MMF VM22 User manual

Instruction Manual
Manfred Weber
Metra Mess- und Frequenztechnik in Radebeul e.K.
Meissner Str. 58 - D- 1445 Radebeul
Tel. [phone] Fax [phone]
Email: [e-mail] Internet: www.MMF.de
Vibration Meter
VM22

Published by:
Manfred Weber
Metra Mess- und Frequenztechnik in Radebeul e.K.
Meißner Str. 58
D-0 445 Radebeul
Tel. [phone]
Fax [phone]
Email [e-mail]
Internet www.MMF.de
Note: The latest version of this manual can be found at
http://www.mmf.de/product_literature.htm
Specification subject to change.
© 20 2 Manfred Weber Metra Mess- und Frequenztechnik in Radebeul e.K.
Full or partial reproduction subject to prior written approval.
Feb/ 7

Contents
. Purpose..................................................................................................................3
2. Function.................................................................................................................3
2. . The Sensor......................................................................................................3
2.2. The Measuring Instrument..............................................................................4
3. The Measurement Procedure.................................................................................4
4. The Batteries..........................................................................................................5
4. . Inserting the Batteries.....................................................................................5
4.2. Switching On and Off.....................................................................................6
4.3. Battery Display and Battery Type...................................................................7
4.4. Shut-off Timer................................................................................................7
5. Preparation of Measuring Points............................................................................8
5. . General Information on Measurement Point Choice.......................................8
5.2. ISO 08 6- Recommendations.....................................................................8
5.3. VMID Measurement Point........................................................................... 0
5.3. . How the VMID Measurement Point Functions..................................... 0
5.3.2. Mounting the VMID Measurement Point.............................................. 0
6. Measurement........................................................................................................
6. . Measurement Value Display.........................................................................
6.2. Measurement Point Detection.......................................................................
6.2. . Reading the VMID Data with the VM22...............................................
6.2.2. Entering the Measurement Point Text................................................... 2
6.2.3. Deleting Measurement Point Data......................................................... 3
6.3. Saving Measurands....................................................................................... 3
7. Viewing Saved Measurement Data...................................................................... 4
7. . Graphical Trend Display............................................................................... 4
7.2. Viewing Saved Measurement Values............................................................ 5
7.3. Deleting all Measurement Data.................................................................... 5
8. Measurement Evaluation..................................................................................... 5
9. Setting the Date and Time.................................................................................... 8
0. Calibration......................................................................................................... 9
. Sensor Check.....................................................................................................2
2. Reset Key...........................................................................................................2
3. Connection to a PC............................................................................................2
3. . Device Driver.............................................................................................2
3.2. VM2x Measurement Database....................................................................22
3.3. Firmware Update........................................................................................23
4. Technical Data...................................................................................................25
Limited Warranty....................................................................................................27
Appendix: Warranty
Declaration of CE Conformity

