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Hello All:
I have a rather unique application that I wanted to bounce off all "the experienced" out there. I am controlling a gas flow application that uses canisters to process the gas. Each canister is limited to a maximum flow and since there is a varing load, we have banks of modules that are selectable in combinations. The control system
can activate any combination of modules from 1 to 18. The typical load requires approximately 9 to 10 modules to be online. This is where the dilemma arises. Occasionally the variation in load demand (reading of inline flow meter) causes an operating point that teeter-totters between the selection of modules (i.e. between 9 and
10) and every time a transition occurs, an initial surge is generated in the system that takes a few minutes to settle out and therefore sets up a sort of unstable process. Once the demand increases and generates an operating point well inside the bracket of selection, the problem subsides. To remedy this, we are thinking
of building in some sort of hysteresis into the calculation (of modules via flow) to try to avoid this. Does anyone have any better ideas?
Thank you, in advance, for you input.
Brian Romano
PACsys, LLC
I have a rather unique application that I wanted to bounce off all "the experienced" out there. I am controlling a gas flow application that uses canisters to process the gas. Each canister is limited to a maximum flow and since there is a varing load, we have banks of modules that are selectable in combinations. The control system
can activate any combination of modules from 1 to 18. The typical load requires approximately 9 to 10 modules to be online. This is where the dilemma arises. Occasionally the variation in load demand (reading of inline flow meter) causes an operating point that teeter-totters between the selection of modules (i.e. between 9 and
10) and every time a transition occurs, an initial surge is generated in the system that takes a few minutes to settle out and therefore sets up a sort of unstable process. Once the demand increases and generates an operating point well inside the bracket of selection, the problem subsides. To remedy this, we are thinking
of building in some sort of hysteresis into the calculation (of modules via flow) to try to avoid this. Does anyone have any better ideas?
Thank you, in advance, for you input.
Brian Romano
PACsys, LLC