The Problem With Shunts
Author(s): David W. Braudaway
Abstract/Introduction:
An understanding of the properties of resistance materials and the effects of resistor construction is necessary to assure optimum application. Reviewed are the characteristics of precision resistance alloys, laboratory type moderate- to high- precision resistors and the design and construction of resistors and shunts. The effects of resistor termination and terminals are briefly reviewed with emphasis on the requirements necessary to produce four-terminal connections. In use precision laboratory resistors are often adapted to serve as moderate current shunts, and, equally often, are damaged in the process. Shunts are specified with a maximum current but their characteristic has not often been verified by calibration. Use of a 50 mV shunt to produce 100 mV drop raises the temperature to the value where damage results. Precision calibration of the shunt gives a resistance versus temperature characteristic and reduces uncertainty of the values by about two orders of magnitude.
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Document ID:
094D367D
Three Calibration Procedures
Author(s): Stanley Novak
Abstract/Introduction:
This paper concerns the design of three calibration procedures, with a different challenge in each. The first effort (17-20AR-87) has a TI (Test Instrument) available during the writing process. This effort is the adaptation of a methodology used in higher level laboratories, to a lower level laboratory ( FCA or depot laboratories). The second effort (17-20AZ-131) shows the careful choice of methodology and test points to use calibration standards for parameter support to NIST. A complication in the second effort is the lack of a TI during the writing process. The third effort (17-20AZ-128) illustrates the difficulty in supporting a TI that is as accurate as the NCE standards. The third effort is also written without a TI and illuminates the important and necessary contributions of other sources in the procedure development process.
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Document ID:
291CDF2C
U.S. National Standards For High Pressure Natural Gas Flow Measurement
Author(s): Aaron N. Johnson, Bill Johansen
Abstract/Introduction:
NIST plans to establish a calibration service for flow meters used in the custody transfer of high pressure natural gas. These calibrations will provide internationally recognized flow traceability for the U.S. natural gas industry over a flow range from 0.25 m3/s (3.2 104 acfh) to 9 m3/s (1.1 106 acfh) at a nominal pressure of 7500 kPa and at ambient temperatures. Flow meter calibrations will be performed at CEESIs Iowa facility under NISTs metrological control, using working standards that are traceable to NISTs primary flow standards. The measurement uncertainty of these calibrations range from 0.25 % to 0.27 % (with a 95 % confidence level) depending on flow rate. This manuscript documents the five-stage scale-up process used to establish traceability between NISTs low-pressure, air-flow primary standard to flowmeters calibrated at CEESIs Iowa facility in natural gas at up to 54 times the volumetric flow and 10 times the pressure.
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Document ID:
16516CB1
Development Of A 500 Slm High Speed Piston Prover
Author(s): Harvey Padden
Abstract/Introduction:
Piston provers have traditionally been used for flows below approximately 50 slm. Above that level, bell provers, which are much slower and less convenient to operate, have been used. We sought to experimentally establish the feasibility of very high-speed benchtop viscoussealed piston provers for flows up to 500 slm. The difficulties to be overcome in building a prototype included: Constructing a 152 mm by 600 mm piston-cylinder pair with a clearance of approximately 25 microns along the full stroke Procuring valves with low enough restriction (Cv) to allow gravity reset Detecting piston position optically Accounting for effects of the pistons low resonant frequency and other dynamic effects We constructed such a prover and conducted numerous experiments to characterize the internal pressure (hence, piston motion) characteristics during the cycle. The prototype was then tested at NIST against sonic nozzles over a flow range of 10 slm to 500 slm. The prover exhibited linearity agreement to approximately 0.04%, with 0.05% or better reproducibility in a second run. Based upon these data and upon further uncertainty analyses, we have begun commercial production of very high speed 500 slm benchtop provers. We believe that our resulting laboratory master provers, after further characterization, will have a combined standard uncertainty of better than 0.1% and a dynamic range of 5 to 500 slm. The commercial provers will be offered at somewhat higher uncertainty, perhaps 0.2%.
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Document ID:
C1E0211D
Uncertainty Of NIST Airspeed Calibrations
Author(s): T. T. Yeh, J. m. Hall
Abstract/Introduction:
The National Institute of Standards and Technology (NIST) provides calibration services for airspeed instruments. Here, we describe NISTs recently upgraded airspeed calibration system and its uncertainty. At NIST, airspeed calibrations are performed over the range 0.15 m/s to 40 m/s in the wind tunnel that has a test cross section of 1.5 m by 2.1 m. The standard for airspeed measurement is a fiber optic laser Doppler anemometer (LDA), which is calibrated with known velocities produced by a rotating disk. The expanded airspeed uncertainty at 95 % confidence level (i.e. coverage factor k2) in m/s is the root-sum-square of 0.0064V and 0.0036 m/s, where V is airspeed in m/s. This gives a maximum uncertainty of 2.5 % (0.0038 m/s) at the lowest airspeed of 0.15 m/s and a minimum uncertainty of 0.65 % (0.26 m/s) at the highest speed of 40 m/s.