2
Figure : VM22 with sensor

Thank you for choosing a Metra Vibration Measurement Instrument!
1. Purpose
The VM22 has been developed, particularly, for the measurement and monitoring of
vibrations on rotating machines. The purpose of such measurements is to monitor
the condition of the machine in order to avoid unscheduled shut-down. Furthermore
vibration measurement is carried out prior to the distribution of new machinery and
subsequently to repair with a view to quality control and the issuing of product guar-
antees.
The basis for successful machine condition monitoring is the measurement of the vi-
bration severity over a longer period of time. Measurements are taken at regular in-
tervals of time and recorded.
The VM22 measures and records vibration velocity, also known as vibration sever-
ity, at a frequency range of 0 to 000 Hz. The VM22 specification corresponds to
the ISO 2954 regulations and is suitable for, among other things, the measurement
of machine vibrations on machines with a nominal speed at or above 20 min- , in
accordance with ISO 08 6.
An external piezoelectric accelerometer is used as the sensor, and is provided to -
gether with the instrument. The VM22 is fitted with an electronic measurement
point detector (VMID) which enables it to take routine measurements of a large
number of measurement points very effectively. A software package for transferring
the measurement data to a PC is also available from Metra.
In the common hierarchy of condition monitoring the VM22 is equivalent to “Level
”. This represents the long term monitoring of parameters with low technical and
personnel requirements.
For fault detection (“Level 2”), as a further step, spectral diagnostic measurements
are taken, which require a large degree of expertise and sophisticated measurement
technology.
In the development of the VM22 value was placed on simple operation and mainte-
nance requirements, which enable trained personnel to operate the instrument with-
out the need of being specially qualified.
2. Function
2.1. The Sensor
The VM22 operates with a piezo ceramic shear accelerometer. Piezoelectric vibra-
tion transducers are characterized by high precision and resolution with great robust-
ness. The accelerometer of the VM22 has an integrated electronic circuit for imped-
ance conversion in accordance with the IEPE standard. At the base of the sensor a
magnet has been integrated for mounting to the measurement point. In the center of
the magnet there is a contact point from which the identification number can be
read. The measurement point ID is saved in the available VMID measurement
points.
The coupling surface is protected by a metal cap which attaches to the sensors mag-
netic base.
3

2.2. The Measuring Instrument
2 shows the block diagram. The VM22 supplies the IEPE Sensor with 2 mA con-
stant current. At the sensor output, a vibration acceleration proportional AC voltage
arises, which is amplified in the instrument to produce an optimum level. The gain
switch-over takes place automatically. The subsequent analog/digital converter is a
Sigma-Delta converter with 24 bit resolution.
Further signal processing, such as filtering, integration (for calculating velocity from
acceleration) and RMS is carried out in the micro controller. The micro controller
also controls the graphic display, the USB communication and the storing of mea-
surements.
3. The Measurement Procedure
Measuring vibration velocity is a common procedure for assessing the running smooth-
ness of rotating machines. Vibration velocity, commonly known as vibration severity, is a
measurement of the energy expenditure of occurring vibrations. Vibrations are caused by
rotational imbalances, for example as a result of loose screws, bent parts, worn or slack
bearing clearance or dirt residues on fan blades. Often several factors have a mutually re-
inforcing effect. Besides rotary machines, the measurement procedure is also suitable for
reciprocating machines.
The specifications of vibration velocity measuring instruments are described in
ISO 2954. In the ISO 2954 a band filter for the vibration velocity of 0 to 000 Hz is de-
fined. The corresponding VM22 frequency response graph can be viewed in 3.
The displayed value of the vibration severity is the true RMS.
4
Figure 2: Block Diagram
IEPE
supply
Progr.
amplifier
A
D
Micro
controller
Display
Memory
Keys
Sensor
ID
USB
Power
supply

4. The Batteries
4.1. Inserting the Batteries
The VM22 is supplied by three alkaline standard cell type AAA (LR03) batteries.
NiMH batteries (HR03) may also be used. The minimum energy requirement of the
VM22 enables maximum utilization of the batteries.
Attention: Please switch the instrument off before changing the batteries. When
switched off, the contents of the memory are stored for a few minutes, without need
of the batteries, and the internal clock continues to run. If the batteries are removed
when the instrument is switched on or if they remain in the instrument until the bat-
teries have been completely discharged, the device will perform a new start once the
batteries have been changed. Following a 'new start' the date and time will need to
be newly set. Further settings as well as the saved measurands, are stored without
need of the batteries.
To insert the batteries, remove the two screws from the back cover of the device and
open the battery compartment (4). When inserting the batteries, please ensure that
their polarity is correct, (see the engraved markings inside the compartment).
5
Figure 3: The Frequency Response of theVM22
1 10 100 1000 10000
0,001
0,010
0,100
1,000
10,000
Hz
mm/s

