Meggitt vibro-meter VM600 User Manual

HARDWARE MANUAL Document reference MAMPS-HW/E
VM600 machinery protection system (MPS) Edition 18 - March 2022
7-6
Shaft relative vibration with gap monitoring
PROCESSING MODES AND APPLICATIONS
The ratio between the maximum and minimum fundamental frequencies that can be tracked
should not be greater than 25:1. For example, if the minimum tracked frequency is 4 Hz, the
maximum tracked frequency cannot be greater than 100 Hz.
7.4 Shaft relative vibration with gap monitoring
(1) Description
The relative movement between machine parts can be measured by non-contact proximity
probes. The frequency range of these devices (for example, the TQ4xx series from the
Meggitt vibro-meter
®
product line) is typically DC to 10 kHz, so they can be used in both
position and vibration measuring systems.
Shaft relative (relative shaft) vibration is measured with the proximity probe mounted on the
machine bearing. This measures the radial vibration of the shaft relative to the bearing.
The following front-end components are the most commonly used:
• TQxxx proximity transducer + IQS signal conditioner
• TQxxx proximity transducer + IQS signal conditioner + (Intrinsically safe) GSV power
supply and safety barrier (applications).
The MPC4 allows the following two types of analysis:
a. Vibration monitoring, that is, the analysis of the AC component of the signal.
b. Gap monitoring, that is, the analysis of the DC component of the signal.
(Note: The gap is the initial distance between the transducer and the target).
(2) Block diagram
The processing performs AC-component and DC-component separation. This provides
signals corresponding to the vibration and gap values, respectively. Vibration processing is
done with a 10 kHz bandwidth and DC processing with a 1 Hz bandwidth. The low-pass cutoff
frequency can be set between 250 Hz and 10 kHz using the VM600 MPSx software.
Sensor
input
Figure 7-3: Block diagram showing relative shaft vibration with gap monitoring processing
Output 1
vib. value
Output 1
vib. alarm
Output 2
gap alarm
Output 2
gap value
RMS
Mean
Peak
Peak-Peak
Alarm level
detectors
AC
DC
Initial
gap

Meggitt vibro-meter VM600 Specifications

General

Brand	Meggitt
Model	vibro-meter VM600
Category	Protection Device
Language	English