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Model CA-2PDA Analog Controller
(Includes Redundant Float Based Control)
This specification covers a complete automatic pump control and alarm system responding to the ________________ level as shown on the plan drawings.
The controller shall provide duplex pump control based on a 4-20 mA process level input that represents a 0-______ foot level excursion. The controller shall be used in a pump-down control application for automatic control of two constant speed pumps. The controller shall contain individually programmable differential control stages for the Low Alarm On/Off, Lead Pump On/Off, Lag Pump On/Of and High alarm On/Off. The controller shall have an integral operator interface comprised of a 4-line by 12-character backlit LCD display and six pushbutton switches. The display backlighting shall be enabled whenever a pushbutton is pressed. The backlighting shall automatically turn off following a period of keypad inactivity. The LCD display shall provide not only the requisite status information (e.g. tank level & pump operating information) but shall also provide a convenient mechanism by which the control setpoints can be adjusted. The operator shall be able to view the status displays and, while there, conveniently change the pump On/Off setpoints and alarm On/Off setpoints.
The controller shall contain a redundant control strategy that is enabled by the connection of one or two float switches. When using a single high-level float switch the pumps shall be called into service sequentially by the closing of the Pump Add float switch. When the Pump-Add float closes, the controller shall energize a lead pump output. If the float switch remains closed, the controller’s internal ‘Pump Add’ timer shall expire and call for the Lag pump. The ‘Pump Add’ timer shall be adjustable from 0-99.9 seconds. The redundant control’s high-level, Pump Add float-switch shall be mounted above the normal operating range of the controller’s primary analog control system’s High Alarm ON setpoint. The pump outputs are deactivated when the ‘Pump-Add’ float opens and the controller’s internal Off-Delay timer expires. The Off-Delay timer shall be keypad programmable from 0-10.00 minutes. When using two float switches the pumps shall be called into service sequentially by the closing of the high-level Pump-Add float switch. The pumps shall then be removed from service upon the opening of the low-level Pump(s) Stop float switch.
At the end of any pumping sequence, the controller’s alternator shall advance to the next pumping sequence. The controller shall have provision for an external alternator selector switch that shall allow the selection of either a 1-2, Auto or 2-1 pumping sequence. The controller shall contain four relay outputs. Two outputs shall be used for pump control. The controller shall contain a programmable alarm output (Low Alarm, High Alarm or both Low and High Alarm) and alarm monitor relay output. The alarm output shall automatically silence and reset following the end of each pumping cycle. The controller shall accept an external alarm acknowledge/silence input. The controller shall be UL 508 Listed. The controller shall be a CONTEGRA CA-2PDA.