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Document ID:
4174E5DE
Development Of A Web-Based Pressure Sensor Calibration Test Bed
Author(s): Xiaoping Yun, Charles K. Le, Harold Glick, Randy Rupnow, James Calusdian
Abstract/Introduction:
The design, development, and demonstration of a web-based automated pressure sensor calibration test bed system are presented in this paper. The objective of the test bed is to showcase a virtual ship prototype with various network-capable pressure sensors and to validate the feasibility of remotely calibrating pressure sensors using the World Wide Web. The test bed includes four types of pressure sensors: a Honeywell digital pressure sensor with RS-232 output, an Omega analog pressure sensor, a Power-over-Ethernet (PoE) pressure sensor from ISI, and a custom-made ZigBee-based wireless pressure sensor. All sensors are ultimately connected to a TCP/IP network. The test bed allows remote and automated calibration of these pressure sensors through a web browser. The user selects a target pressure sensor to be calibrated from a graphic user interface (GUI), which leads to another GUI embedded with a Java Applet, displaying the realtime pressure readings as well as the current calibration constants. One click on a button initiates an automated process of applying pressure to the target sensor at the pre-determined pressure values, recording the readings from the target sensor and the calibration standard, and calculating the new calibration constants. The operation of the test bed has been successfully tested and evaluated locally and remotely.
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Document ID:
AF09154A
Sensor Calibration For The Next Navy And The Navy After Next
Author(s): Harold Glick, Randall Rupnow
Abstract/Introduction:
For the current and future Navies calibration is becoming an increasing burdon that runs counter to the Navys intent to reduce the shipboard workload. However, increased ship sensorization is seen as the solution to monitoring of shipboard functions and to providing the accurate data needed to support the mathematical algorithms for condition based maintenanace and prognostic health maintenanace. This paper will present the background issues to the new calibration methods being developed or proposed that will reduce the sensor calibration requirements to manageable or miniscule levels. (The other papers in this session will present the technical approaches in more detail.)
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Document ID:
47B277F3
Correlation Of Thermographic Assessment Of Vascular Reactions With Bmi, Heart Rate, And Stress
Author(s): Shay Edwards
Abstract/Introduction:
The objective of this study is to expand on previous findings by evaluating if there is a correlation with thermographic assessment of vascular reactions among three distinct groups of participants using Body Mass Index (BMI), heart rate and stress.
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Document ID:
5C479BAB
RF/MICROWAVE Coaxial Connector Care
Author(s): Greg Miller
Abstract/Introduction:
An RF/Microwave measurement is only as good as the connections in that measurement. Cleanliness and careful handling of RF/Microwave coaxial connectors are critical for making repeatable and accurate measurements. This paper will focus on the Type-N connector which is still the most common connector being used. Care and handling of cables, adapters, attenuators, and other passive devices, as well as standards such as signal generators and spectrum analyzers, will be discussed in this paper. Measurement data will be presented. Also discussed will be connector components and their critical dimensions.
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Document ID:
351F8A1D
Rf And Microwave Connectors
Author(s): Tom Kawabata
Abstract/Introduction:
Ambiguity may exist in understanding the proper usage of RF, Microwave and Millimeter-Wave connectors for a novice and as well for the well-seasoned metrologist. The purpose of this presentation to unravel and examine the mystery of the most popular connectors used in RF, Microwave and Millimeter-Wave Metrology. We will take a look at the Type N, SMA, 2.35mm, K, 2.4mm, 1.85mm (V) and 1mm connectors. We will study the construction of each type of connector, the characteristics of each connector, the application for each type of connector and the care required for each type of connector. Lastly, we will look into what is in store in the future for RF, Microwave and Millimeter-Wave connectors.
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Document ID:
D729395F
Measuring Output Vswr For An Active Levelled Source
Author(s): Paul Roberts
Abstract/Introduction:
Mismatch error is one of the major contributions to measurement uncertainty in RF & Microwave calibration. When a signal source is used in calibration applications, knowledge of the output impedance (or source VSWR) is necessary to enable users to estimate the mismatch uncertainty contribution when performing their measurement uncertainty calculations. However, measuring the output match of an active levelled source can be difficult. The measurement techniques generally used for passive components cannot be used for active levelled sources. If those methods are used, they are likely to give erroneous misleading results. This paper discusses the output VSWR measurement method chosen for use in manufacturing test and calibrations systems for a new RF & Microwave source instrument. It also describes the steps taken to validate results by comparisons with other methods less well-suited for automation and production line usage.
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Document ID:
3BD4ABFC
A Primary Calibration System For The Support Of High Performance Gas Flow Transfer Standards
Author(s): Michael Bair, Casey Rombouts
Abstract/Introduction:
The practical application of high performance gas flow transfer standards requires means to efficiently and reliably calibrate them with very low measurement uncertainty. A unique primary gas flow calibration system has been developed to support gas flow transfer standards based on laminar flow and sonic nozzle based elements in the range of 2 x 10-5 gs-1 (1 Ncc min-1) to 50 gs-1 (2500 Nlmin-1). The primary calibration system is made up a gravimetric standard up to 0.2 gs-1 (10 Nl min-1) and a group of sonic nozzle based flow elements to extend the gravimetric reference flow measurements to higher values. Any non-corrosive gas can be studied. The gravimetric system measures depleted gas mass real time using a force balanced load cell and an automated taring system to eliminate force measurement drift over time. The group of nozzles uses the extensive nature of flow and a successive addition technique to build up the gravimetric reference measurements to higher flows. The primary calibration system supports a calibration chain made up of a group of laminar flow and sonic nozzle based elements characterized with a variety of gases. The structure of the group allows verification of the coherence of flow measurements up and down the chain and the precision of the chain to be quantified and maintained over time. The calibration chain is used for day to day calibration of gas flow transfer standards. A complete uncertainty analysis for the primary gravimetric system and the calibration chain has been performed.
