Loop Analyzer

A new version of ExperTune's PID loop analyzer includes a stiction check wizard. The wizard provides a simple way of measuring the stiction in the control loop. The wizard works on the installed valve, giving a true measure of the in-service valve stiction. Measuring the in-service stiction is more significant than measuring it when the valve is not in use.

If the measured stiction is larger than 1%, then repairing the valve can result in better performance and increased product quality. Reducing stiction may eliminate a troublesome cycle, resulting in a product made closer to specification with less energy. Checking a valve for stiction is the third of five steps to completely optimize the loop. The complete optimization steps are:

•Statistical analysis and diagnosis from normal operating data
•Power spectral density analysis to check for hidden cycles
•Check and correct valve problems including stiction, hysteresis and sizing
•Test for and characterize non-linearities; apply a characterizer to linearize the loop
•Find optimal PID tuning parameters

ExperTune includes all the tools needed to make completing the optimization steps simple. The company creates a full loop report including stiction analysis in Microsoft Word.

ExperTune, Inc., 4734 Sonseeahray Drive, Hubertus, WI 53033. Tel: 262-628-0088; Fax: 262-628-0087.