Grundfos SE1 50 Instrucciones De Instalación Y Funcionamiento página 18

8.3 Pump controllers
The following LC, LCD, DC and DCD pump controllers are
available for level control:
LC controllers are for one-pump-installations and LCD controllers
are for two-pump installations.
• LC 107 and LCD 107 with air bells
• LC 108 and LCD 108 with float switches
• LC 110 and LCD 110 with electrodes
• DC for one-pump installations
• DCD for two-pump installations.
In the following description, "level switches" can be air bells, float
switches or electrodes, depending on the pump controller
selected.
LC LCD
The LC controller is fitted with two or three level switches:
One for start and the other for stop of pump. The third level
switch, which is optional, is for high-level alarm.
The LCD controller is fitted with three or four level switches:
One for common stop and two for start of the pumps. The fourth
level switch, which is optional, is for high-level alarm.
When installing the level switches, observe the following points:
• To prevent air intake and vibrations install the stop level
switch in such a way that the pump is stopped before the
liquid level falls below the upper edge of the clamp of the
pump.
• In pits with one pump, install the start level switch in such a
way that the pump is started at the required level; however,
the pump must always be started before the liquid level
reaches the bottom inlet pipe to the pit.
• In pits with two pumps, the start level switch for pump 2 must
start the pump before the liquid level reaches the bottom inlet
pipe to the pit, and the start level switch for pump 1 must start
this pump correspondingly earlier.
• If installed, always install the high-level alarm switch about
10 cm above the start level switch; however, the alarm must
always be given before the liquid level reaches the bottom
inlet pipe to the pit.
For further information, see the installation and operating
instructions for the pump controller selected.
Warning
Float switches used in potentially explosive
environments must be approved for this application.
They must be connected to the Grundfos LC, LCD
108 pump controller via the intrinsically safe LC-Ex4
barrier to ensure a safe circuit.
18
DC DCD
The Dedicated Controls system consists of a CU 362 control unit
connected to one or two IO 351 modules. An optional IO 111
sensor module can be connected to each pump.
The CU 362 is the 'brains' of the system and must be
incorporated in all installations. The units in the system can be
combined in different ways according to the user's needs.
Dedicated Controls controls the pumps by means of power
contactors and IO 351 modules. Power contactors, cables and
other high-voltage components should be positioned as far away
as possible from the control system and the signal cables.
Dedicated Controls is operated via a user-friendly control panel
on the CU 362 or via a PC. Wireless remote control is available
throughout the world, using a PC or mobile phone.
Dedicated Controls can be integrated into a user's existing
SCADA system.
Fig. 12 Start and stop levels
Make sure that the effective volume of the pit does not become so
low that the number of starts per hour exceeds the maximum
permissible number. See section
Max.
Min.
13. Technical data.