It's hard to believe that a major manufacturing company is still using PLC-5's in 2022 but we were.  I recently upgraded this entire system to a new controller.  The heart of the process is a Werner & Pfleiderer twin screw extruder (400hp).  The DCS also controls a material vacuum convey system with three independent vacuum pumps.  Resin powder is transferred from bags to various hoppers and then to a third floor mixer.  The mixer prepares batches by dosing an additive via a Coriolis meter.  The batch gets mixed with pure resin with two KTron gravimetric feeders then fed to the extruder inlet.  Twelve heated (and water cooled) zones on the extruder manage the temperature of the reaction with independent PID loops.  The finished material gets flattened with nip rolls, solidified on a water cooled belt cooler and turned into powder through a pin mill and hammer mill.  The final step is vacuum conveyed into finish product on RiceLake weigh scales.