Fuzzy new ways with PID loops
15 Jan 2000
Every process engineer knows the basics of PID control algorithms, but a new controller from Status Instruments is said to introduce a novel method of calculating PID parameters, known as natural frequency tuning.
The Ascon QD controller combines this with fuzzy logic action to give smooth, precise control to demanding and critical processes.
The PID method used is claimed to be better than conventional techniques. It analyses the process response to demands (even very small ones) imposed by the controller, to calculate the natural frequency of the process. The instrument then calculates the fuzzy parameters from the optimised PID algorithm without any need for the operator to be involved.
This combined PID-fuzzy technique is said to enable fast, smooth responses to load, setpoint or ambient variations with little or no overshoot. The controller has a universal dual input front-end for connection to a variety of sensors including Pt-100.
