time… the customer doesn’t need all of this!

Definitions  Accuracy: closeness of a measurement of a quantity to its actual value  Repeatability: the degree of change in a repeated measurement under the same conditions  Useful Measurement: Accurate and Repeatable

Error Calculation % Point =((IUT – STND)/ STND) * 100 Example for an HPM-760S: Standard (STND) = 1.00 Torr Instrument Under Test (IUT) = 1.01 Torr % Point = (( )/1.00)*100 = 1.0%

Full Scale Accuracy Calculation Accuracy as a % Full Scale = ((IUT – STND)/ FS) * 100 Example for an HFC-202: IUT = sccm Standard = sccm Full Scale of IUT (FS) = 100 sccm %FS = (( )/100)*100 = 0.02%

Accuracy Statements % FS (Full Scale) (HFC-202) % Reading (HPM-760) % Reading + % FS (HFC-D-302) % Reading + Constant (DVT, DAVC)

% of Reading (or % of Point) Internal ID

Common Questions:  What is the accuracy of my gauge tube?  Answer: Trick Question… need to know the instrument being used to measure gauge tube output.  Digital Gauges have stated accuracy… but what is the accuracy of an Analog Vacuum Meter/Controller (e.g. VT-6A or CVT-26A)?  Answer: Depends on the region of interest.

Accuracy: Response Curve

Reference Tubes What are they? - Evacuated/sealed glass gauge tube inside protective housing which simulate gauge tube output How are they used? – Allow the customer to verify the heater current to the gauge tube and the readout of the meter movement or digital display. Gives verification of the electronics and cabling – BUT tells nothing about the gauge tube connected to system.

Certificate of Calibration – Reference tube

Other Flow Calibrations Calibration Report Additional Points (10 points, 20 points, etc.) Multiple gas instances Polynomial Equation Manual Ordering power supplies with flow instruments

Other Vacuum Calibrations Specific Points on Data Sheet Calibration in gases other than N2 (Must be inert) (Requires Quality Plan)

Flow Calibration Reports Common Sections Order Summary IUT Summary ( Instrument Under Test) IUT Condition Environmental Conditions Standard Conditions Reference Standard Documentation Test Data

Calibration Report: HFC-202 By Request

Published Accuracy & The GCF GCF – Gas Correction Factor

Calibration Report: Test Data Recorded Measurements Reference Flow Temperature Mass Flow DUT (Device Under Test): Indicated flow Output VDC Flow in SLM Estimated Uncertainty % FS and % PT

Calibration Report: HFC-D-302

Calibration Report: HFM-200 LFE

Combined Test Report Working Pressure Oxygen Clean

Calibration Report: HFM-201

Valve Check Test Report All two stage valves ( 203/303/307) Automated Test

Other Industry Terms

Turn Down Ratio: ratio of maximum flow to minimum flow at a stated accuracy Rangeability: how much the range can be adjusted without major modifications Zero Drift (offset error): how far from zero an instrument will change Span Drift (span error): shift in the slope of the calibration curve

Other Industry Terms Transducer Sensor Gauge Meter -Vacuum: Electronics and display -Flow: bypass, sensor, electronics

Other Industry Terms Controller Flow meter with a solenoid valve or Set Point Relays Power Supply – unit that converts AC “wall” current to DC “electronic circuit” current Digital: microprocessor on board

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