HOW OFTEN SHOULD YOU CALIBRATE?
IMPROVE LOOP CALIBRATIONS
Significant performance improvement can realized by optimizing the loop calibration measurement system to better accommodate the unique characteristics of the temperature sensing element. This four-page PDF walks you through the necessary steps to get the most from your temperature sensing equipment. The direct link is at http://tinyurl.com/k4lv7f6.
MAINTAINING YOUR pH SENSORS
All pH readings are supposed to be taken and accepted only when the pH sensor is clean, so one must make sure the sensor is clean before doing a calibration. Once a pH sensor is installed in the process and operating, how do you determine when it is time to take the sensor out of the process, and do a cleaning or calibration? Does one perform both a cleaning and a calibration or just a cleaning, or just a calibration? This paper will address knowing when to do a pH sensor calibration versus a calibration check; how to properly clean a pH sensor; how to perform a pH sensor calibration; and a decision tree for step-by-step guidance. Free and downloadable PDF. The direct link is at http://tinyurl.com/l8rsjdk.
CALIBRATING SMART INSTRUMENTS
In the early days of smart transmitters, the concept of remote range setting ("remote calibration”) and re-ranging without applying input was revolutionary. It took years of education to be accepted and understood. Calibration can be carried out using a handheld communicator in the field, a laptop in the workshop, or from intelligent device management software as part of an asset management solution. Electronic Device Description Language (EDDL) is the technology used by device manufacturers to define how the system shall display the device information and functions to the technician. This document covers how EDDL works with sensor trim, range setting, position feedback sensor trim, device integration and other issues. The direct link to the free PDF is at http://tinyurl.com/9eultke.
This is one of the chapters in NIST's Engineering Statistics Handbook (www.itl.nist.gov/div898/handbook/index.htm), covering a variety of calibration topics, including types of calibration, calibration designs, control of instrument calibration and more. Access is free. The direct link is at http://tinyurl.com/bv2dpnw.
NIST Information Technology Laboratory
This free tutorial covers calibration basics: instrument system models, instrument errors, range, accuracy, repeatability, stability, time-lag error, reliability, drift, proper procedures and calibration errors. Each section contains diagrams, basic equations and self-assessment tests. On completion of this tutorial, you should be able to explain the model of a basic instrument system, calculate the relationship between input and output for a complete system, explain and identify the main errors that occur in instrument systems, explain the basic principles of calibration, and explain primary and secondary standards. The link to the tutorial is www.freestudy.co.uk/instrumentation/tutorial4.pdf.
EBook Browse gives users access to ebooks on a wide variety of subjects. The direct link to a page with a collection of PDFs on calibration subjects is located at http://tinyurl.com/nf6lsxb. Registration is required, but many of the publications are free.