pauly
Member
Does any body have experience in gas air ratio control for a combustion system? I have seen a few descriptions of ratio control with cross limiting and wondered how it was applied in the control system. One example I have seen mentions scaling the fuel and air flows so that at the correct mix the ratio between gas and air is 1:1. This doesn't help if I need to change the ratio.
I am measuring the air flow compensated for pressure and temperature and measuring the gas flow compensating for pressure, and I intended to employ a P.I.D controller for the air flow control (output is to a flow control valve) with a set point from the thermal demand, and employ a P.I.D controller for the gas flow with its' set point derived from the air flow divided by the ratio required.
I would welcome any feed back from any one with any experience with this especially as I am not sure how the cross limiting function is employed.
Practical examples would be very welcome. I am using a Controllogix PLC
Thanks in advance
I am measuring the air flow compensated for pressure and temperature and measuring the gas flow compensating for pressure, and I intended to employ a P.I.D controller for the air flow control (output is to a flow control valve) with a set point from the thermal demand, and employ a P.I.D controller for the gas flow with its' set point derived from the air flow divided by the ratio required.
I would welcome any feed back from any one with any experience with this especially as I am not sure how the cross limiting function is employed.
Practical examples would be very welcome. I am using a Controllogix PLC
Thanks in advance