mellis
Member
Contr_Conn said:This is true for high speed PID loops with few ms loop update time
Most of applications of PID are for heating and filling applications with loop update time from 0.1 sec and higher
It will be nothing wrong if this task interrupted or executed with slight time deviation (less that 1%)
I agree that most temperature and level loops are pretty immune to this. But, update time is not the only factor for a loop to be susceptible to timing jitter. A loop with an update time of 500ms can be very picky about timing if it has a large amount of integral action. My experience in this area is with liquid blending flow control loops with integral settings around 0.01 sec/repeat. They definitely prefer stable timing.