Posted 17 Dec 2019 Hello everyone, I am need some help with a project, we are using liquid nitrogen to cool a product which runs on a conveyor through a tunnel which has liquid nitrogen controlled by a proportional valve using a thermocouple and a PID loop in the PLC currently i have a PIDE loop set in the PLC the temperatures have been scaled (-150 to + 50 PV and set points from -20 to -100) to a range 0f 0 (-150) to 200 (+50) output from the PIDE is inverted for analogue output 0 - 10V What i want to know is - is this right in terms of scaling or should i be looking to do this another way dont have much experience with PID in PLCs so any advice would be greatly appreciated Regards Matt Share this post Link to post Share on other sites
Posted 29 Dec 2019 Dare i ask, does it work? If so why do you think it needs work? This is a good place to read about PID instructions, so a search of here and maybe a YouTube video? Let us know the issue and someone here can chime in Share this post Link to post Share on other sites
Posted 6 Jan 2020 Thanks for the reply, Not sure if it works yet as only bench tested, i have thermocouples connected and measured the analogue output which is going in the right direction. will just have to see what happens when we test it for real. Share this post Link to post Share on other sites