SD_Scott
Member
Earlier you noted the driven equipment is a dyno. I am assuming that this is a test cell and being a two shaft engine it will drive a generator eventually. If this is true I think you are well in good control at 1%. For example if you are in island mode(stand alone gen set) 1% is fine. Plus in droop mode you will droop the freq by maybe 10% based on the load. If you are syncing to a larger system you will be coupled electromagnetically through the generator. The power turbine will run at the system freq(gearboxes ....). That is way over simplified but you get the idea. If this is a compressor or pump application then I still think you should be fine. PCD is an indication of the engine performance. If you try to open the fuel valve too quickly you could upset the engine. By knowing the PCD you can limit the fuel valve from opening too much. Its been some years since I worked on an old Saturn. The item you mentioned above that takes PCD and maybe fuel pressure is possibly a proportioner that limits the valve based on inlet fuel pressure and PCD. Not sure Though. Anyway you can just make an array in the PLC and use it like a look up table, or do a calculation. Basically if the engine is at idle the PCD is low and you don't want to dump a bunch of fuel into it. Another example would be if you were running on load and the load increased because someone started a motor. The PID is going to respond by increasing the fuel flow. If it takes a while to respond the reset windup will cause the fuel valve to continue to open. By not considering the PCD you could cause the fuel mixture to richen up and eventually stall the engine. Many situations like that.
Hope this helps.
Hope this helps.
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