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Document ID:
837D8884
Thermal Mass Flow Sensor Similarity Theory - Comparison With Experiments
Author(s): Chiun Wang
Abstract/Introduction:
A similarity theory was previously proposed for the thermal mass flow sensor to describe the nonlinear relationship among the sensor output, the gas flow rate, and the gas thermal-physical properties. In a compact form, the theory expresses the ratio of the sensor output to the gas thermal conductivity, S/k, as a function of the Peclet number of the flow in the sensor tube in a compact form. In the present paper, the similarity theory is further compared against experimental data collected from various semi-conductor process gases using mass flow controllers equipped with constant-temperature capillary thermal mass flow sensors. The similarity theory was primarily confirmed by scaling the live-gas data using gas thermal-physical property constants listed in common physics and chemistry handbooks. Minor discrepancies between the experimental data and the theory are associated with: (1) the simplifying approximations made in deriving the heat transfer mathematical theory leading to the similarity model and (2) uncertainties in the gas thermal-physical property constants used for the data analysis. For practical applications these discrepancies were compensated by adjusting the gas specific-heat and thermal-conductivity coefficients by using two multiplying constants, ec and ek respectively, until the theory and the data match to within tight tolerances. Among the 20 or so semi-conductor process gases tested, the established multiplying constants are all fairly close to 1, suggesting that the current thermal-mass flow sensor theory is sound. Although the original similarity theory was developed for the constant-temperature thermal mass flow sensors, an argument is provided to show that the theory might also be used to explain the operation of a constant-current thermal mass flow sensor and its gas conversion factors.
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Document ID:
09380DF6
Determining Size Of Source For Handheld Infrared Thermometers - Theory And Practice
Author(s): Frank Liebmann
Abstract/Introduction:
Infrared (IR) thermometry is a very useful form of temperature measurement. It has advantages over contact thermometry. These advantages typically include a quicker response time and not having to interfere with the system being measured. However, it is typically not as accurate as contact thermometry. Part of the difference in accuracy is due to the fact that IR thermometers themselves are not as accurate as contact thermometers. The other part of the difference can be due to the user not controlling factors which can cause greater uncertainty of measurement. Major uncertainties in IR thermometry can be a result of emissivity, repeatability and size of source effect (SSE). Size of source (sometimes referred to as spot size) can be especially difficult because information on size of source is difficult to find. This paper discusses size of source as it applies to IR thermometers. It covers experimentation done on handheld IR thermometers to determine size of source using accepted practices. It also compares this data to manufactures specifications given with the tested instruments. It demonstrates how to apply this knowledge to account for the uncertainty caused by not having a source of proper size and shows how to apply this data to an uncertainty budget.
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Document ID:
C4F9BD2B
Comparison Between Melting And Freezing Points Of Aluminum And Silver
Author(s): R. Ding, M.J. Zhao, D. Cabana, D. m. Chen
Abstract/Introduction:
For metal fixed point cells, it will be convenient if the melting points can be used instead of the freezing points in calibration of standard platinum resistance thermometers (SPRTs) because of easier realization and longer plateau duration of melting plateaus. Experimental research was carried out to compare the melting and freezing points of aluminum and silver by using the inter-comparison method with SPRTs. The influence of the furnace maintenance temperature on the performance of melting and freezing plateaus were investigated and discussed. Differences in results between the melting points and the freezing points are shown. Uncertainty budget analysis of the melting points and freezing points is presented. The experimental results show that it is possible to replace the freezing point with the melting point of aluminum cell in the calibration of SPRTs in secondary-level laboratories if the optimal methods of realization of melting points are used.
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Document ID:
22BBA775
Through The Wall Temperature Measurement Effects In Simple Systems
Author(s): Thomas O. Maginnis
Abstract/Introduction:
A situation that frequently occurs in temperature measurement applications is the need to infer the temperature of one material medium using a temperature sensor attached to an adjacent material medium. For example, one may try to measure the temperature of a corrosive hot fluid using a temperature sensor attached to the outside of the fluid container wall. In a more fundamental sense, one may regard the temperature sensor itself as one material medium, and the sample system whose temperature is to be measured as the second medium. Two physical effects come into play in such situations: the difference in resolution for temperature changes in the two media arising from the heat capacity ratio of the materials and the settling time required for a uniform temperature to be established across both media when they start out at different temperatures. Fortunately, for stationary media, this heat exchange problem can be completely solved for simple geometries in terms of the thermal properties of the two material media and their geometrical dimensions. The solutions enable both the settling time constants and the temperature leverage ratios to be calculated and predicted. Solutions and example illustrations will be provided for simple two-layer systems in planar, cylindrical, and spherical geometries, for the simplest case where the outer surfaces of the two-layer system are thermally insulated, but the internal bounding surfaces are in good thermal contact. These solutions are useful for understanding how closely the measured temperature of the outer layer represents the true temperature of the inner layer in such situations, and for estimating the uncertainty of through the wall temperature measurements.
