Wednesday, February 11, 2015

Quickly Identify Thermal Measurement Points for Data Acquisition

Temperature monitoring is a process that traditionally involves an amount of guess work. In this post we discuss how a thermal imaging camera can be used to quickly and easily identify temperature problem areas, and how a Data Acquisition (DAQ) instrument can be used to reliably and accurately monitor temperature-sensitive areas long term. 

Fig 1. Traditional Temperature characterization flow

Traditionally, you would use temperature probes with a data acquisition device to measure temperature on different points on you device under test (DUT). The process of identifying temperature sensor locations has been based on knowledge of the design and some intuition. It’s not uncommon, for example, for the designer to simply guess at the right location when placing temperature sensors. The process  would be very similar to the flow diagram in figure 1 here.

However with the use of a thermal imaging camera, you can quickly and intuitively find the hotspots  in your design early on in your design validation process. The thermal imager is great for finding hot or cold spots in your device. However, the limitation of the thermal imager is that it is a line of sight measurement which limits its effectiveness when the device needs to be in an enclosure. Because of this limitation you would still need a data acquisition device with temperature sensors to fully qualify your device not only when it is in it's enclosure, but also in different ambient conditions and under different load conditions to understand your temperature profile even more. This new temperature characterization flow is shown in figure 2.
Fig 2. New Temperature characterization flow.

In these types of temperature characterization models, Keysight Technologies has two products that really complement each other. The 34970A/34972A data acquisition systems, and the new U5855A thermal imager. While the 34970A/34972A has been recognized as a leader in low cost data acquisition for many years, the U5855A is a new product line for Keysight.

You can watch the video below for a quick 5 minute how-to tutorial on the process of thermal characterization.

For more information, you can also watch a webinar presented by me that discusses the use of a thermal imager and touches on some of the basics of temperature sensors and the use with a 34970A/34972A. You can find that recording here.