Data Flow Systems TCU800, Инструкция по установке и эксплуатации, Страница: 29 / 162

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U n i t O v e r v i e w
Principles of Operation
Simplex, Duplex, and Triplex Stations
The station type is determined by the number of pumps at the station.
Simplex
A simplex station consists of one pump. At a minimum, a simplex station uses the Off and Lead staging
levels.
Duplex
A duplex station consists of two pumps. At a minimum, a duplex station uses the Off, Lead, and Lag
staging levels.
Triplex
A triplex station consists of three pumps. At a minimum, a triplex station uses the Off, Lead, Lag, and
Lag2 staging levels.
The staging levels above are the required for a discrete float type system. For Analog systems the above settings must be
programmed into the TCU as set points with the exception of the Off. The additional set points; Lead Off, Lag Off, and
Lag2 Off, replace the single Off Float in the discrete float system. Both discrete and analog systems can use the option Low
Level and High Level discrete inputs as a backup alarm system.
Pumping Modes
The TCU can be configured to operate in two different pumping modes, “Pump Down” or “Pump Up.”
Pump Down
Pump Down mode is used to empty a well (as is typical in a lift station) by maintaining the well level
between the Off and Lead staging levels.
Pump Up
Pump Up mode fills a tank by maintaining the tank level between the Off and Lead levels.
Level-Sensing Systems - Discrete vs. Analog
A discrete system uses a device that provides an On/Off signal. These are typically float balls submerged into a wet well.
The floats are wired to the appropriate inputs on the TCU. The TCU then controls the operation of up to three pumps based
on input signals from these floats.
In an analog system, a variable, transducer-supplied 4-20mA or 0-5 V input that is wired to the TCU’s analog input is used
to control up to three pumps. The input is typically supplied by a pressure, level, or ultrasonic transducer. Analog systems
use Lead Off, Lag Off, and Lag2 Off set points in addition to the staging levels used by a discrete system.
Staging levels can be monitored using either a discrete system or an analog system. Pumps are automatically started and
stopped based on these staging levels.
Discrete System (Contact Closure Devices)
In a discrete system, the TCU controls the pumps based on up to six discrete input signals, typically float balls submerged
into a wet well. The floats are positioned at designated levels in the well to enable the pumps to be started and stopped
based on the detected contact closure. The float contact closures can be monitored with various voltage levels.
Low and High floats can be added as optional backup and alarm systems. When a low or high-level float is activated, an