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Document ID:
94A928CC
Study On Calibration Technique Of High Impact Acceleration Sensors
Author(s): Jing Zu, Zusen Lin, Jinbiao Fan, Peng Xu, Xiangnan Shen
Abstract/Introduction:
The paper presents a new idea for calibration technique of high impact accelerometers in range of 10000200000g. For tracing calibration of sensors, a Hopkinson bar is excited with a wide impact pulse bigger than 100ys in width produced with a projectile of an air-gun , and the movement of the install base of the sensor calibrated is measured by a laser differential velocity interferometer at the same time. The output signal of the interferometer is used as the source to calibrate the sensitivity of the sensor. The width of exciting pulse must be wide enough, and the highest frequency component is much lower than the natural vibration frequency of the sensor calibrated, to avoid the effect of natural vibration of the sensor. Dynamic calibration of sensors refers to an idea to obtain the frequency response characteristic of the sensor in frequency domain. The process of dynamic calibration of a high impact accelerometer is also used with a Hopkinson bar, but excited with a narrow impact pulse with which the higher frequency component can excite the natural vibration of the sensor calibrated. For sensors with natural vibration frequency greater than 200kHz, an explosion of explosives is used to generate an excite pulse of 23ys in width as the excite source of the sensor. Similarly, the movement of the setting end-plane of the sensor calibrated is measured by a strain gauge on the Hopkinson bar. Then comparing with the frequency characteristics of both the sensor calibrated and the exciting source, the frequency response characteristic of the sensor should be obtained. Based on the things mentioned above, the principle of dynamic calibration of high impact accelerometer and the process of calibration are discussed respectively. The the method of data processing is further analysized. Keywords - High impact, Acceleration sensor, Dynamic calibration, Tracing calibration, Hopkinson bar, Excitation pulse width, Thickness of install base, Diameter of the Hopkinson bar.
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Document ID:
C7E039EA
Uncertainty Analysis Of Measurement Systems Used For Air Shock Wave Pressure
Author(s): Zhijie Zhang, Daihua Wang, Wenlian Wang, Hongmian Du
Abstract/Introduction:
The measurement of air shock wave pressure is a typical problem of dynamic measurement. Because the measurement data in many cases is used to judge the quality of a product, or as a basis for changes being made during a development phase, uncertainty analysis or assessment of measurement data takes a very important role in the process of reporting experimental results. It is very difficult or impossible for most of dynamic or transient measurements to be experimented repeatedly under the same condition, so their uncertainty analysis differs from the method of analyzing static measurement data. The paper gives several main components of uncertainty and their experimental data of the measurement system of air shock wave pressure, especially analyses and processes dynamic sensitivity and overshoot values of the system excited by step pressure signal which is generated by shock tube. The results of uncertainty analysis Type B are presented. The method of dynamic uncertainty helps to the solution to analyze and assess the result of single measurement or a few measurements.
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Document ID:
F98D6882
Compensation Of Dynamic Measurement Error For Transient Surface Temperature Sensors
Author(s): Hanchang Zhou, Xianwen Meng
Abstract/Introduction:
To improve the temperature sensors dynamic characteristics the dynamic compensation based on the dynamic calibration results for temperature sensors is reported. The dynamic modeling and measurement errors compensation are described. The model of temperature measurement system is constructed with the system identification and the validity of this model is testified by the cross-validation method. Using inverse filter method the dynamic characteristics of temperature measurement system are compensated: the dynamic error is reduced and the work bandwidth widened evidently. The method is proved to be effective by the experimental results that the transient temperature is measured by a K type butt-welded bare wire thermocouple.
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Document ID:
9F1A0FB9
Measurement Risk Analysis Definitions As Applied To Z540.3
Author(s): Del Caldwell, Dennis Jackson
Abstract/Introduction:
Measurement decision risk analysis provides a probability description of the possible results of a calibration scenario. Under a basic calibration testing scenario, the measurement from a Calibration Standard (CAL) is compared with the measurement from a Unit Under Test (UUT). If the difference between these measurements is greater than some required tolerance, the UUT is declared to be out of tolerance (OOT). The usual result of this OOT declaration is that the UUT is adjusted in some fashion so that the tested measurement is no longer OOT. Since the CAL makes measurements with some error, there is a probability that the decisions made through this testing process could be incorrect. The problem is trying to define the exact nature of these incorrect decisions in unmistakable terms. Typically, these incorrect decisions are described as false accept (incorrectly accepting an OOT UUT measurement) and false reject (incorrectly rejecting an in tolerance UUT measurement). This paper will focus on the false or incorrect acceptance decision aspect of measurement decision risk. This paper lays out the error mathematics describing representative measurement models applied to calibration scenarios. Using these error mathematics, the meaning of a false accept decision event is unambiguously described. Further, the probability of such events or probability of false accept decisions (PFA) can then be simply defined as the probability of such an event. The probability mathematics for calculating the PFA is shown. These probability equations do not require the assumption of specific probability distributions, such as the Normal (or Gaussian) distribution. However, as an example, this paper also provides the specific equations needed to calculate the PFA using the usual Normal distribution assumptions. Four methods for meeting PFA requirements are discussed. These methods are based on exact and conservative methods to estimate PFA for a calibration scenario, and exact and conservative methods to adjust the calibration scenario using guard bands.
