In last week’s post, RTD or Thermocouple for Temperature Measurement?, we shared the first of several education videos on temperature measurement. Emerson’s team who manages the Rosemount Temperature products and services developed these videos. Here’s a link to the complete set of videos.
In today’s post, I’ll highlight the 4:17 YouTube video, Temperature Insights – Accuracy & Reliability Brief Video. For the temperature sensors you use in your process manufacturing or production facility, it’s important that they be accurate, repeatable, and reliable.
For the best fit for your application, you need to consider three things. First, identify temperature measurement performance factors. Second, calculate measurement accuracy. Third, employ advanced transmitter techniques. Performance factors are influenced by sensor accuracy, repeatability, and stability. Here is a nice graphic from the video explaining the concepts of repeatability and accuracy.
Stability is the transmitter’s ability to avoid drift and maintain accuracy over time.
The most common way to calculate temperature measurement accuracy is using a method, total probably error (TPE). It reflects the probable error from the transmitter, sensing system, and anticipated installation conditions.
Some advanced transmitter techniques highlighted in the video included line voltage filtering, transient protection from high voltage spikes caused by lightning or electrical power surges. Hot backup at the transmitter can seamlessly switchover a failed sensor to its redundant pair. When using RTDs for the temperature sensor, Callendar-Van Dusen (CVD) constants can provide 7x greater accuracy.
You can find the source of these concepts and more in The Engineer’s Guide to Industrial Temperature Measurement. If you don’t have already have this guide, order your complimentary copy.
You can also connect and interact with other temperature measurement specialists in the Temperature instrumentation track of the Emerson Exchange 365 community.