PID Loop Help

[matt_C_25]

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

[a062549]

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

[matt_C_25]

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.