MMF VM31 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: [email protected] Internet: www.MMF.de
Human-
Vibration
Analyzer
VM31
(Valid from version xxx.016)

Published by:
Manfred Weber
Metra Mess- und Frequenztec nik in Radebeul e.K.
Meißner Str. 58
D-01445 Radebeul
Tel. [phone]
Fax [phone]
Email [e-mail]
Internet www.MMF.de
Note: T e latest version of t is manual can be found at ttp://www.mmf.de/prod-
uct_literature. tm
Specification subject to c ange.
© 2014 Manfred Weber Metra Mess- und Frequenztec nik in Radebeul e.K.
Full or partial reproduction subject to prior written approval.
Jan/ 19 #194

Contents
1. Purpose.................................................................................................................2
2. T e Device at a Glance.........................................................................................2
3. Fundamentals of Human Vibration Measurement................................................3
3.1. Introduction...................................................................................................3
3.2. EU Occupational Healt Directive 2002/44/EC............................................4
4. Human Vibration Measurement wit t e VM31...................................................7
4.1. Batteries.........................................................................................................7
4.2. Switc ing on and Connecting t e Sensor......................................................8
4.3. Hand-Arm Measurement wit t e VM31......................................................9
4.3.1. Measuring Points for Hand-Arm Vibration............................................9
4.3.2. VM31 Settings.....................................................................................10
4.4. W ole-Body Measurement wit t e VM31.................................................12
4.4.1. Measuring Points for W ole-Body Vibration......................................12
4.4.2. VM31 Settings.....................................................................................13
4.4.2.1. W ole-Body Measurement wit RMS Values..............................13
4.4.2.2. W ole-Body Vibration Measurement wit VDV Values..............18
4.4.2.3. Seat Effective Amplitude Transmissibility (SEAT)......................18
5. General Vibration Measurement.........................................................................19
6. Data Logger........................................................................................................21
7. Frequency Analysis............................................................................................22
8. Data Memory......................................................................................................23
8.1. Measurement Data Memory........................................................................23
8.2. Logger Data Memory..................................................................................23
8.3. FFT Data Memory.......................................................................................24
9. Keypad Lock......................................................................................................24
10. Device Settings.................................................................................................24
10.1. Sensor Calibration.....................................................................................24
10.2. Time and Date...........................................................................................24
10.3. S ut-off Timer...........................................................................................25
10.4. Battery Type..............................................................................................25
10.5. Display Brig tness....................................................................................25
10.6. Menu Language.........................................................................................25
10.7. Default Settings.........................................................................................26
11. Reset Key..........................................................................................................26
12. Connection to a PC...........................................................................................26
13. Data Transfer to a PC........................................................................................27
13.1. Opening t e Excel File vm31.xlsm...........................................................27
13.2. Data Import to Excel.................................................................................28
13.3. Calculation of Vibration Exposure A(8) and VDV(8)...............................28
13.4. FFT Data Import to Excel.........................................................................29
14. Firmware Update..............................................................................................30
15. Calibration........................................................................................................32
16. Tec nical Data..................................................................................................33
Appendix: Warranty
Declaration of CE Conformity
1

Thank you for choosing a Metra Vibration Measurement device!
1. Purpose
T e VM31 as been developed, particularly, for t e measurement and analysis of
uman vibration. Ot er fields of application include mac ine condition monitoring,
building vibration measurement and quality control.
In combination wit a triaxial accelerometer, and-arm and w ole-body vibrations
can be measured in compliance wit ISO 5349, ISO 2631 and t e EU Directive
2002/44/EC. A fourt measuring c annel can be used, for example, for SEAT mea-
surements (seat effective acceleration transmissibility).
T e VM31 meets t e requirements for uman vibration meters in compliance wit
ISO 8041. In t e development of t e VM31 value was placed on simple operation
and compact design.
In addition to its application as uman vibration meter t e VM31 can also measure
mac ine vibration according to ISO 10816-1/2/3/5/6/7. Measuring ranges for accel-
eration, velocity and displacement are available.
2. The Devi e at a Glan e
2
Figure 1: Controls, connectors and display

3. Fundamentals of Human Vibration Measurement
3.1. Introdu tion
Vibrations affecting t e uman body are called uman vibration. T e main purpose
of measuring uman vibration is t e prevention of ealt risks and t e evaluation of
comfort, for example in ve icles.
Two categories are distinguis ed:
•Hand-Arm Vibrations, w ic are induced via t e ands into t e body. T ey
may cause, for example, circulatory disorder, bone, joint or muscle diseases.
•Whole-Body Vibrations, acting via t e buttocks, t e back and t e feet of a sit-
ting person, t e feet of a standing person or t e back and t e ead of a recumbent
person. Suc vibrations may cause backac e or damage to t e spinal column.
Bot types of uman vibration measurement are described in international standards:
•ISO 5349 - Measurement and evaluation of uman exposure to and-transmitted
vibration
•ISO 631 - Evaluation of uman exposure to w ole-body vibration
(also ASA/ANSI S3.18)
•ISO 8041 - Human response to vibration. Measuring Instrumentation
•ISO 866 - Hand- eld portable power tools - Measurement of vibrations at t e
andle
•ISO 0 83-5 - Guidelines for t e measurement, reporting and evaluation of vi-
bration wit regard to abitability on passenger and merc ant s ips
•ISO 10056 - Measurement and analysis of w ole-body vibration to w ic pas-
sengers and crew are exposed in railway ve icles
•ISO 103 6 - Laboratory met od for evaluating ve icle seat vibration
•ISO 89 7 - Hand- eld portable power tools - Test met ods for evaluation of vi-
bration emission
Practical advice for measurement and evaluation of uman vibration can be found in
VDI 057.
T e subject of uman vibration as gained particular importance in Europe since t e
directive 00 /44/EC came into effect. It specifies t e duties of employers wit re-
gard to workers protection.
3

