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IX Booster Punta Lead /Lag Sc uence A. hardwired Ftnrctiorrs 1. None B. PLC Functions 1. Sequence the ptrnnps automatically ON and OFF, to following staging of pumps to maintain the discharge pressure setpoint through the PID control of the LEAD VI "D, and monitoring the percent speed of the LEAD VFD to dotennine when to STAGE LIP or STAGE. DCTab'N. 2. If the system DEMAND IS INCREASING, causing the LEAD VFD to increase speed to above it programmable value (default is 9211/r, speed), then start a virtual timer which, will be reset if the speed ever drops to below 92%, When a adjustable time delay as set by SCADArR MI (cLetjwlt is S ramutts) hers elapsed, commence turning ON or OFF the appropriate pumps to -o to the next stage. Each STAGING I II' control will have, acl_justable tirners I'or the affiected pumps to "smooth out " the dynamic change in Pressure conditions during the stage transition. It is the intent to have the LEAD VFD always be operation in an "efficient range of slush" while keeping the discharge pressure stable under I "ID CONTROL. This will also facilitate a reduction in energy costs. 3. If the system DEVAND IS DEC ICE ASIN -0, causing the LEAD VFD to decrease speed to below a programnmble value (default is 75'X, spocd), theca start a virtual tinier which will he reset if the speed ever rises above 75%. Wtren a adjustable t.irne delay as :net by SCADAi 1MI (del`ault is 5 minutes) has ehrpsed, cornmerace turning; CAN or OFF the appropriate Pumps to go down to the nest stage. Each STACTING DO%''N control will have wdjustable timers for the affected pumps to "smooth out" the dynamic change in pressure CC1nt1t1fIrIS flUl'llnk the Stage transition. 4, 11' no pumps arc ON, the. PLC shall monitor the discharge pressure and when it drops to a PLC programmable integer below the "active" pressure setpoint, then start a virtual I'LC: timer. If the discharge pressure stays below this "start-up" pressure setpoint for the errtir'e, urntiguous time (default ol` 5 minutes,), then command the LEAD VFD to come ON. The lower alien -up setpoint from the station discharge setpoint is to insure that the LEAD VFD will not have frequent starts and stops hovering around the station discharge. setpoint. 5. If only the LEAD VFD is ON, and the discharge pressure strops below the station setpoint causing the VFD to go to minimum speed, then start a programmable virtual PLC timer (default of 10 minutes) to shut down the LEAD VFD under this very low demand circunstance. 6. If llae TOO (Time of USE) function is active, only allow staking up through STAGE 4 (max Of 2 pumps ON). Do not allow, any 5l'aging N. 5 -7, tit this circumstance,, the UP STACTF timer would "not be active " at Stage 4. City of Santa Ana�RyF.P 15 -105 2 bTX15b