This application will control the start sequence of 3 pumps. Tank level is monitored via three float switches. The high level switch identifies when the tank level has risen to the level when one pump is needed to decrease the level to normal levels. The Level Ok float switch identifies when the tank level has fallen the level where pump operation is no longer required. The over level float switch identifies an overfill condition. Pump sequence is alternated to equalize the operation hours of each pump as much as possible. The 'Lead' pump is the pump that will operate the next the level rises and pumping is required. The 'Lead' pump is alternated between all three pumps(once each time the level rises and then drops to normal). In the event a single pump cannot meet the demand (OK level not reached within 10 minutes), a second pump is started to accomodate the load condition. After an additional 10 minutes without reaching the OK level the third pump is also started. After 10 minutes with all three pumps started, if the level OK has not been reached, the alarm output will pulse on and off in two second intervals. If at any time an over fill is detected, all pumps will continue to operate, and the alarm output will be on steady.
AN-105.pdf, Application Programs AN-105_EBB.dld, AN-105_HEC.dld, AN-105_PCS.dld, AN-105_SI.dld