Emerson’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.