knight1fox3
Member
OP
I would use a pressure compensated pump. This is pump that has a swash plate that adjusts the stroke of the pistons as a function of pressure so as pressure drops due to increase demand the stroke of the pistons in the pump is increased to generate more flow. As the flow demand decreases the pressure will rise and the piston stroke will go back to a neutral position. This keeps the pump from pumping more oil than what is necessary and wasting oil/energy over a relief valve.
That is exactly the type of pump being used (see attached PDF). So based on your feedback, it would seem that the main pressure relief valve is extraneous? Be that as it may, this what I have to work with and need to make it work as this equipment is already manufactured. It would seem that I may be working from under the train on this one. So if I have my PID instruction configured correctly, I will proceed with testing and post my results. If not, I will change my configuration to adjust the main system PSI in steps (say of 100psi or so).
You hydraulic designers are clueless and you shouldn't trust them and chances are you will end up under a train. You don't need to believe me but ask them this... How fast will the pressure change in the pipe between the pressure control valve when one of those proportional valves open? How fast is that relative to response of your 20ms PID update? I can stump almost all hydraulic designers with this simple question. Actually, I have found only one person that can answer that question, surferb from this forum and he isn't a hydraulic designer.
Indeed this may be the case, but I assure you it isn't intentional and may just be due to lack of experience in the industry. FWIW, the proportional valves being used are very expensive and are very responsive to abrupt pressure changes based on corresponding control signals. They are using a newly released Lynch proportional driver.