Fluke msc04 free download

File name msc04.pdf

HAVING CONFIDENCE IN SPECIFICATIONS David Deaver Fluke Corporation PO Box 9090 Everett, WA 98206 425-446-6434 [email protected] Abstract: This paper presents some of the unique specification would have to be assigned challenges in creating instrument to each instrument, taking into account its actual specifications from a manufacturer's performance and the operating environment. In perspective and some of the difficulties practice, this is done by many laboratories when using specifications as an estimate of characterizing a standard but is seldom done by uncertainty from a user's perspective. the manufacturer. Despite the difficulties, specifications are the most common means of determining the Manufacturing Yield Targets Type B uncertainty for the standard when making a GUM (Guide to Uncertainty of Though specifications may be stated with a Measurement) compliant uncertainty confidence, typically between 95% and 99.7%, analysis. An explanation is presented for the all the points tested on the production line must practice of providing 95% and 99% be measured within the specification limits confidence specifications, warranting only before the product can be shipped. For a the 99% specifications, and verifying the 99% standard resistor, whose value is specified at a specifications to 95% confidence. 95% confidence level to be within limits centered about the nominal value for the resistor, we THE BASIS OF SPECIFICATIONS could expect to have to re-trim 5% of the standards before they could be shipped. Simply stated, specifications are an implied Specifying a complex instrument at the true 95% contract between a buyer and seller of a piece of confidence level for each point would be a equipment. The seller expects to be paid if the manufacturing disaster. For example, each product performs within its specifications and the Fluke Model 5520A Multiproduct Calibrator is buyer expects to receive an instrument which tested at 552 points on the production line prior lives up to the promises made in the data sheet. to shipment. If each of the points has a 95% Specifications, however, may or may not be a probability of being found in tolerance, there 552 very good representation of the product's actual would only be a 0.95 = 0.00000000051% perfor