PCE Instruments PCE-VM 40A, Руководство пользователя

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Manual
10
The three peak values X/Y/Z of the vibration velocity and the highest amplitude together with its main
frequency are displayed every second. On the right side of the screen a graph displays this value in the
frequency range. The diagram is scaled according to the limit curve. Higher magnitudes will be cut off.
Note: For the measurement of floor ceiling vibrations, there are different reference values for the vertical
(Z) direction. They are evaluated by the PCE-VM 40 and considered for alarms. In the FFT spectrum and
frequency display, however, only the horizontal directions (X / Y) are shown.
If the limit value curve is exceeded, “ALARM” is displayed below the main frequency. If the limit value is
exceeded, the following will happen:
- The red light will flash.
- The measurement values will be saved if event recording has been activated.
- The relay output will switch if it has been activated.
- A text message (SMS) will be sent if this option has been set up on the PCE-VM 40B.
Note: The alarm and recording functions will be activated after a delay of 30 seconds after leaving the
menu.
5.3 Measuring in accordance with BS7385
Measurement procedure
The British Standard BS 7385 is mainly used in the Commonwealth countries. It is less complex than the
DIN standard. Similarly to the DIN standard, it also measures the peak value of the vibration velocity in all
spacial dimensions. It is called “peak particle velocity” (ppv). The frequency range is not precisely
specified. The PCE-VM 40 uses the ranges 1 to 80 Hz and 1 to 315 Hz.
The standard provides reference values for short-time vibrations which are measured at the foundation
(see table). The reference values mark the limit above which cosmetic damage may occur, such as
cracks in the walls or ceilings. More minor damage is to be expected at twice the reference value and
greater damage at four times the guide value. In the case of sustained vibrations or excitation from
building resonance, the reference values need to be reduced by at least 50 %.
Residential and industrial buildings are differentiated.
Reference values for short-time vibrations without excitation of building resonances
Main frequency Residential buildings Industrial buildings
1 … 4 Hz
<0.6 mm displacement -
4 Hz 15 mm/s 50 mm/s
15 Hz 20 mm/s 50 mm/s
40 Hz 50 mm/s 50 mm/s
250 Hz 50 mm/s 50 mm/s