PowerFlex 750-Series AC Drives User Manual

Using DeviceLogix G-15Example 4: Wet Well OperationThis example demonstrates how basic control logic can be used for simpleapplications. It is assumed that the PowerFlex 755 has an I/O moduleinstalled in Port 4.Figure G.3 Wet WellInflowCritical High Level SensorHigh Level SensorLow Level SensorOutflowThe application consists of the following discrete I/O:Type Name DescriptionInputs Fault Reset pushbutton Used to reset any faults or alarmsCritical High Level sensor Indicates a critically high level. It is normally a backup to the HighLevel sensor and is also used to detect if the High Level sensor isfaulty. When ON, the drive will operate at an even higher outputfrequency in case it is due to a high inflow.High Level sensor Indicates the well is at a high level and it is time to start pumping(normal operation). The drive operates at a ‘normal’ rate unless theCritical High Level was reached.Low Level sensor When OFF, it is used to indicate that the well is empty (as long asthe High and Critical High Level sensors are also OFF). The drivestops operating (end of pumping cycle).Outputs Sensor Fault pilot light Indicates that there is a problem with either the High Level or LowLevel sensorsToo Much Time Alarmpilot lightCritical High Faultflashing light / alarm hornIf the drive operates for more than the normal amount of time it takesto empty the well, there may be increased inflow or perhaps the LowLevel sensor is stuck ON. An alarm indication is made and the drivecontinues to operate.Indicates a critically high level that requires immediate attention.PowerFlex 750-Series User Manual – Publication 750-UM001C-EN-P – September 2009