3/9/2016 12:04 PM | |
Posts: 129 Rating:
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Hi, From your post what I understood is 3 Pumps are used to build up pressure (say X Units) depending on a pressure set point (SP). And you are in simulation mode, so can't have Process value for pressure (PV). As all 3 Pumps are of fixed speed, the only option you have is controlling their Run command in the explained manner. Since we don't know how your process will react and it's dynamics, to keep things simple I propose this algorithm. 1) Process begins (Start of simulation) with predefined SP for Pressure and dead band for Pump startup. 2) PV is not equal to SP 3) Pump1 starts (Add 0.33 in Pressure value with fixed interval, say 1 second). So You should get PV = PV + 0.33 (Linear) 4) PV is still far less than SP hence Pump2 starts (Add 0.33 in Pressure value with fixed interval). Now you should have PV = PV + 0.66 (Linear) 5) PV is still far less than SP hence Pump3 starts (Add 0.33 in Pressure value with fixed interval). Now you should have PV = PV + 0.99 (Linear) It will take some time to get PV near to SP. Same way you can simulate reaction of PV when pumps are turned off. Try to feed this data in your simulation and let us know how it reacts. Also find attached Excel to see what I mean. AttachmentBook1.xlsx (125 Downloads) |
Last edited by: PSW2586 at: 3/9/2016 12:11:28 PM |
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3/28/2016 6:17 AM | |
Posts: 129 Rating:
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Hi, Sorry, but I did not get... Can you explain more
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4/2/2016 9:16 AM | |
Posts: 40 Rating:
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When a pump turns on, the pressure immediately increases by a preset amount. |
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