PCE Instruments PCE-VT 2700 Benutzerhandbuch Seite 15

By means of the function key "FUNC.", you can select the measurement function which is either
acceleration measurement (m/s²), velocity measurement (mm/s), displacement measurement (mm),
frequency measurement (Hz F) or revolutions measurement (RPM). When you measure the revolu-
tions, you must multiply the reading by 10. To make a selection, press the "FUNC." key several times
until the desired measurement function is displayed.
By pressing the "HOLD" button, you can hold the maximum value of your measurement. "MAX" will
appear in the upper area of the display. You can deactivate this function by pressing "HOLD" again.
The "METRIC / IMPERIAL" key is used to set the units. For acceleration measurement, the units m/s²
and F/s² are available, for velocity measurement, you can select inch/s or mm/s and for displacement
measurement, the units mm and mil can be selected.
When you work with headphones, you can control the volume (1 ... 8) by pressing the "VOL" key
several times until the desired value is indicated in the display. If machines or bearings are operated
under the same circumstances, you can use this device to carry out reference measurements. By
analysing these data, irregularities of the individual machines can be detected to recognise possible
faults at an early stage. Make sure that these measurements are always carried out at the same spots
in order to achieve high accuracy. The device will power off automatically 5 minutes after a key was
pressed. InF1 means that the measurement range was exceeded. The Low Bat symbol will appear as
soon as the supply voltage falls below 2.1 V. The measurements lose their validity. Urgently replace
the batteries.
5.2 Battery replacement
Switch off the device and remove the battery compartment cover. Remove the batteries and insert some new ones
(4 x 1.5 AAA batteries). Close the battery compartment cover.
6 Further information on vibration measurement
Vibration measurement provides reliable information that allows conclusions regarding the mechanical condition of
a machine or product. Ideally, a machine has very little or no vibration as this indicates that the motor as well as the
peripheral devices such as gears, fans, compressors and other devices are sufficiently balanced and aligned and
correctly installed. In practice, a high percentage of installations are far from ideal which is due to incorrect align-
ment and balancing and results in higher strain on load-bearing parts like bearings. This causes high strain on and
wear of important parts and thus inefficiency, heat generation and production downtime. Of course, this normally
happens at the most inconvenient and economically most inappropriate time and causes expensive production los-
ses. Vibration increases as wear and deterioration of mechanical parts rises. By regularly controlling the vibration of
faultless mechanical parts, you can detect deteriorations before they cause problems. This means that you are in a
position to order replacement parts in time and maintenance work must only be carried out when required. This is
to avoid expensive and unnecessary stocks of replacement parts, which brings financial advantages. Unanticipated
interruptions cause production downtime. Defective machines and equipment are often repaired in a hurry so that
production can be continued as soon as possible. Regardless of how precisely the staff works, it is not always
possible under these circumstances to carry out repairs correctly. This can in turn lead to machine and equipment
downtime again. A predictive maintenance schedule according to which important factors like vibration are measu-
red on a regular basis does not only allow you to reduce interruptions in production but also to make maintenance
work more effective. This increases product quality and productivity.
The term "trend" is very important to know in connection with vibration measurement. A trend indicates how a moni-
tored parameter behaves over time. If vibration measurements have been made and plotted over a certain period of
time, the resulting graph shows the progress or the deterioration of a certain machine. Immediately after installation,
it is possible that the vibration level decreases slightly as the machine is run in, no matter if the machine is new or
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