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Document ID:
C48C7E85
Measurement Risk Analysis Definitions As Applied To Z540.3
Author(s): Del Caldwell, Dennis Jackson
Abstract/Introduction:
Measurement decision risk analysis provides a probability description of the possible results of a calibration scenario. Under a basic calibration testing scenario, the measurement from a Calibration Standard (CAL) is compared with the measurement from a Unit Under Test (UUT). If the difference between these measurements is greater than some required tolerance, the UUT is declared to be out of tolerance (OOT). The usual result of this OOT declaration is that the UUT is adjusted in some fashion so that the tested measurement is no longer OOT. Since the CAL makes measurements with some error, there is a probability that the decisions made through this testing process could be incorrect. The problem is trying to define the exact nature of these incorrect decisions in unmistakable terms. Typically, these incorrect decisions are described as false accept (incorrectly accepting an OOT UUT measurement) and false reject (incorrectly rejecting an in tolerance UUT measurement). This paper will focus on the false or incorrect acceptance decision aspect of measurement decision risk. This paper lays out the error mathematics describing representative measurement models applied to calibration scenarios. Using these error mathematics, the meaning of a false accept decision event is unambiguously described. Further, the probability of such events or probability of false accept decisions (PFA) can then be simply defined as the probability of such an event. The probability mathematics for calculating the PFA is shown. These probability equations do not require the assumption of specific probability distributions, such as the Normal (or Gaussian) distribution. However, as an example, this paper also provides the specific equations needed to calculate the PFA using the usual Normal distribution assumptions. Four methods for meeting PFA requirements are discussed. These methods are based on exact and conservative methods to estimate PFA for a calibration scenario, and exact and conservative methods to adjust the calibration scenario using guard bands.
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Document ID:
E7DE02E1
Applying Measurement Science To Ensure End Item Performance
Author(s): Howard Castrup
Abstract/Introduction:
A methodology is presented for the cost-effective determination of appropriate measurement assurance standards and practices for the management of calibration and test equipment. The methodology takes an integrated approach in which quality, measurement reliability and costs at each level in a test and calibration support hierarchy are linked to their counterparts at every other level in the hierarchy. This relates requirements and capabilities at any given level in the hierarchy to the performance objectives of the end items which the hierarchy is ultimately employed to support. Included in the methodology is the capability to quantify the effect of calibration/test support on costs resulting from the risk of degraded end item performance, either in terms of losses suffered through poor performance or expenses incurred from returned products, warranty rework or reimbursement, legal damages, or retrofit of product improvements.
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Document ID:
3194F9A4
Measurement Decision Risk - The Importance Of Definitions
Author(s): Scott m. Mimbs
Abstract/Introduction:
One of the more misunderstood areas of metrology is the Test Uncertainty Ratio (TUR) and the Test Accuracy Ratio (TAR). There have been many definitions over the years, but why are these definitions important to a discussion on measurement decision risk? The importance lies in the clarity of communication. Problems can immediately arise in the application (or misapplication) of the definition of these terms. In other words, while it is important to understand the definitions, it is more important to understand concepts behind the definitions and to be precise in how they are applied. The objective of any measurement is a decision. Measurement Decision Risk is a way to look at the quality of a measurement, and although it is not a new concept, it has generated a lot of attention since its addition as a requirement in the new U.S. National Standard, ANSI/NCSL Z540.3-2006. In addition to Measurement Decision Risk as the prime method of managing measurement risk, Z540.3 has added, as a fall-back, an explicit definition for TUR. The impact these new requirements may have on calibration service providers has become the topic of much discussion and in some cases concern. This paper will look at the concepts behind the definitions and how they relate to Measurement Decision Risk. Using common examples, this paper will also provide a comparison of various elements of risk related to measurement science using the concepts of TAR, TUR, accuracy ratios, and Consumer Risk (False Accept Risk). The goal of this paper is to provide a better understanding of their relevance to the measurement decision process.
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Document ID:
D1EE082C
Benefits Of Utilizing Item Unique Identification As A Process Improvement Enabler
Author(s): Jamie Pompa, Craig Macdougall
Abstract/Introduction:
The Item Unique Identification (IUID) requirement mandated by the Under Secretary of Defense for Acquisition, Technology, and Logistics (USD AT&L) provides a gateway to reevaluate current business processes and identify process improvement opportunities. In the world of measurement and calibration, the foundation of traceability, accountability, and high quality data established by IUID policies provides multiple opportunities for cost avoidance, improving availability, and extending equipment performance. Cost avoidance stems from faster cycle time, principally from shipping/receiving improvements and reduced lab time lower error rates allowing a reduction in labor to find and correct data errors, as well as labor to identify and quarantine unrecoverable errors within data analyses and avoiding unnecessary procurements due to less work in progress and fewer lost/misplaced items. Improved availability results largely from improved data quality. The enhanced data quality enables more accurate data analysis and tighter confidence intervals, which can lead to calibration interval extensions, reducing the work in progress. Equipment performance extension is a result of the ability to identify poor performers, including equipment, calibrators, procedures, and vendors. Once identified, corrective and/or proactive measures may be taken to resolve poor performance problems and extend the service life of the equipment.
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Document ID:
4E922960
Designing Performance Measures For Calibration And Technical Laboratories
Author(s): Rick Rios, John Brandon
Abstract/Introduction:
Calibration and technical laboratories are under increasing pressure to deliver more with less, to provide enhanced services with flat or diminished budgets. In order to meet this challenge, lab managers need to think of their organizations as independent business units concerned with satisfying their customers, controlling costs, maintaining technical excellence and attracting and retaining valuable employees. To effectively manage their labs, managers need to implement properly designed and adequately balanced performance measures. This paper will present a Process-focused Performance Measurement Model and several helpful tools that managers can employ to improve their organizational performance measures. It will also challenge the Calibration Laboratory Manager to consider whether his/her calibration lab is doing all it should to contribute to the larger organizations success.
