Pump Lead/Lag Simulator

Auto pumps share a conventional DP PI speed command. Positive SP minus measured DP increases speed. Integral gain multiplies pressure error and simulated minutes. Output stays between Minimum and Maximum Auto speed. Manual pumps use their own speed and are excluded from automatic staging and alternation. System Off, pump Off and latched faults override automatic run timers.

Assist starts the second Auto pump after high lead speed and DP deficit persist for the configured delay. It stops the lag pump after low speed and adequate DP persist, subject to minimum run time. Standby reserves the second Auto pump for takeover; timed alternation can briefly overlap pumps. The new lead must prove running and ramp near the old lead's speed before release. Pressure can change during handover.

A drive trip stops the affected physical pump immediately and latches its alarm. Missing proof leaves the motor running until the proof timeout latches it out. Remove the injected fault, Apply, and Reset alarms to restore eligibility. Fault reset is queued while paused. No available Auto pump means automatic demand can remain unmet.

Two identical illustrative pump curves feed a common resistive circuit with ideal check valves. Pressure and branch flows come from the parallel operating point; adding a second pump does not automatically double flow. Speed ramps over the configured full travel time. Water inertia, pipe storage, cavitation, power, heat transfer and detailed building hydraulics are omitted.

All timing, tuning and model values are editable teaching examples. This is not a physically validated model, pump selection or manufacturer protective sequence. Live edits apply at a simulation boundary; Reset restores run-start settings. Trend inspection changes the view only.