English (GB)
7
5.2 LC 221 controller
The LC 221 is a level controller specially designed for controlling
and monitoring the Grundfos lifting stations, Multilift MOG and
MDG. The basis for the control is the signal received continuously
from the piezoresistive, analogue level sensor.
The level controller switches the Multilift MOG and MDG pumps
on and off according to the liquid level measured by the level
sensor. When the first start level is reached, the first pump will
start, and when the liquid level has been lowered to the stop
level, the pump will be stopped by the controller. If the liquid level
rises up to the second start level, the second pump (only MDG)
will also start, and when the liquid level has been lowered to the
stop level, the pumps will be stopped by the controller.
Starts alternate between the two pumps (MDG).
In case of pump failure in one pump, the other pump will take
over (automatic pump changeover for MDG).
An alarm will be indicated in case of high water-level in the tank,
pump failure, etc.
Furthermore, the level controller has many more functions as
described below.
Fig. 7
LC 221 level controller for Multilift MOG
Fig. 8
LC 221 level controller for Multilift MDG
The LC 221 controller has the following functions:
• on/off control of one or two wastewater pumps based on a
continuous signal from a piezoresistive level sensor with
alternating operation and automatic changeover in case of
pump failure
• motor protection with motor-protective circuit breaker and/or
current measurement as well as connection of thermal
switches and a runtime limitation
• motor protection via operation-time limitation with subsequent
emergency operation. Normal operating times are max. 90
seconds with pipework DN 32 and 60 seconds with pipework
DN 40, and the operating time is limited to 3 minutes (see
section
6.4 Description of fault indications
, fault code F011,
F012).
• automatic test runs (2 seconds) during long periods of
inactivity (24 hours after last operation)
• re-start delay up to 45 seconds after returning from power
cut-off to mains operation (in order to even out the mains load
when several appliances are started up at the same time)
• setting of delay times:
– stop delay (time from the stop level is reached till the
pumped is stopped) - reduces water hammer if pipes are
long
– start delay (time from the start level is reached till the
pumped is started)
– alarm delay (time from a fault appears till an alarm is
indicated). This prevents short-time high-level alarm in case
of temporary high inflow to the tank.
• automatic current measurement for alarm indications
• setting of current values:
– overcurrent
– rated current.
• operating indication of:
– operating mode (auto, manual)
– operating hours
– impulses (number of starts)
– highest measured motor current.
• alarm indication of:
– pump status (running, fault)
– phase-sequence fault and missing phase
– thermal-switch failure
– high-level alarm (5 seconds delay)
– time for service/maintenance (selectable).
• selection of automatic alarm resetting
• fault log of up to 20 alarms
• selection between different start levels
• selection of maintenance interval (0, 3, 6 or 12 months).
As standard, the LC 221 has four potential-free outputs for:
– pump running
– pump failure
– high water-level alarm
– common fault.
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