A Control Design reader writes: We have several temperature, pressure and flow sensors on a new medical-device cleaning skid that we are developing. These instruments are connected to a PLC as 4-20 mA inputs, and there is also a 4-20 mA output used to control a pump motor speed. A recent failure of a flow sensor brought the process skid instrumentation to my company's quality manager's attention. He asked how we know that the temperatures, pressure and flow are accurate, and how do we know that we are cleaning properly.
I've been tasked to write a procedure for troubleshooting, calibrating and testing the 4-20 mA instruments on the skid. I can probably stumble through this, but what are some best practices for troubleshooting the analog circuits to the PLC; how do I calibrate the instruments; and how should I periodically test the devices? Should I add programming to the PLC and HMI to simplify these functions?
The tiny EZminiWiFi is a godsend for the plant maintenance engineers who need to make a minor modification to the HMI program or, for that matter, the PLC program. It's very easy...
Discover the benefits of American-made automation products, including stable pricing, faster delivery, and innovative features tailored to real-world applications. With superior...
Over the past 50 years, the automation technology landscape has changed dramatically, but many of the underlying industry needs remain unchanged. To learn more about what’s changed...
Watch EZAutomation's recent feature on the popular FOX Network series "Manufacturing Marvels" and discover what makes them a force to be reckoned with in industrial automation...
