Hi, I have looked at the other combustion threads and have a few questions relating to my own system. I have an in place system (predating my birth) that uses straight ratio control for gas to air.
It is a 2 loop system. With Temp PV and SP driving the Gas CV, and the second loop driving Air in direct ratio with Gas PV. Due to performance issues I am tasked with updating this. The main issues was overtemp. So I did a quick fix so at HI temp a set level of excess air used to cool the area down. I am now looking to correct this poor control scheme with a cross-limiting scheme.
I would like to know if my current scheme is unsafe and unwise to leave in place until I can generate a better control scheme?
The boss has dictated that there will also be a cooling control in the new setup. Does cross-limiting have that inherent in its design? if not i plan to add a similar cooling select to new system.
And cause Im new to PID I don't exactly understand how feeding A Temp PID loop to both Gas and Air Loops in cross-limit produce heat increase. I understand how the logic setup works by selecting different set points for air and gas, but how does the CV of temp loop give a good Air AND Gas SP with Air in ratio to Gas?
I am hopping around all day and leave forum open on computer so I apologies for any slow responses.
It is a 2 loop system. With Temp PV and SP driving the Gas CV, and the second loop driving Air in direct ratio with Gas PV. Due to performance issues I am tasked with updating this. The main issues was overtemp. So I did a quick fix so at HI temp a set level of excess air used to cool the area down. I am now looking to correct this poor control scheme with a cross-limiting scheme.
I would like to know if my current scheme is unsafe and unwise to leave in place until I can generate a better control scheme?
The boss has dictated that there will also be a cooling control in the new setup. Does cross-limiting have that inherent in its design? if not i plan to add a similar cooling select to new system.
And cause Im new to PID I don't exactly understand how feeding A Temp PID loop to both Gas and Air Loops in cross-limit produce heat increase. I understand how the logic setup works by selecting different set points for air and gas, but how does the CV of temp loop give a good Air AND Gas SP with Air in ratio to Gas?
I am hopping around all day and leave forum open on computer so I apologies for any slow responses.
