Be Certain, Be Diligent

Ray Peacock

What appears to be the end of the sensor purchasing process is just another test for the professional engineer. You've gone to great lengths to specify, find, and acquire the right device for the application. Don't blow it in the homestretch by not checking to see if it's the right sensor, with the right performance capabilities.

Things Happen
Taking steps to ensure you get what you ordered seems like a no-brainer. After all, when you finally get the sensor you've spent so much time and effort specifying and selecting, you'd think you would make certain the device meets your specifications. But not everyone does, and therein lays the problem.

In my experience, there are a few dozen things that can go wrong between the time you order and when you finally take delivery. I used to work for a premier sensor maker. Its manufacturing plant was in England, and we did sales and services in North America and Mexico. We took every precaution—including an incoming inspection and calibration test—before we shipped the goods to the end users. But even with all our efforts, something went wrong on occasion.

Belt and Suspenders
Keep in mind there's a lot at stake. Modern, high-efficiency, high-speed processing can make a lot of scrap in a very short period of time. If your sensor is not right, it could end up costing far more than the expense of testing. That's why it is essential that you inspect your sensor on delivery. Be sure you get the right device and that it meets your specifications.

I know that seems to go against the principles taught in SPC and Six-Sigma programs, but one-shot events are outside the scope of such disciplines. A new sensor is a one-time event, and a very critical one that needs to be 100% within specification when it's used. The responsibility for the deployed sensor's performance is yours, not the supplier's.