Table of Contents
Summary of Contents for Manfred weber M208B
- Page 1 Instruction Manual 8 Channel IEPE Conditioner M208B Manfred Weber Metra Mess- und Frequenztechnik in Radebeul e.K. Meissner Str. 58 - D-01445 Radebeul Phone +49-351 836 2191 Fax +49-351 836 2940 Email: Info@MMF.de Internet: www.MMF.de...
- Page 2 The current version of this document can be downloaded from http://www.mmf.de/product_literature.htm Specifications subject to change without prior notice. © 2009 Manfred Weber Metra Mess- und Frequenztechnik in Radebeul e.K. No part of this document may be reproduced without the prior written consent of Metra. May/ 16...
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Page 3: Table Of Contents
Contents 1. Application......................4 2. The Instrument at a Glance..................4 2.1. Connectors and Controls................4 2.2. Menu Structure....................5 3. What is IEPE?......................5 4. Description of the Instrument ................7 5. Power Supply......................8 6. Inputs and IEPE Supply..................9 7. Outputs........................9 8. Grounding and Avoiding Ground Loops .............10 9. -
Page 4: Application
Thank you for using a vibration instrument from Metra! 1. Application The 8 Channel IEPE Conditioner M208B was designed for piezoelectric accelerom- eters, force transducers, pressure transducers and measuring microphones with IEPE output. The instrument has the following functions: • Constant current supply of up to eight sensors •... -
Page 5: Menu Structure
2/2: Gain calibration 3. What is IEPE? The M208B is a signal conditioner for sensors with IEPE output. The abbreviation stands for Integrated Electronics Piezo Electric and is a common industrial standard for the output of piezoelectric sensors and microphones. Proprietary brand names, like ICP ®... - Page 6 Sensor saturation voltage (approx. 1 V) negative overload Figure 3: Dynamic range of IEPE sensors The M208B features a circuit for sensor check. It can detect the following condi- tions, based on the sensor output voltage: • No sensor: yellow LED off •...
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Page 7: Description Of The Instrument
20dB Figure 4: Block diagram The sensor signals enter the M208B via BNC sockets on the front panel. The IEPE constant current sources may be switched off individually. The input is followed by an amplifier stage with selectable gains of 0 or 20 dB. High pass and low pass filters are designed as plug-in modules. -
Page 8: Power Supply
5. Power Supply The M208B is powered by an external DC supply voltage between 10 and 28 V. This could be a supplied mains adapter or a car battery, for example. Current con- sumption is below 1.5 A. The supply voltage is connected by a circular power con- nector to DIN 45323. -
Page 9: Inputs And Iepe Supply
For the operation with IEPE sensors constant current sources must be switched to the inputs (see 10.5 on page 17). By default the M208B is equipped with 4 mA con- stant current sources which is a practical value for most applications. For extremely long sensor cables and high frequencies to be measured, the instrument can also be equipped with 8 mA sensor supplies. -
Page 10: Grounding And Avoiding Ground Loops
Figure 8: Gain selection After switching it on, the M208B displays the gain menu (Figure 8). The selected gain ranges are shown over the respective channel numbers. The flash- ing value can be changed by the ▲▼ keys. You may select between 0, 20, 40 and 60 dB. -
Page 11: Filters And Integrators
0 dB range the signal may become clipped even if no overload is indi - cated. 10. Filters and Integrators 10.1. Filters The M208B has replaceable high pass and low pass filter modules. The following frequencies are available: High pass filters: Low pass filters:... - Page 12 HP off FB3-3 FB3-5 FB3-10 FB3-30 FB3-50 FB3-100 FB3-300 FB3-500 FB3-1000 0,01 1000 10000 f [Hz] Figure 9: Frequency response of M208B with different high pass filters FB3-... FB2-0,1 FB2-0,3 FB2-0,5 FB2-1 FB2-3 FB2-5 FB2-10 FB2-30 FB2-50 FB2-100 1000 10000 100000...
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Page 13: Integrators
HP aus FB3-3Hz FB3-5Hz FB3-10Hz FB3-30Hz FB3-50Hz FB3-100Hz FB3-300Hz FB3-500Hz FB3-1000Hz 1000 10000 f [Hz] Figure 11: Phase response of M208B with different high pass filters FB3-... FB2-0,1 FB2-0,3 FB2-0,5 FB2-1 FB2-3 FB2-5 FB2-10 FB2-30 FB2-50 -100 FB2-100kHz -120 -140... - Page 14 The calculations show how the M208B output u corresponds to the three vibra- tion quantities. The selected gain range of the M208B is G (1, 10, 100 or 1000) and the accelerometer sensitivity (see transducer data sheet) is B...
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Page 15: Replacing Filter Modules
Example: Vibration velocity is measured using an accelerometer with a sensitivity of B = 5 mV/ms The M208B is operated in the range G = 100. Its output voltage is 300 mV . What is the corresponding vibration velocity? Solution: 300 mV ⋅10 s=6 mm /s... -
Page 16: Switching Off The High Pass Filters
When inserting the filter or integrator, make sure that the “Pin 1” mark (▼) faces to the correct side. For proper function of the M208B it is necessary that all filters or integrators are in- serted. Figure 15: Location of the filter and integrator modules 10.4. -
Page 17: Switching The Iepe Supply On Or Off
10.6. Loading Default Settings The M208B can be reset to its factory default settings in the menu “3/4: Load de- faults”. The following settings will be changed: • Gain for all channels 0 dB •... -
Page 18: Hardware And Software Version
(“Gain range”, 0/20/40/60 dB) by the ▲▼keys. Feed in the generator signal accord- ing to the display of the M208B, for example 50.00 mV in the gain range 40 dB. The M208B will display the previously entered calibration value in percent, for ex- ample “-0.3%”. -
Page 19: Technical Data
13. Technical Data Inputs 8 voltage inputs; single-ended; R = 4 M AC coupled; IEPE compatible; BNC sockets ± 10 V without clipping at 0 dB gain ± 25 V peak input voltage IEPE sensor supply 3.8 to 5.6 mA constant current; switchable compliance voltage >... -
Page 20: Limited Warranty
Declaration of Conformity According to EMC Directive 2014/30/EC Product: 8 Channel IEPE Conditioner Type: M208B (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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