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Document ID:
73D8974C
Maintaining In-Situ Traceability On The Factory Floor With Process Metrology
Author(s): Nicholas Mason
Abstract/Introduction:
In the mid 1990s, Fluke proposed a method for maintaining factory test systems without requiring the traditional periodic recall of each reference in the system 1. This method, called Process Metrology is a means to establish traceable calibration of factory test systems on the factory floor. Process Metrology was born out of the need to calibrate high accuracy calibrators on the factory floor without having to stop production for factory station maintenance and minimize the need for spare, high cost test equipment. At that time, it was unclear whether Process Metrology was cost effective and would meet its goals 1,3. Process Metrology has met its goals. It has also provided benefits that were not obvious at the beginning and is standard practice on many production lines. This paper reviews and discusses the current state of Process Metrology at Fluke. Examples from a new 6.5 digit meter are used.
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Document ID:
0B3A9900
Re-Definition Of The Kilogram: Current Status And Impact On Mass Metrology
Author(s): Zeina J. Jabbour
Abstract/Introduction:
A redefinition to replace the last remaining artifact -based SI unit is proposed for 2011. This paper presents a short summary of the status of current international efforts focused on the redefinition, internationally agreed upon requirements for the redefinition, current positions and activities of international committees, process of redefining a SI unit, possible mechanisms for the dissemination of the new SI Kilogram, and the impact of the redefinition on practical mass metrology.
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Document ID:
904DB5A3
Proficiency Testing In U.S. State Weights And Measures Laboratories
Author(s): Elizabeth J. Gentry, Georgia L. Harris, Val R. Miller
Abstract/Introduction:
The National Institute of Standards and Technology (NIST) Weights and Measures Division (WMD) manages a program for State Weights and Measures laboratories that includes: 1) laboratory Recognition following ISO/IEC 17025:2005 1, 6 and sponsorship of Accreditation through the National Voluntary Laboratory Accreditation Program (NVLAP) 2) hands-on training at NIST and training through regional measurement assurance programs (RMAPs) and 3) a formal Proficiency Testing and Interlaboratory Comparison (PT/ILC) program. The objective for this WMD effort is to ensure nationally consistent measurement results and the acceptance of State laboratory measurements. This paper presents key features of the PT/ILC Program: measures of success collaboration challenges the use of template tools and efforts regarding continual improvement.
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Document ID:
991381EB
Metrology Infrastructure In China
Author(s): Yuning Duan, Xiaoxun Gao
Abstract/Introduction:
This presentation firstly gives a brief introduction about Chinas metrology infrastructure main topics covered are the administrative system, the legal system, the technical system, and the traceability system. Besides, additional introduction was given to the National Institute of Metrology (NIM), China, a key element in Chinas metrology system that plays a very unique and pivotal role in facilitating the countrys international trade and promoting the building of a more harmonious society. NIMs mission, function, R&D programs and its second experimental base are introduced.
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Document ID:
19CAF71F
China-Us Collaborations In Electrical Metrology: Nist-Nim Interactions
Author(s): William E. Anderson, Barbara L. Goldstein
Abstract/Introduction:
This paper discusses an historic cooperative arrangement between the national metrology institutes of China and the United States to collaborate on electrical metrology, and the anticipated impact of this arrangement.
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Document ID:
380BDCF6
Calibration Service For Vector Network Analyzers In China
Author(s): Liu Xinmeng, Huang Hui, Zhang Jian
Abstract/Introduction:
The status of calibration service for vector network analyzers (VNAs) in China is introduced. Three kinds of calibration guidelines of network analyzers are compared one of them is being constituted by NIM to provide an efficient and cost-effective service for VNAs to trace metrological standard.
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Document ID:
93BFBD9B
China-Us Collaborations In Electrical Metrology: Nist-Nim Interactions
Author(s): William E. Anderson, Barbara L. Goldstein
Abstract/Introduction:
This paper discusses an historic cooperative arrangement between the national metrology institutes of China and the United States to collaborate on electrical metrology, and the anticipated impact of this arrangement.
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Document ID:
3B787F28
Piezoresistive Chemical Sensors Based On Polymer Thin Films
Author(s): G. Gerlach, m. Guenther, J. Sorber, Z. Shi
Abstract/Introduction:
For several decades piezoresistive sensors had been one of the most important driving factors for the development of MEMS technology. Piezoresistive pressure sensors have still a MEMS market share of some 20 % and an annual growth rate of about 6.6 %. Already 20 years ago we proposed the usage of piezoresistive sensors for other measurands than just mechanical ones. Adding functionalised polymer coating which shows swelling due to other physical or chemical values leads to a similar deflection of the thin silicon bending plate like for pressure sensors. The present paper covers two applications: a) thin films of polyimide for humidity and gas sensors, and b) the hydrogel layers for the measurement of concentrations of particular chemical species in aqueous solutions.
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Document ID:
BCE6A015
Electronic Noses And Artificial Olfaction
Author(s): Jan Mitrovics, Frank Rck And Udo Weimar
Abstract/Introduction:
Electronic noses have been a research topic for more than 25 years1 with commercial instruments being released in the early 1990s. Despite this long history and the considerable research and development efforts an artificial instrument that objectively measures odors as perceived by a human is still a dream.