3.2. EU O upational Health Dire tive 2002/44/EC
T e following text is an abstract of Directive 2002/44/EC of t e European Parlia-
ment and of t e Council dated June 25, 2002. T e complete text can be downloaded
from ttp://eur-lex.europa.eu/
T e directive specifies minimum requirements for t e protection of workers from
t e risks arising from vibrations. Manufacturers of mac ines and employers s ould
make adjustments regarding risks related to exposure to vibration.
T e directive lays down t e following limit values:
Hand-Arm, RMS Whole-Body, RMS Whole-Body, VDV
Exposure action
value
2.5 m/s² 0.5 m/s² 9.1 m/s1,75
Exposure limit 5 m/s² 1.15 m/s² 21 m/s1,75
Table 1: Limits to EU directive 2002/44/EC
Once t e exposure action value is exceeded, t e employer s all establis and im-
plement a program of tec nical and organizational measures intended to reduce to a
minimum exposure to mec anical vibration, taking into account in particular:
•Ot er working met ods t at require less exposure to mec anical vibration
•Appropriate work equipment of ergonomic design, producing t e least possible
vibration
•Provision of auxiliary equipment t at reduces t e risk of injuries, suc as protec-
tive gloves or special seats
•Appropriate maintenance programs for work equipment
•Design and layout of workplaces
•Adequate information and training to instruct workers to use work equipment
correctly and safely
•Limitation of t e duration and intensity of t e exposure
•Work sc edules wit adequate rest periods
•Provision of clot ing to protect workers from cold and damp
In any event, workers s all not be exposed above t e exposure limit value. If t is
s ould be t e case, t e employer s all take immediate action to reduce exposure be-
low t e exposure limit value.
T e met ods used may include sampling, w ic must be representative of t e per-
sonal exposure of a worker to t e mec anical vibration in question.
T e assessment of t e level of exposure to vibration is based on t e calculation of
daily exposure A(8) expressed as equivalent continuous acceleration over an eig t-
our work period. For t e determination of A(8) it is not necessary to measure over
eig t ours. It is sufficient to make s ort-term measurements during representative
work steps. T e results are normalized to eig t ours. Daily exposure is calculated
as follows:
4

A(8)=awe
√
Te
T0
Equation 1
w ere
A(8) is t e daily exposure
awe is t e energy equivalent mean value of t e frequency weig ted acceleration
during exposure, w ic means
- For Hand-Arm Vibration t e X/Y/Z vector sum of W frequency-
weig ted RMS values (Equation 2)
aw=
√
awx
2+awy 2+awz 2
Equation 2
- For Whole-Body Vibration t e ig est of t e t ree RMS values
awx, awy and awz wit t e following frequency and magnitude weig tings:
- X and Y wit weig ting filter Wd and weig ting factor 1.4
- Z wit weig ting filter Wk and weig ting factor 1.0
Te is t e total duration of exposure during one work day
T0is t e reference duration of 8 ours
Daily exposure may consist of several partial exposures wit different vibration
magnitudes. T is can be t e case if t ere are longer interruptions in t e work
process, if t e work equipment or its way of use is c anged. A partial exposure sec-
tion s ould ave a roug ly constant magnitude and less t an 10 % interruptions. Re-
sulting daily exposure is calculated as follows:
Hand-Arm Vibration:
A(8)=
√
1
T0
∑
i=1
n
awi
2Tei
Equation 3
w ere
A(8) is t e daily exposure
awi is t e energy equivalent mean value of t e W frequency weig ted accelera-
tion of partial exposure section i
n is t e number of partial exposure sections
Tei is t e duration of exposure i
T0is t e reference duration of 8 ours
Whole-Body Vibration:
Separate daily exposures need to be calculated for X/Y/Z. T e ig est value is used
for t e evaluation, i.e. compared wit t e limits of Table 1.
Ax(8)=
√
1
T0
∑
i=1
n
awxi
2Tei
Equation 4
5

