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MMF VM31 Instruction Manual

Human-vibration analyzer
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Instruction Manual
Human-
Vibration
Analyzer
VM31
(Valid from version xxx.016)
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 xxx.016) 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

    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

    (seat effective acceleration transmissibility). The VM31 meets the requirements for human vibration meters in compliance with ISO 8041. In the development of the VM31 value was placed on simple operation and compact design. In addition to its application as human vibration meter the VM31 can also measure machine vibration according to ISO 10816-1/2/3/5/6/7.

  • 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

    Please also read section 10.4. If the VM31 is connected to a USB interface, it will be powered via USB to save the batteries. In this case “Extern” is shown instead of the battery symbol.

  • Page 10: Switching On And Connecting The Sensor

    Should a connected sensor not have TEDS or an incompatible TEDS version, the VM31 will open a menu for entering the sensitivities manually (see section 10.1). The sensitivities entered remain stored as long as the sensor is connected, even if the batteries are removed.

  • 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

    Value, MTVV) which may indicate the pres- ence of shock vibration. The frequency weighting for hand-arm vibration is Wh. Figure 11 shows the filter of the VM31 and the toler- ance bands to ISO 5349. Figure 10: Hand-arm measurement...
  • Page 13 (see section 3.2). For the calculation of vibration exposure A(8) and to store results on a PC the Ex- cel macro file vm31.xlsm is provided. The fourth channel (A) of the VM31 is not active when hand-arm vibration is mea- sured.

  • Page 14: Whole-Body Measurement With The Vm31

    4.4. Whole-Body Measurement with the VM31 This section will give you basic instructions for the measurement and evaluation of whole-body vibrations based on the standard ISO 2631 and the guideline VDI 2057, Part 1. Please consult the original documents for detailed explanations.

  • Page 15: Vm31 Settings

    Z perpendicularly to the backbone. However, to compensate this the VM31 auto- matically swaps the X and Z axis for backrest measurement.
  • Page 16 1.0 for Z. Figures 15 and 16 show the frequency response curves of the filters Wd and Wk in VM31 and the tolerance bands in compliance with ISO 8041. Wd min ISO 8041 Wd max ISO 8041 Wd VM31...
  • Page 17 Wb min ISO 8041 Wb max ISO 8041 Wb VM31 0,01 0,001 0,0001 1000 Figure 17: Whole-body weighting filter Wb for passenger trains Wc min ISO 8041 Wc max ISO 8041 Wc VM31 0,01 0,001 0,0001 1000 Figure 18: Whole-body weighting filter Wc for the backrest of seats...
  • Page 18 Wj min ISO 8041 Wj max ISO 8041 Wj VM31 0,01 0,001 0,0001 1000 Figure 19: Whole-body weighting filter Wj for the head of recumbent persons Wm min ISO 8041 Wm max ISO 8041 Wm VM31 0,01 0,001 0,0001 1000...
  • Page 19 Measurements can only be saved if a sensor is detected at X/Y/Z and if there is no overload condition. In these cases the VM31 will display “Sensor error” or “Over- load occurred” instead of saving in order to avoid invalid recordings. If an overload occurred since the last reset (“OVL!”...

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

    4.4.2.2. Whole-Body Vibration Measurement with VDV Values The VM31 also allows whole-body vibration to be measured as vibration dose val- ues (VDV). These are integrated fourth power values. VDV is more sensitive to peaks. The measuring unit of VDV is m/s 1,75 √...

  • Page 21: General Vibration Measurement

    SEAT values. Metra recommends the TEDS accelerometer KS78.100 for this purpose. It is connected via a sensor cable VM31-A to the left socket (see 1). The fourth channel is named “A” on the display. The sensitivity of the KS78.100 will be automatically detected.
  • Page 22 Vibration velocity is computed by single integration of the acceleration signal, displace- ment by double integration. Due to integration there is a strong attenuation at high fre- quencies which limits the measurable frequencies, particularly for displacement. Low frequencies, including noise, are strongly amplified. High pass filtering is inevitable. The frequency response curves of the general vibration ranges can be seen in Figures 27, 28 and 29.

  • Page 23: Data Logger

    • restarts the measuring timer. Measurements can be saved by pressing the key ▼ (see page 17). The Excel file vm31.xlsm can be used to transfer the measurements to a PC. 6. Data Logger The VM31 can automatically record measuring data for channels X/Y/Z at the speed of the display re- fresh rate.

  • Page 24: Frequency Analysis

    The maximum number of records per log file is 32,000 which is sufficient for about 10 hours of continuous recording. 7. Frequency Analysis The VM31 provides a simple FFT function for the detection of main frequencies. It displays a 125 line peak spectrum of acceleration. Press F3 and select “Frequency analysis” to open the FFT screen (Figure 32).

  • Page 25: 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,...

  • Page 26: Fft Data Memory

    FFT. A cursor function using the keys ◄► is also available (Figure 36). Stored FFT data can be transferred to a PC using the Excel macro file vm31.xlsm. The file also provides a graphical output. 9. Keypad Lock To prevent manipulation during ongoing mea-...

  • Page 27: Shut-Off Timer

    The sign changes to minus at +254 ppm. 10.3. Shut-off Timer The VM31 has a shut-off timer to help prolong the battery operating life. To set the shut-off timer, open the main menu by pressing F3, select “Device set- tings”...

  • Page 28: Default Settings

    12. Connection to a PC The VM31 has a USB interface. The VM2x-USB cable (Figure 44) is connected to the VM31 via its 8 pin connector. Switch the device off before connecting it to the Figure 44: USB cable VM2x-USB Connect the other end of the cable to a USB port on the computer and switch the VM31 on again.

  • Page 29: Data Transfer To A Pc

    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 30: Data Import To Excel

    “Clear tables” to erase all measurements from the tables. Connect the VM31 to a USB port on the PC and switch it on. If not done before, install the device driver (section 12). Click “Import measurements from VM31”.

  • Page 31: Fft Data Import To Excel

    Figure 48: Example report (part) 13.4. FFT Data Import to Excel The FFT data stored on the VM31 can also be transferred to the Excel macro file. Switch to the worksheet “FFT Import”. If previous FFT data is appears in the table, please save the file under another name and click “Clear FFTs”...

  • Page 32: Firmware Update

    2. Also download the program “Firmware Updater” from the above named internet address and install it on your PC. 3. Connect the VM31 to the PC using the USB cable and switch it on so that Win- dows can detect it as a USB device and assign a COM port.
  • Page 33 6. In the VM31 “Device Settings” select the option “Firmware update” and con- firm the warning and subsequent hint messages by pressing OK. By carrying out this step the old firmware is deleted. The VM31 will then indicate that it awaits new firmware data from the USB interface (Figure 52).

  • Page 34: 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 50).

  • Page 35: 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 36: Declaration Of Ce Conformity

    Declaration of Conformity According to EMC Directive 2014/30/EC Product: Triaxial Vibration Meter Type: VM31 (from Ser. no. 160000) It is hereby certified that the above mentioned product complies with the demands pursuant to the following standards: DIN EN 61326-1: 2013...

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