Xylem DCX-22 SELF CONTAINED WATER LEVEL DATALOGGERS - Manual (Page 2)

KELLER AG für Druckmesstechnik DCX Operating Instructions
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Absolute measurement (DCX-22 / DCX-22 SG / DCX-22 AA)
The DCX-22 and DCX-22 SG instruments utilize an absolute pressure sensor. A second DCX-
22 is positioned on the surface as a barometer where low water depths are involved (as the in-
fluence of air pressure fluctuations must also be taken into consideration), and the air pressure
characteristic is recorded. The water level is then calculated in the PC program (Logger 4.x)
as the difference between the two measured values.
The DCX-22 should be pulled out of the measuring position to read out the data. The interface
connector is located in the instrument itself. The DCX-22 can be utilized with extreme flexibil-
ity, due to the fact that it has no cable.
In contrast to the DCX-22, the DCX-22 SG is fitted with a cable with a read-out connector on
its end. It is therefore possible to read out the DCX-22 SG without removing it from the meas-
uring position.
The DCX-22 AA has a second absolute pressure sensor integrated in the read-out unit (which
acts as a barometer) and automatically calculates the difference between the two measuring
values. This enables a direct read-out of the water level. The advantage of this solution when
compared with the DCX-22 VG (which utilizes a reference tube for air pressure compensation)
is that the entire system is hermetically sealed against exterior influences. The disadvantage is
that the resolution is slightly less than that of the DCX-22 VG.
The maximum measuring range is limited to 10mWC, due to signal loss in the cable between
the sensor and read-out unit.
DCX-22 SG DCX-22
DCX-22 AA