Ay(8)=
√
1
T0
∑
i=1
n
awyi
2Tei
Equation 5
Az(8)=
√
1
T0
∑
i=1
n
awzi
2Tei
Equation 6
w ere
Ax/y/z(8) are t e daily exposures of directions X/Y/Z
awx/y/zi are t e energy equivalent mean values of t e frequency weig ted accelerations
in t e directions X/Y/Z during partial exposure section i wit t e following
frequency and magnitude weig tings:
- X and Y wit weig ting filter Wd and weig ting factor 1.4
- Z wit weig ting filter Wk and weig ting factor 1.0
n is t e number of partial exposure sections
Tei is t e duration of exposure i
T0is t e reference duration of 8 ours
T e calculations s own above are based on RMS values. An alternative met od
uses fourt -power mean values called Vibration Dose Value (VDV) wit t e mea-
suring unit m/s1,75. Table 1 also includes VDV based limit values.
VDV based daily exposure VDV(8) is calculated:
VDV (8)=VDV⋅4
√
Texp
Tmeas
Equation 7
w ere
VDV(8) is t e daily exposure value
VDV is t e frequency-weig ted vibration dose value
Texp is t e duration of exposure
Tmeas is t e duration of VDV measurement
Daily exposure may consist again of several partial exposure sections. Separate
daily exposure values are to be calculated for X/Y/Z. T e ig est one is compared
wit t e limits of Table 1 for evaluation.
VDV x(8)= 4
√
∑
i=1
n
VDV xi
4⋅Tiexp
Timeas
Equation 8
VDV y(8)= 4
√
∑
i=1
n
VDV yi
4⋅Tiexp
Timeas
Equation 9
VDV z(8)= 4
√
∑
i=1
n
VDV zi
4⋅Tiexp
Timeas
Equation 10
w ere
6

VDVX/Y/Z(8) are t e daily exposures of directions X/Y/Z
VDVx/y/zi are t e frequency-weig ted vibration dose values of directions X/Y/Z dur-
ing exposure section i
Tiexp is t e duration of exposure section i
Tmeas is t e duration of VDV measurement during exposure section i
Model VM31 measures Hand-Arm and W ole-Body vibration, t e latter as RMS or
VDV values. For t e calculation of daily exposure an Excel s eet wit a data import
function is provided.
4. Human Vibration Measurement with the VM31
4.1. Batteries
T e VM31 is powered from t ree standard alkaline bat-
teries size AAA (LR03). Alternatively rec argeable
NiMH batteries of type HR03 can be inserted. Precise
operation is guaranteed until t e batteries are almost
completely disc arged.
Please note t at date and time need to be adjusted after
replacing t e batteries. All ot er settings, including
saved measurements, remain stored after removing t e
batteries.
To insert t e batteries, remove t e two screws from t e
back cover of t e device and open t e battery compart-
ment (Figure 2). W en inserting t e batteries, please en-
sure t at t eir polarity is correct, (see t e engraved
markings inside t e compartment).
Important:
•Always use t ree batteries of t e same type and same date of manufacture.
•Remove old batteries from t e device, and take out t e batteries if t e device will
not be used for a long period of time. Ot erwise leaking battery acid may cause
severe damage to t e device.
Please use your local collection point to dispose of batteries.
Batteries do not belong to t e ouse old waste.
A battery indicator can be found in t e upper left corner of t e display. A green
filled battery symbol indicates a fully c arged battery. W en t e symbol becomes
red only a small portion of power remains and t e unit will switc -off soon. Please
also read section 10.4.
If t e VM31 is connected to a USB interface, it will be powered via USB to save t e
batteries. In t is case “Extern” is s own instead of t e battery symbol.
7
Figure 2: Batteries

4.2. Swit hing on and Conne ting the Sensor
Switc on t e VM31 by pressing t e ON/OFF key. T e
unit can be switc ed off again by pressing and olding
t e ON/OFF key for one second.
If t e sensor as not yet been connected, plug t e sensor
cable into t e rig t connector. T e VM31 will start
TEDS1 detection eac time it is switc ed on or a sensor is
connected. It supports IEEE 1451.4 TEDS template no.
25 (wit or wit out transfer function). T e sensitivities of
X/Y/Z and c annel A are displayed for some seconds
(Figure 3). For eac c annel also t e user text of TEDS
(ID) is displayed.
T e sensors KB103SVD and KS903.10 supplied by Metra feature TEDS.
S ould a connected sensor not ave TEDS or an incompatible TEDS version, t e
VM31 will open a menu for entering t e sensitivities manually (see section 10.1).
T e sensitivities entered remain stored as long as t e sensor is connected, even if t e
batteries are removed.
T e warning “SENSOR!” indicates a missing or defective sensor or a broken sensor
cable. Sensor condition is detected by means of t e bias voltage at t e sensor out -
put:
< 0.7 V: s ort circuit
0,7 – 14 V: normal
>14 V: open, e.g. broken cable
Please note t at settling time after connecting a sensor is
about 1 minute.
T e VM31 is suitable for connecting any low power IEPE
accelerometers w ic can be operated wit a 1 mA supply
current. T e internal compliance voltage of t e current
sources is 18 VDC.
1 TEDS = Transducer Electronic Data S eet
8
Figure 3:
TEDS detection
Figure 4: Seat pad accelerometer KB103SVD
Figure 5:
Hand-Arm accelerometer KS903.10
Figure 6:
Sensor socket
(view from outside)
GND
XY
Z