Important:
•Always use three batteries of the same type and same date of manufacture.
•Remove old batteries from the instrument, and take out the batteries if the instru-
ment will not be used for a long period of time. Otherwise leaking battery acid
may cause severe damage to the instrument.
Please use your local collection point to dispose of batteries.
Batteries do not belong to the household waste.
4.2. S itching On and Off
The instrument is switched on by a short press of the ON-OFF button. A start screen
will be shown on the display for 3 seconds. (5).
This displays the hardware version number (the 3 digits before the point) and the
software version number (the 3 digits after the point) followed by the serial number
6
Figure 4: Battery Compartment
Figure 5: Start Screen

corresponding to the type label. The month and year of the last calibration are dis-
played (cf. Section 0) along with the memory capacity.
By pressing the ON-OFF button again the VM22 switches itself off. In addition, the
instrument has an automatic shut-off timer for saving the battery power (see cf.
Chapter 4.4).
4.3. Battery Display and Battery Type
In the upper left corner of the VM22 display there is a battery level indicator (6).
When the green battery symbol is full, the battery is fully charged.
While non-rechargeable batteries have a cell voltage of .5 V, NiMH rechargeable
batteries deliver only .2 V per cell. The VM22 battery indicator can be adjusted to
both voltages. To adjust the voltage remove the sensor from the VMID and press F2
to open the main menu. Here the battery type can be changed by pressing F to
scroll down to the menu option 'Instrument Settings' and then pressing OK. Within
the sub-menu select “Battery type” by following the same instructions as before (7)
and then by pressing F scroll between F “Alkaline” (non-rechargeable, .5 V) or
“NiMH Accu” (rechargeable, .2 V). Confirm your choice by pressing OK and exit
the menu by pressing F2 repeatedly.
If the power supply drops below 3.3 V when using alkaline batteries or below 3 V
with rechargeable batteries, the battery indicator becomes red. Further measurements
can be taken until the power supply reaches 2.8 V in keeping with the instrument
specifications. At this point the battery level indicator is completely empty and the
instrument switches itself off automatically.
If the VM22 is connected to a USB port, it will be supplied by the USB voltage in
order to spare the batteries. In this case, “External” is displayed on the screen in -
stead of the battery level indicator.
4.4. Shut-off Timer
The VM22 has a shut-off timer to help prolong the battery operating life. To set the
shut-off timer, remove the sensor from the VMID and press F2 to open the main
menu. From the main menu scroll down to the sub-menu option “Instrument Set-
tings” by pressing F and OK. Here the menu option “Shut-off timer” can be se-
7
Figure 6: Battery indicator upper left Figure 7: Select battery type

lected by pressing F and the timer duration options of , 5, 5 and 60 minutes can
be selected, alternatively to deactivate the switch off timer select “none”. The auto-
matic switch off timer starts to run after the last press of a button. If a button is
pressed then the timer restarts and counts down again according to the duration se-
lected.
5. Preparation of Measuring Points
5.1. General Information on Measurement Point Choice
When monitoring machines it is important to take measurements under the same op-
erating conditions, at the same measurement point. Choosing the suitable measure-
ment point is therefore decisive.
Where possible, qualified staff experienced in machine monitoring should be called
upon.
It is generally advisable to record machine vibrations near to their source. This helps
to reduce distortion of the measuring signal to a minimum when it is being carried
through transmission parts. Suitable measurement points include rigid machine com-
ponents such as bearing housings or gearboxes.
Light or mechanically flexible machine components such as cladding and casing are
unsuitable for the measurement of vibrations.
5.2. ISO 10816-1 Recommendations
The standard ISO 08 6- recommends bearing housings or their immediate sur-
roundings as preferred measuring location points for the measurement of machine
vibrations (Figures 9, 0, and 2).
For the purpose of monitoring a rotating machine it is normally sufficient to take
measurements in only one direction, either vertically or horizontally.
On machines with horizontal shafts and rigid foundations the largest vibration am-
plitudes occur horizontally. With flexible foundations, strong vertical components
also arise.
For the purpose of acceptance tests, measurement values are to be taken from all
bearing point locations at the center of the bearing and in all three directions (verti-
cal, horizontal and axial).
The following illustrations give a few examples of suitable measurement point loca-
tions.
8
Figure 8: Shut down time