Data Flow Systems TCU800, Инструкция по установке и эксплуатации, Страница: 30 / 162

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alarm is issued and normal pump control is overridden.
Note: If the Low float is not going to be used, it must be disabled in the TCU’s local configuration for the TCU’s pump
control operations to function normally in automatic. Failing to disable the Low float configuration in this situation, results
in a false alarm condition. This false alarm condition occurs because an unconnected Low Float input signal indicates to
the TCU that the wet well is too low to operate pumps, or OFF, therefore the TCU will not permit pumps to operate. The
TCU expects Low float input’s normal/safe state to be ON which indicates the Low Float floating, to permit automatic
pump operation.
Staging Levels in Discrete System
Pumps are automatically started and stopped based on staging levels. The illustration below shows the behavior of pumps
at each staging level in a discrete system. Both a lift station (pump down mode) and a storage tank (pump up mode) are
shown.
Staging Levels in Pump Down Mode (Discrete System)
This chart describes the normal function of the TCU’s eight staging levels when used in Pump Down mode, such as that
used in a lift station. Note that not all of these levels must be configured for a lift station. The minimum number of levels
required depends on the type of station – simplex (one pump), duplex (two pumps), or triplex (three pumps).
Low Level
All pumps are stopped and alarms are activated. Low is active when the well’s
level is
below Low level. Must be set below all other levels.
Off Level
Minimum operational level of a well. All pumps are stopped when the well’s
level is
below
the Off level.
Lead Level
Lead (first) pump is started. Lead is active when the well’s level is
above
the
Lead level.
Lag Level (duplex and triplex stations
only) Lag (second) pump is started. Lag is active when the well’s level is above the
Lag level.
Lag2 Level (triplex stations only)
Lag2 (third) pump is started. Lag2 is active when the well’s level is
above
the Lag2 level.
High Level
All pumps are stagger started and alarms are activated. High is active when
the well’s level
reaches
High level. Must be set above all other levels.
Staging Levels in Pump Up Mode (Discrete System)
The following paragraphs describe the function of the TCU’s eight staging levels when used in Pump Up mode, such as
that used in a storage tank. Note that not all of these levels must be configured for a lift station. The minimum number
of levels required depends on the type of station – simplex (one pump), duplex (two pumps), or triplex (three pumps).
High Level
All pumps are stopped and alarms are activated. Low is active when the tank’s
level is
above High level. Must be set above all other levels.