Manfred Weber
Metra Mess- und Frequenztechnik in Radebeul e.K.
PC Vibration Measurement System VibroMetra

Operation mode

Operation mode

Characteristics mode

1. Characteristics mode
Records compressed values like RMS or peak.

Signal mode

2. Signal mode
Records real-time signals with the chosen data rate. Since these values may be very fluctuating the bar graph will show only the highest magnitude with the respective sign.

Data rate

3. Data rate
In Signal mode you can decide whether the signals are recorded with maximum or with adaptive data rate.
Maximum data rate
The full sampling rate of the USB device will be used for recording:
  • 10 kHz for the M302
  • 96 kHz for the M312
Adaptive data rate
The recording data rate is set according to the used low pass filters. The sampling rate will be sufficiently high to meet the Nyquist criterion.
Example: All channels use a 10 Hz low pass. It is not necessary to sample with the full rate of  96 000 Hz. The sampling rate can be reduced to  < 1000 Hz which will reduce the amount of data by 99 % without loss of information.

Digital input

4. Digital input
For automated test systems it can be advantageous to control VM-REC by an external trigger, which is a digital input of the USB devices. VM-REC starts when logic high level is detected and stops at low level.