Peter Nachtwey
Member
The levels won't change in a non-continuous way@Peter I agree in principle, but I wonder about the non-continuous nature of the flow each time a pump or added.
I don't like the idea of 3 pumps with 3 INDEPENDENT integrators trying to follow a set point. I see this as having a too many degrees of freedom problem if there is only one set point for all 3 pumps. There would need to be a method of keeping all 3 pump's integrator the same. That is doable. However, they can't be independent.What if the lead pump is P-only, and the rest of the three pumps are I-only with a PV deadband equivalent to 60-90% of the lead pump speed and a CV range of 0-240%, with each lag pump's 20-100% taking one-third of that range.
Why make this complicated? skyfire claims he has a foot of band to work with. He also has a way of keeping track of which pump to start next. I don't know if he has a good method of stopping the long running pump. It isn't clear to me that the pumps are speed controlled, only that there needs to be a soft start but the drive should be able to handle that and the soft start should be relatively fast compared to how fast the level changes so the ramp time can be ignored.