mjp123gp
Member
Today I upgraded an L55 processor with an L82, which ended up being the 2nd unsuccessful attempt but thats a different story. After starting the process back up we noticed a few of the pumps that try to maintain a set pressure were surging up and down really fast. I traced the control back to a unconditioned PID command that was being executed every scan. Luckily I had ran into this a while back and remembered that the loop update time had to match the PID execution time and after a little programming got that running correctly.
Afterwards I started digging into it a little more just to find out why that actually makes such a big difference but I couldn't really find a detailed explanation on the Rockwell knowledge-base. I was hoping someone from here could explain a little better. If you have links to other posts i've missed, thats fine too.
Thanks
Afterwards I started digging into it a little more just to find out why that actually makes such a big difference but I couldn't really find a detailed explanation on the Rockwell knowledge-base. I was hoping someone from here could explain a little better. If you have links to other posts i've missed, thats fine too.
Thanks