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MMF VM31-M Instruction Manual

Human vibration analyzer
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Instruction Manual
Human-
Vibration
Analyzer
VM31
(Valid from version 003.023)
Manfred Weber
Metra Mess- und Frequenztechnik in Radebeul e.K.
Meissner Str. 58 - D-01445 Radebeul
Tel. +49-351 836 2191 Fax +49-351 836 2940
Email:
Info@MMF.de
Internet:
www.MMF.de

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  • Page 1 Instruction Manual Human- Vibration Analyzer VM31 (Valid from version 003.023) Manfred Weber Metra Mess- und Frequenztechnik in Radebeul e.K. Meissner Str. 58 - D-01445 Radebeul Tel. +49-351 836 2191 Fax +49-351 836 2940 Email: Info@MMF.de Internet: www.MMF.de...
  • Page 2 Manfred Weber Metra Mess- und Frequenztechnik in Radebeul e.K. Meißner Str. 58 D-01445 Radebeul Tel. +49-351-836 2191 +49-351-836 2940 Email Info@MMF.de Internet www.MMF.de Note: The latest version of this manual can be found at http://www.mmf.de/prod- uct_literature.htm Specification subject to change.

  • Page 3: Table Of Contents

    Contents 1. Purpose.........................2 2. The Device at a Glance..................2 3. Fundamentals of Human Vibration Measurement..........3 3.1. Introduction....................3 3.2. EU Occupational Health Directive 2002/44/EC..........4 4. Human Vibration Measurement with the VM31...........7 4.1. Batteries......................7 4.2. Switching on and Connecting the Sensor............8 4.3. Hand-Arm Measurement with the VM31............9 4.3.1.

  • Page 4: Purpose

    Thank you for choosing a Metra Vibration Measurement device! 1. Purpose The VM31 has been developed, particularly, for the measurement and analysis of human vibration. Other fields of application include machine condition monitoring, building vibration measurement and quality control. In combination with a triaxial accelerometer, hand-arm and whole-body vibrations can be measured in compliance with ISO 5349, ISO 2631 and the EU Directive 2002/44/EC.

  • Page 5: Fundamentals Of Human Vibration Measurement

    3. Fundamentals of Human Vibration Measurement 3.1. Introduction Vibrations affecting the human body are called human vibration. The main purpose of measuring human vibration is the prevention of health risks and the evaluation of comfort, for example in vehicles. Two categories are distinguished: •...

  • Page 6: Eu Occupational Health Directive 2002/44/Ec

    3.2. EU Occupational Health Directive 2002/44/EC The following text is an abstract of Directive 2002/44/EC of the European Parlia - ment and of the Council dated June 25, 2002. The complete text can be downloaded from http://eur-lex.europa.eu/ The directive specifies minimum requirements for the protection of workers from the risks arising from vibrations.
  • Page 7 √ A(8)=a Equation 1 where A(8) is the daily exposure is the energy equivalent mean value of the frequency weighted acceleration during exposure, which means - For Hand-Arm Vibration the X/Y/Z vector sum of Wh frequency- weighted RMS values (Equation 2) √...
  • Page 8 √ ∑ (8)= Equation 5 √ ∑ (8)= Equation 6 where are the daily exposures of directions X/Y/Z x/y/z are the energy equivalent mean values of the frequency weighted accelerations wx/y/zi in the directions X/Y/Z during partial exposure section i with the following frequency and magnitude weightings: - X and Y with weighting filter Wd and weighting factor 1.4 - Z with weighting filter Wk and weighting factor 1.0...

  • Page 9: Human Vibration Measurement With The Vm31

    (8) are the daily exposures of directions X/Y/Z X/Y/Z are the frequency-weighted vibration dose values of directions X/Y/Z dur- x/y/zi ing exposure section i is the duration of exposure section i iexp is the duration of VDV measurement during exposure section i meas Model VM31 measures Hand-Arm and Whole-Body vibration, the latter as RMS or VDV values.

  • Page 10: Switching On And Connecting The Sensor

    4.2. Switching on and Connecting the Sensor Switch on the VM31 by pressing the ON/OFF key. The unit can be switched off again by pressing and holding the ON/OFF key for one second. If the sensor has not yet been connected, plug the sensor cable into the right connector.