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Document ID:
3067F247
A Vapor Generator Based Calibration System For Use As An Interim Standard For The Joint Chemical Agent Detector
Author(s): Christopher H. Clark, Mary m. Graupmann, Michael L. Bishop
Abstract/Introduction:
A system has been designed, constructed, and is in the process of being tested to provide a known concentration of chemical warfare agent (CWA) simulant to a Joint Chemical Agent Detector (JCAD). JCAD is a hand held ion mobility spectrometer that alerts a soldier to the presence of a CWA. The current JCAD iteration is commercially available from Smiths Detection under its trade name Light-weight Chemical Detector (LCD) 3.2E. Although the detector is not considered quantitative, it alarms at a threshold value and this value requires calibration. The system here uses a Kin-tek vapor generator in conjunction with a 10-port valve and Agilent 7890/5975 gas chromatograph-mass spectrometer (GC/MS) to assure the concentration delivered to the JCAD is precise and accurate. In practice this system would serve as a depot-level standard to be calibrated by NIST once a high-level chemical simulant standard exists. Current work has focused on integrating the 10-port valve, GC/MS, and vapor generator, assuring they work in concert to produce accurate and precise concentrations.
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Document ID:
AA05CB8B
Trapezoidal And Triangular Distributions For Type B Evaluation Of Standard Uncertainty
Author(s): Raghu N Kacker, James F. Lawrence
Abstract/Introduction:
The Guide to the Expression of Uncertainty in Measurement (GUM), published by the International Organization for Standardization (ISO), recognizes Type B state-ofknowledge probability distributions specified by scientific judgment as valid means to quantify uncertainty. The ISO-GUM discusses symmetric probability distributions only. Sometimes an asymmetric distribution is needed. We describe a trapezoidal distribution which may be asymmetric depending on the settings of its parameters. We describe the probability density function (pdf), cumulative distribution function (cdf), inverse function of the cdf, moment generating function (mgf), moments about origin (zero), expected value, and variance of a trapezoidal distribution. We show that triangular and rectangular distributions are special cases of the trapezoidal distribution. Then we derive the moment generating functions, moments, expected values, and variances of various special cases of the trapezoidal distribution. Finally, we illustrate through a real life example how a Type B asymmetric trapezoidal distribution may be useful in quantifying a correction for bias (systematic error) in a result of measurement and in quantifying the standard uncertainty associated with the correction. An essentially identical version of this paper appeared in Metrologia, 44 (2007) 117-127. This is work of US federal government employees and hence not subject to copyright. Any references to commercial products in this document do not imply endorsement by the US National Institute of Standards and Technology.
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Document ID:
5A3C5B07
How To Build Your Own Bilateral Consumer Risk Calculation Tool, Accounting For Product And Measurement System Biases
Author(s): Ricardo A. Nicholas
Abstract/Introduction:
Specifics are provided to enable anyone with Microsoft Excel to develop their own computer application program to easily and quickly calculate bilateral consumer risk for any realizable combination of parameters, also taking into account the biases of the measurement system and unit under test. These biases are commonly encountered, but are currently only able to be treated in a very small number of costly not-easy-to-use commercial mathematical software programs. The affect of these biases on consumer risk should be quantified, since they can result in an actual risk of 60% in some cases when risks have been otherwise estimated to be less than 1%. It is also conversely true that the actual risk can be miniscule when they have been otherwise estimated to be as large as 60%. Your own bilateral consumer risk calculation tool will enable you to estimate the actual risk, thereby avoiding overly restrictive or overly liberal measurement consequences. Theory and application guidance, as well as all actual cell formulas expressed in both Excel and basic mathematical forms are provided. The principles of this method and first-generation copies of the Excel worksheets have previously been presented by this author and published in the MSC proceedings of 1999 entitled, Measurement Decision Risk Simplified.
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Document ID:
31B948AB
On Line Training For Metrology
Author(s): Paul R. Selzer, Jack Somppi
Abstract/Introduction:
[Abstract Not Available]
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Document ID:
491D2FEB
Volumetric Positioning Error Measurement At Various Thermal Conditions
Author(s): Charles Wang
Abstract/Introduction:
To manufacture accurate parts, the volumetric position accuracy of the machine tool is very import. Reported here are the basic theory of 3D volumetric positioning errors and description of the laser vector technique.
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Document ID:
59673841
Electrical Safety Testing In Calibration Laboratories
Author(s): Peter Jager
Abstract/Introduction:
Wherever electric or electronic devices of any kind are in use, there is a calculable chance for electric shocks or accidents. Electrical shock can be caused by a variety of reasons: defective powercords, dirt obstructed / logged fan grids, replaced fuses with incorrect ratings, defective components e.g. . For that reason, in Germany any equipment located in all public accessible places - like in stores, malls and of course in working areas too, must be checked and tested for electrical safety. Devices, that usually stay in place like lamps or coffeemakers for instance, are tested in long intervals - devices that easily wear out, like transportable instruments, extension cords or similar devices need to be checked more often. What is necessary in public places is much more important for calibration laboratories: The technician usually doesnt know anything about the customers use of the equipment turned in for calibration - so a first test must be made to protect him. When his calibration job is finished, he has to ensure that the instrument meets the manufacturers specifications before it is given back to the owner - not only on calibration concerns but for customers safety too. This presentation will give an overview of the mandatory testing regulations and will point out in detail the necessary 3 steps to check and measure electrical safety. It will show and explain a diagram of basic testing and might be a base to set up a procedure for calibration laboratories.
