Technical Instructions for
Correlation Sensors
Page 60
Correlation Sensors – Rev. 07 as of 20.04.2016
®
If the measurement medium contains substances (e.g. grease, lime) which may
sediment on the pressure opening, they must be removed in order to prevent
measurement faults.
The duct to the pressure measurement which is milled into the ground plate
must be flushed with water immediately after each de-installation to avoid sedi-
mentation. To do this, immerse the probe into water several times.
The cover on the pressure measurement can be removed for more extensive
cleaning purposes.
The opened pressure cell must be cleaned very carefully. Slightly move the
pressure probe in a container filled with water (e.g. bucket) to flush. Strictly avoid
touching the probe with fingers, brushes, tools, water jets and similar! Disregard-
ing invalidates the manufacturer warranty!
Important Note:
If sedimentation which cannot be removed prevents correct measurement the
sensor must be maintained by NIVUS.
1
Pressure sensor
Fig. 7-1
Wedge sensor with pressure measurement cell, bottom view
Due to physical reasons, level measurements performed by sensors with pres-
sure measurement cell are subject to long-term drift (see chap. 5.9). NIVUS
therefore recommend to calibrate sensors with integrated pressure measure-
ment cell twice a year regarding the respective zero point. The best results are
going to be achieved if the water level is as low as possible or if the sensor has
been removed from the measurement medium. The calibration procedure is de-
scribed in according Instruction Manuals of OCM Pro or PCM transmitters.
The combination sensors with pressure measurement cell are equipped with an
additional air filter with a dehydration agent on the connection plug. This dehy-
dration agent is subject to normal wear which depends on measurement dura-
tion, measurement interval, air pressure fluctuation and environmental condi-
tions. The filter wear is indicated by the dehydration agent turning from dark blue
to pale violet.
The air filter has to be controlled each time before use, replacing the battery or
reading out data. If the colour is beginning to change the air filter must be re-
placed by a new one of the same type.
Spare filters are available from NIVUS under Art. No. ZUB0 FILTER02 (also see
chapter 0).
