Application; Measurement Principle - holthausen elektronik ESW-small-Compact User Manual

holthausen
Electronic Vibration monitoring Unit
elektronik GmbH
ESW ® -small-Compact

3. Application

The ESW ® -small-Compact unit will be installed on machines like ventilators, blasts,
separators or decanters in order to protect these machines in the application against
inadmissible mechanical vibration. The unit monitor continuously the intensity of vibration
and warn reliably during exceeding of, inside the unit, adjusted limit values.
Moreover it is always possible to measure the actual vibration value at the analog output.
The permanent temperatur monitoring inside the case also is a feature of this unit
(see 18.1).

4. Measurement principle

The sensor converts mechanical oscillations into an electrical alternating voltage. The
subsequent electronics converts the AC signal into a DC voltage, which is equivalent to the
measured oscillation speed. The sensitivity, and thus the measuring range, can be selected
in the device using a switch. The electronics compares the measured value with two
threshold values G1 and G2, which can be set in the device using two potentiometers. The
threshold values can be steplessly set between 10% and 100% of the possible measuring
range. The analog output can be used as an aid for adjustment when setting the threshold
values G1 and G2. If the measured value crosses a threshold value the corresponding alarm
relay is switched after the expiry of a permanently set response delay period. If the measured
value falls below the threshold value the alarm is cancelled after the expiry of the release
delay period.
The response delay and the release delay depend on the version (see specific data sheet)
and can lie between 0.2s and 25s (fixed by factory).
Alternatively the device can also be equipped with alarm memory (see Point 16).
In addition, the measured value controls a constant current source. A current in the range 0
to 20mA or 4 to 20mA which is proportional to the measured value and corresponds to the
measuring range is delivered over the "analog output" cable terminals.
All important electronic components of the device can be checked using the self-test
functions of the device (Point 18).
All important functions are permanently verified in normal operation. The functions such as,
e.g., the relay test which would disturb the measuring operation, can be carried out by the
user when required the pressing the switch (S1).
Optionally the device can be delivered with a self-test on starting. This carries out a
complete function test every time the device is switched on (Point 18.3).
Attention: Pay attention on requirement by entrance in EEx-Zone
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