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Document ID:
C15964B9
Development Of Procedure To Determine Measurement Uncertainty Fof Capacity Test For Manual Gas Valves
Author(s): Robert B. Deremer
Abstract/Introduction:
CSA International is an independent, third party testing laboratory specializing in safety and performance testing of consumer products. The tests on gas appliances are contained in nationally-recognized standards that are developed under ANSI procedures. Each appliance standard contains requirements that all of the gas control devices used on the appliance comply with applicable gas control device standards. Virtually all of the gas control device standards contain a test to measure the gas flow capacity of the control. The information from the capacity test is used by the gas control manufacturer to establish ratings for the control, and also by the appliance manufacturers to allow them to properly size the control to the appliance design. The capacity test consists of the measurement of numerous parameters, and the combination of the results of these measurements into a prescribed equation to determine the flow capacity of the gas control. There is an uncertainty associated with each of the measured values, which must be evaluated in order to evaluate the overall measurement uncertainty in the calculated gas control capacity. This paper serves as a good illustration on how to combine the measurement uncertainty results from numerous single discreet measurements to obtain the measurement uncertainty in a result calculated from the discreet measurements. An analysis on the development of sensitivity coefficients is included.
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Document ID:
23592610
Calibration Over Adjustment And The Deming Funnel Experiment
Author(s): Dilip A. Shah
Abstract/Introduction:
When a measurement system is calibrated, there is a tendency to adjust so that it measures the nominal whether the system is measuring within tolerance or not. Is this causing more harm than good? Is the extra adjustment effort worth the time and resources? The Deming funnel experiment is a mechanical representation of many real world processes in industry. This presentation compares the over adjustment practice with Demings funnel experiment illustration.
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Document ID:
0579FCEC
A Quality Calibration System
Author(s): Jay L. Bucher
Abstract/Introduction:
Whether a company is trying for registration to ISO 9000 standards, or accreditation to ISO 17025, or pushing to meet the Quality System Regulation (FDA) - they will need to have a calibration system of some sort, and it is just as easy to implement a quality system as opposed to a non-quality system. But what is a quality calibration system? The basic premise and foundation of a good quality calibration system is to Say what you do, do what you say, record what you did, check the results, and act on the difference. Within this quality system are the basics for any calibration or metrology function: calibration procedures, traceability, uncertainty, calibration records, environmental controls, out-of-tolerance procedures, etc. How much importance is placed on each of these areas is usually determined by who your customer is, and what requirements, standards, or guidelines your calibration program must meet. To this end, a quality calibration system in its basic form can set the foundation for your policies and procedures. The basics, what needs to be addresses and covered, along with a laundry list of other subjects will be presented. This paper will show how a quality calibration system within a company can be a cost effective program while meeting and/or exceeding any compliance or FDA requirements. Other companies have been doing business this way for yearsisnt it about time for everyone to be on a level playing field? You can do it, we can show you how.
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Document ID:
488B3A90
A Measurement System For Spring Parameters
Author(s): Liu Yong, Zhang Saifei
Abstract/Introduction:
Columned helix compression spring is a wide used mechanical part in modern industry, but the conventional examining method has some limitations. The measurement system examine the state of springs by measuring three parameters: free height, maximum height of operating load and the height of maximum examination dead load. According to the parameters, it judges the spring eligibility or not.
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Document ID:
5EBDDFA3
Calibration And Traceability Challenges In Eastern Europe
Author(s): Mladen Jakovcic, Vinja Galjevic
Abstract/Introduction:
This paper examines the development of the metrology infrastructure of a typical small or newly developing European country and the factors which have influenced that development. In terms of metrology, all countries have equal aspirations perhaps the most important is to provide metrology support to its industry whereby ensuring the traceability of results and enabling competitiveness on the international market. In this paper the experiences of the Republic of Croatia will be used to illustrate the situation. Establishing a metrology infrastructure anywhere is an expensive project, but to do it in a small country which - due to the impact of political changes and the disintegration of the former state - is starting from the beginning, is a major technical, political and economic challenge. It is the intent of the Republic of Croatia to become an EU member in order to equally participate in the common European and other markets. To accomplish this it is necessary to institute the appropriate technical infrastructure as well as to apply the already existing confidence building measures. Changes in metrology have for sure been influenced by international pressure to lower technical barrier to trade, primarily via harmonizing technical regulations and decreasing the metrological scope regulated by law.
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Document ID:
419E2E2B
Metrology Challenges In Egypt, Overview And Progress
Author(s): Mamdouh Halawa
Abstract/Introduction:
In modern society, metrology is a hidden infrastructure, that affects most human activities. The national measurement system of Egypt instituted 3000 years B.C. and re-instituted in the first decade of the twentieth-century to take its formal modern shape when National Institute for Standards (NIS) was established in 1963. This article provides an overview of the recent progress on metrology in Egypt with emphasis, for example, on the electrical metrology. Several domains in which metrology play a vital role in different sectors in Egypt are presented. The article is also subjected to highlight the Egyptian exerted efforts to support the metrologists and developers in Egypt to face the global needs in that domain. Some of the international projects in electrical metrology, for example, to meet the needs of providing traceable metrology and calibration support for modern industry, are briefly focused here.
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Document ID:
A60D0EEC
Leveraging Audits Across The Enterprise
Author(s): Larry Cohen, Scott Arrants
Abstract/Introduction:
Site audits performed by Customers and/or Third Parties can be stressful as, too often, they are the only opportunities for independent review of, and feedback on, a Quality System. We have created a simple, yet powerful, approach for leveraging internal audits across the enterprise, including multiple and remote sites, so that we are quick to identify and address gaps and to utilize best practices.
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Document ID:
3CBCEC3C