Several organizations and publications reference or insist on maintaining a 4:1 Test Uncertainty Ratio (TUR) without understanding the level of risk that they may be subjecting themselves to. The general thought is if the lab performing the calibrations has standards at least four times better then what they are calibrating that everything is good. This paper discusses TUR, PFA Risk, and why the location of the measurement matters. We will discuss two managed risk guard banding methods (5 & 6) found in the ANSI/NCSL Z540.3 Handbook. We will show that a 4:1 TUR is not enough and can result in a 50 % risk.
Morehouse has been performing both ASTM E74 and ISO 376 calibrations for more than fifteen years. We have been calibrating in accordance with the ASTM E74 standard since its introduction in 1974, and performing ISO 376 calibrations since sometime in early 2000. Until recently, we assumed that the rest of the world and force community knew that the standards were completely different and that either standard could not be substituted for another. This paper explains those differences in more detail.
Measurement decision risk as probability that an incorrect decision will result from a measurement. Are you telling your customers instrument passes without considering measurement uncertainty? If taken to court, are your measurement defensible? This paper examines the proper way to make statements of compliance.
Having troubles understanding measurement uncertainty and how to put together a budget? This paper examines all of the components required to put together a full calibration and measurement capability (CMC) reviewed by Accreditation Bodies for your scope. This is a guide to calculating force measurement uncertainties and was published in Cal Lab magazine.
Article written by Henry Zumbrun for Cal lab Magazine 2014.
What you need to know about molecule excitement decline and dual range calibrations. Article from Test Magazine May 2016 issue.
Article in test magazine from Oct-Nov 2015 issue.
This is a one sheet verification proving the software converts the mV/V values properly. The end user must verify they have entered the coefficients correctly
V1.0.0: 2019 version Morehouse software, which uses the coefficients from the calibration report, typically ASTM E74 or ISO 376 report to ensure the mV/V values can be converted to engineering units. Keeping the calibration in mV/V is important as any adjustments are made at the time of calibration by issuing new coefficients. This keeps the cost down and allows the end-user the ability to easily compare the stability from one calibration to another. It also allows adjustments to other engineering units such as N, kN, kgf, & lbf. In addition, the software allows for multiple load cells to be summed together for weighing or other applications where each individual load cell can be monitored as a percentage of the overall applied load. This feature may be useful for calibrating pipe testers, large force machines where several load cells are required or checking the center of gravity. In addition, the software can convert force to mass values such as lb, kg, grams, and ounces which is useful for the calibration of scales.
V1.3.5: Force calibration software for use with Morehouse 4215, HADI, or DSC-USB Indicators. The software uses coefficients from ASTM E74 calibration and displays engineering units as well as capturing data with a remote control device and pausing readings etc.., Reporting section helps with ASTM E4 field calibrations. Must have Morehouse 4215, HADI, or DSC-USB indicator to use this software.
V1.2: This is the universal version for torque calibration which allows for lbf ft and N m coefficients to be entered. PEAK HOLD and new windows 8/10 drivers on this version. Inverse B0 coefficients.
Having problems figuring out all of the requirements to calculate a CMC for force or torque? This excel sheet provides a template to calculate CMC's with explanations of everything required to pass an ISO/IEC 17025 audit.
Spreadsheet to print load tables for Proving Rings
Spreadsheet to print load tables for Load Cells
Calibration load points for Proving Rings used as standards in a Morehouse UCM
Load table generator for Morehouse A and B Coefficients Sheet for Load Cells
Convert LBF to KGF and N for Calibration load points in compression and tension.
Installation instructions for Morehouse software. This software uses the B coefficients from the calibration report and converts the mV/V readings into engineering units. Every time a new certificate is issued, the coefficient files must be changed. This software helps automate the calibration process and is used with the Morehouse 4215, HADI, and DSC indicators.
V1.4.2: This is the universal version which allows for LBF, KGF, N, kN coefficients to be entered. PEAK HOLD and new windows 8/10 drivers on this version. Inverse B0 coefficients.