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The floating switches have to close when they are floating on the surface. The floating switches
have to be connected floatingly. The required signal voltage is generated in the control system and
amounts to 5V.
Assignment of the float switches:
SWN1 = pump off
SWN2 = pump on
SWHW = high water alarm
For the usage in explosion-prone areas, either floating switches with the
corresponding permission, or intrinsically safe cut-off relays have to be
used.
The external sensor has to supply a measurement current between 4
and 20mA. The final value of 20 mA can be adjusted in the menu, so the
indication may occur in cm.
3.2.5 Utilisation of the internal sensor
A pressure sensor of 0 to 10 kPa is used as an internal sensor (0 to 1mWs, 0 to 100 mbar). Other
measurement ranges can be realised on demand. On the lower side wall, a hose screw connection
6/8mm is located which is intended for the connection of the immersion pipe. The sensor used
is designed as a differential pressure converter, so that barometric variations are eliminated. The
menu item “internal converter – adjustment” serves for the accurate adjustment of the zero point.
In order to equalise possible air leaks inside the pneumatic level
measuring device, the pilot tube has to be fully emerged from the water
after completion of the pumping process. For this purpose, the adjustment
of a follow-up time of the according duration is necessary. Alternatively,
the small-size compressor set for the air bubbler level measurement
system can be used.
3.2.6 Signal contacts
The 4 potential-free signal contacts are located in the upper circuit board (left).
The 4 signal contacts are free and programmable: the contacts 1 and 2 are opened in case of
power failure and the contacts 3 and 4 are closed in case of power failure.
If the power supply of the control is correct, then the signal contacts are closed in case of a fault
or signal.
3.3 Commissioning of the control system
After the complete connection of the pump cables, the mains power supply and the level sensor,
the parameters can be set after the mains voltage has been applied. Only trained personnel are
allowed to set those parameters.
Now the plant can be commissioned by pressing the key
. During the conduction of several
test runs, the set switch points have to be checked, and, if necessary, corrected.
