How to adjust the PID when the instrument exhibits divergent oscillations
Thread Content
This post was last edited by leng*ngli on 2009-12-12 at 16:47. I would like to ask for advice – I’ve encountered a common problem in production: one of the instruments tends to experience periodic oscillations during operation. Even after manually adjusting it to normal, this issue reoccurs once automatic mode is activated. I’m thinking it must be a problem with the PID parameters! Could some expert please help solve this? Thank you! ! !
There must be an issue with the PID parameter tuning. PID control is the most commonly used control method in industrial processes. However, the presence of large time lags in industrial systems severely affects their stability, resulting in larger overshoot, longer adjustment times, and even oscillations or divergence, which significantly deteriorates the dynamic performance of the systems. If divergent oscillations occur, switch to manual mode immediately; once the system stabilizes, increase the proportional band or integral time, or decrease the derivative time, and then resume automatic operation. The larger the proportional band, the smoother the transition process, but the greater the error margin. The smaller the proportional band, the more likely oscillations are to occur during the transition process.