  • Page 11: Hand-Arm Measurement With The Vm31

    Figure 6 shows the contact arrangement of the 4 pin female sensor connector of type Binder 711. 4.3. Hand-Arm Measurement with the VM31 This section will give you basic instructions for the measurement and evaluation of hand-arm vibrations based on the standard ISO 5349 and the guideline VDI 2057, Part 2.

  • Page 12: Vm31 Settings

    4.3.2. VM31 Settings For the evaluation of hand-arm vibration it is recom- mended to measure both the interval RMS values of X/Y/Z and their vector sum a . The VM31 measures these four values simultaneously. In addition it shows the maximum running RMS (Maximum Transient Vi- bration Value, MTVV) which may indicate the pres- ence of shock vibration.
  • Page 13 The VM31 supports in addition measurements with frequency weighting W accord- ing to ISO/TR 18570 (Figure 12). It was developed for assessing the risk of vascular diseases (vibration white finger). However, there are no mandatory limit values yet for this type of measurement. Wp min ISO Wp max ISO Wp VM31...

  • Page 14: Whole-Body Measurement With The Vm31

    After measurement you may save the results by pressing the key ▼. Measurement should be contin- ued or finished immediately before pressing the key. Otherwise the measuring values will drop slowly. You will be asked to enter two lines of ten capital let- ters or numbers as a comment (Figure 13).
  • Page 15 column. The vibration sensor has to be placed accordingly. A special case is mea- surement at the backrest (see notice below Table 2 on page 13). Figure 14: Coordinate systems for whole-body vibration to ISO 2631 Table 2 shows the weighting filters and factors to be used for different postures and positions.

  • Page 16: Vm31 Settings

    * Please note that the Z axis points along the backbone for all measurements. For measure - ments at the backrest with a seat pad accelerometer the sensor will always be in a vertical po- sition with Z perpendicularly to the backbone. However, to compensate this the VM31 auto- matically swaps the X and Z axis for backrest measurement.
  • Page 17 Wk min ISO 8041 Wk max ISO 8041 Wk VM31 0,01 0,001 0,0001 1000 Figure 17: Whole-body weighting filter Wk In addition to health evaluation the VM31 also supports measurements regarding comfort. This type of measurement uses other postures, sensor positions and differ- ent frequency weightings but the general procedure is the same.
  • Page 18 Wc min ISO 8041 Wc max ISO 8041 Wc VM31 0,01 0,001 0,0001 1000 Figure 19: Whole-body weighting filter Wc for the backrest of seats Wj min ISO 8041 Wj max ISO 8041 Wj VM31 0,01 0,001 0,0001 1000 Figure 20: Whole-body weighting filter Wj for the head of recumbent persons...
  • Page 19 Wm min ISO 8041 Wm max ISO 8041 Wm VM31 0,01 0,001 0,0001 1000 Figure 21: Whole-body weighting filter Wm for persons in buildings To start whole-body vibration measurement for the assessment of health risks open the main menu by pressing F3, and select “Measuring mode” / “Human vibration” / “Whole-body ISO 2631”...

  • Page 20: Whole-Body Vibration Measurement With Vdv Values

    vibration is at least 2 minutes. To alert you, the timer in the upper right corner re - mains red until 2 minutes have elapsed. The displayed interval RMS for X/Y/Z and vibration total values a include the weighting factors (k) according to table 2. The weighting factors are set to 1 for maximum RMS (MTVV) and vibration dose value (VDV).

  • Page 21: Seat Effective Amplitude Transmissibility (Seat)

    Measurements can be saved by pressing the key ▼ (see page 18). For vibration exposure VDV(8) calculation the duration of VDV measurement should be noted (see section 3.2.). The Excel file vm31.xlsm also allows the calculation of vibration exposure VDV(8) (see section 13.3.). 4.4.2.3.
  • Page 22 You can switch the measuring screen from RMS to peak display by pressing the key ◄. Please note that the RMS and peak values in the general vibration ranges are measured over the last display cycle (not over a long pe- riod).
  • Page 23 a: 1Hz – 1kHz a: 0,1 Hz – 2 kHz 0,01 1000 10000 Figure 28: Frequency ranges of vibration acceleration 0,01 v: 1Hz – 100Hz v: 2Hz – 1kHz v: 10Hz – 1kHz* 0,001 0,0001 1000 10000 Figure 29: Frequency ranges of vibration velocity...

