User manual

Released 03/2008 Rights reserv ed f or change in technical data! HYGROSENS INSTRUMENTS GmbH Postf ach 1054 D-79839 Löf f ingen Tel: [phone] Fax: [phone]
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LEVEL CONTROLLER FOR
CONDUCTING LIQUIDS
2 Description
2.1 Functional description
The control device is used for regulating level of conducting liquids like supply line
water, rain water or condensate. The measurement of level in the reservoir is done
with the help of electrodes, for which either contact surface of the reservoir walls or
self made rod type electrodes can be used.
With two independent circuits, simultaneous monitoring of both minimum and
maximum liquid levels and control of two different actuators are possible, for example,
an inlet valve and a pump.
In liquid reservoir, four electrodes (E1..E4) are mounted in the medium, at heights
corresponding to the required switching point. A fifth electrode is placed at the bottom
of the reservoir (not shown in sketch) which works as the reference electrode.
According to water contact, the fill level is indicated through 4 green LED´s L1 to L4. If
the reservoir is completely empty, the red LED glows.
For example, the lower pair of electrodes (E1,E2) can be used to control a filling valve
at the inlet. After release of the lowest electrode E1, the filling valve is switched ON
and switched OFF again on wetting of the second electrode E2 (Hysteresis).
For example, the upper pair of electrodes can be used to control a drain valve or a
pump. During contact with the topmost electrode E4, the drain valve is switched ON
and again switched OFF after release of the lower electrode E3 (Hysteresis).
The switching behaviour of the system (Filling/Empty) is to be configured over two
jumper plugs. The sensitivity of the electrodes can be adjusted through potentiometers
(approx. 15k ... 80kOhm).