Combine your knowledge on Temperature Measurement with the experts and the new Rosemount Temperature Handbook

20131002-145243.jpgEmerson’s Michelle Weimert took the workshop members through the Engineer’s Guide to Industrial Temperature Measurement. Her abstract:

Do you have questions on temperature measurements? Combine your knowledge with the Temperature experts to better understand how you can optimize your operations with superior temperature measurements. With the collaboration of multiple customers and by leveraging years of global experience, the Rosemount team in Emerson wrote a comprehensive Temperature Handbook to share industry best practices. Investigate temperature measurements from the technology basics to engineering and maintaining a temperature point in this workshop.

Michelle opened describing the 9 month effort to put the guide together.

The most common temperature measurement questions included how to choose the right sensor technology, right insertion length for thermowell, best way to calculate accuracy, recommended grounding practices, sensor lead wire color standards, how to choose the proper transmitter, and several more.

Michelle showed a video which will soon be made public which described the considerations in selecting RTD versus thermowell technology. See page 71 of the guide for more. Here’s the link to order your free copy of the guide.

On pages 64-67 the guide highlights how to choose the correct thermowell for your application. The Rosemount website at Rosemount.com/thermowellcalc provides an online calculator to get a rough cut for your application. The standards behind these calculations is described on p. 254 of the manual.

Michelle highlighted why long sensor wires should be avoided. It’s better to wire into a multiplexer or DeltaV CHARM to run the signal back to the control system. Pages 86-89 describe the issues with and solutions for long sensor wires.

What the recommendations for high accuracy measurements? Matching a transmitter to the sensor improves the accuracy of RTDs up to 7 times. Each RTD has unique characteristics which the transmitter can adjust for. With RTDs use 4-wire installation for optimal performance. See pages 33-34 of the manual.

Michelle showed a video about the advantages of diagnostics. Transmitters with diagnostics check for measurement reliability, help avoid measurement failure such as sensor failure with hot backup. It can check for limits to make sure the process control for the loop is not suboptimal. See pages 22-25 for more about these diagnostics.

Every 3144P have hot backup capability.

Michelle’s final topic was installation best practices from pages 61-62 and 77-81 of the guide. Some examples are mounting the transmitter as close to the sensor as possible, three considerations for grounding (pp 80, 120, 126). Many of the problems found in installations are caused by grounding issues. Temperature devices are more susceptible than pressure transmitters to grounding issues.

2 comments

  1. Jonas Berge says:

    Temperature transmitter diagnostics which also covers the temperature sensing element is great for the run & maintain organization in the plant. Operators can at a click of a button check if there is something wrong with the transmitter or sensor (or if it perhaps is a process upset) before they issue a work order. Similarly, maintenance technicians can check the diagnostics to verify it is a genuine problem before they apply work permits etc. and head into the field. Lots of unnecessary field inspections can be eliminated. Device diagnostics can be used to prioritize daily maintenance planning at the start of the day. Another interesting diagnostics is Statistical Process Monitoring (SPM); It may be used to detect hydrate formation in natural gas lines, scaling formation, and thermowell coating etc.

    Learn more about temperature sensor diagnostics from these two articles
    http://www.ceasiamag.com/article-4987-turninguptheheat-LogisticsAsia.html

    http://www2.emersonprocess.com/siteadmincenter/PM%20Articles/indautoasia0806_eddl.pdf

    Learn more about how to incorporate diagnostics in daily maintenance and turnaround planning from the white papers and guide found here:
    http://www.eddl.org/DeviceManagement/Pages/DeviceDiagnostics.aspx

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