  • Page 24: Data Logger

    0,01 0,001 0,0001 1000 Figure 30: Frequency range of vibration displacement (upper end due to resolution) Vibration quantity and frequency range can be checked by pressing F1. Below the 3 (or 4) RMS or peak values you can see two combined values which are calculated from X/Y/Z.

  • Page 25: Frequency Analysis

    are filtered with the same weighting or band filter used for the displayed measure- ments. Channel A is not recorded. Please note that the logged data is calculated only for the last display interval (ap - prox. 1 s). For human vibration, however, interval RMS values are measured which are integrated over the entire measuring time.

  • Page 26: Data Memory

    8. Data Memory 8.1. Measurement Data Memory The VM31 memory can hold up to 10,000 data records. A record includes: • Date and time • Comment (20 characters) • Filter and measuring mode • Measuring values X/Y/Z and, if available, channel A and 2 combined values (vector sum and maximum value) Saved data can be viewed on the screen.

  • Page 27: Fft Data Memory

    8.3. FFT Data Memory To view stored FFTs press F3 to open the menu and select “Data memory” / “View/delete FFT data”. Use the keys ▲▼ to select the desired FFT. A cursor function using the keys ◄► is also available (Figure 37). Stored FFT data can be transferred to a PC using the Excel macro file vm31.xlsm.

  • Page 28: Shut-Off Timer

    Additionally, clock inaccuracy can be corrected. This can be done using the setting at “Cal.” in ppm (parts per million). The clock frequency can be increased with pos - itive values and decreased with negative. The sign changes to minus at +254 ppm. 10.3.

  • Page 29: Default Settings

    The driver MMF_VCP.zip can be found on our website: http://mmf.de/software_download.htm Unpack and save both driver files in a directory on your computer. When Windows requests details of the source of the device driver, this directory...

  • Page 30: Data Transfer To A Pc

    The Excel macro file vm31.xlsm is provided to transfer, display and archive data from the VM31. It can be downloaded from http://www.mmf.de/software_down- load.htm. The file runs with all Excel versions starting from Excel 2007. It transfers the stored data from the connected VM31 memory into Excel tables. Vi - bration exposure A(8) or VDV(8) can be calculated from the human vibration records and measuring reports can be generated.

  • Page 31: Data Import To Excel

    13.2. Data Import to Excel Open the worksheet “Import”. If previous measurement data appears in the table, please save the file under another name and then click “Clear tables” to erase all measurements from the tables. Connect the VM31 to a USB port on the PC and switch it on.

  • Page 32: Fft Data Import To Excel

    Figure 48: Daily exposure calculation in Excel Click “A(8) calculation” or, in the case of VDV, “Daily exposure calculation” to calculate the vibration exposure (Figure 48). The result(s) will be compared with the limits stated in the EU directive 2002/44/EC and are displayed in various colors: black: below exposure action value purple:...

  • Page 33: Firmware Update

    To view the latest version visit our 'Software Download' site. http://www.mmf.de/software_download.htm Here you will see the most recent firmware version available. The version number is composed of three digits for the hardware and three for the software (hh- h.sss).
  • Page 34 Figure 52: Firmware Updater 5. Click on “Load” in the “Firmware Updater” and enter the path to the file where the downloaded firmware file vm31.hex is located. 6. In the VM31 “Device Settings” select the option “Firmware update” and con- firm the warning and subsequent hint messages by pressing OK.

  • Page 35: Calibration

    15. Calibration The VM31 is supplied with a factory calibration. In this way it is assured that the in - strument measures accurately if a calibrated transducer is connected and its sensitiv- ity entered (see section 10.1.). Month and year of the last calibration are shown on the start screen (Figure 51).

  • Page 36: Technical Data

    16. Technical Data Inputs 4 Low-power IEPE inputs, 1 mA / 17 V, transducer sensitivity range 0.8 to 120 mV/ms TEDS support for template 25 to IEEE 1451.4 Display functions Interval RMS Human vibration Vector sum Maximum running RMS (MTVV) Vibration dose value (VDV) Crest factor (whole body only) General vibration...

  • Page 37: Declaration Of Ce Conformity

    Limited Warranty Metra warrants for a period of 24 months that its products will be free from defects in material or workmanship and shall conform to the specifications current at the time of shipment. The warranty period starts with the date of invoice. The customer must provide the dated bill of sale as evidence.

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