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Summary of Contents for MMF M208A
- Page 1 Instruction Manual 8 Channel IEPE Conditioner M208A From Version 001.012 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 Metra Mess- und Frequenztechnik in Radebeul e.K. Meissner Str. 58 D-01445 Radebeul Phone +49-351-836 2191 +49-351-836 2940 Email Info@MMF.de Internet www.MMF.de Notice: The current version of this document can be downloaded from http://www.mmf.de/product_literature.htm Specifications subject to change without prior notice.
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Page 3: Table Of Contents
Contents 1. Application......................5 2. The Instrument at a Glance..................5 2.1. Connectors and Controls................5 2.2. Display Functions...................6 2.3. Menu Structure....................6 3. What is IEPE?......................7 4. What is TEDS?......................8 5. Description......................11 6. Power Supply......................12 7. Inputs and IEPE Supply..................12 8. Outputs........................13 9. Grounding and Avoiding Ground Loops ............14 10. - Page 4 12.6. Loading Default Settings................32 12.7. Overload Limits..................33 12.8. Firmware Update..................34 13. PC Connection....................35 13.1. Serial Interface...................35 13.1.1. Settings....................35 13.1.2. Linking Several M208A Units............35 13.1.3. PC Software M208 Control Center.............36 13.1.3.1. Introduction.................36 13.1.3.2. System Requirements..............36 13.1.3.3. Controls and Functions..............37 13.1.3.3.1 Device Menu.................38 13.1.3.3.2 Device Channels..............40...
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Page 5: Application
• Normalization of transducer sensitivity • High pass and low pass filtering, optionally single and double integration In addition, the M208A can display RMS or peak values including physical units. A relay output is available for controlling external devices. The M208A features a serial interface for setup and readout by a supplied PC software. -
Page 6: Display Functions
2.2. Display Functions Transducer sensitivity Physical unit Displayed channel Display mode RMS Rel. magnitude Press OK to stop Measuring value channel rotation Relay output High pass and low pass filter Display mode Peak Rel. magnitude below 5 % of full scale Press OK for channel rotation Figure 2: Display in measuring mode 2.3. -
Page 7: What Is Iepe
3. What is IEPE? The M208A 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 8: What Is Teds
Figure 4: Dynamic range of IEPE sensors The M208A features a circuit for sensor check. It can detect the following condi- tions, based on the sensor output voltage: • No sensor present (yellow LED off, no measuring value for this channel) •... - Page 9 In addition there are proprietary manufacturer templates. The M208A supports the standard template no. 25 for piezoelectric accelerometers and force transducers and the template nos. 27 and 28 for measuring microphones. These templates allow the specification with or without a transfer function by means...
- Page 10 Template No. 25 for piezoelectric accelerometers and force transducers: Without transfer function: With transfer function: • Sensitivity • Sensitivity • Lower frequency limit • Lower frequency limit • Measuring direction • Measuring direction • Weight • Weight • Polarity • Polarity •...
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Page 11: Description
-20..0dB Figure 6: Block diagram The sensor signals enter the M208A 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 12: Power Supply
For the operation with IEPE sensors constant current sources must be switched to the inputs (see 12.4 on page 31). By default the M208A 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 13: Outputs
The shared output is always switched to the channel which is currently measured. The M208A performs multiplex measurement with an interval of 1 s. Multiplexing may be stopped at a desired channel by pressing the OK key. Then the selected channel is permanently connected to the shared output. -
Page 14: Operation
M208A, to a physical unit. The actual gain of the M208A will not be 0, 20, 40 or 60 dB but an odd value providing a rela- tion between output voltage and measured physical quantity in multiples of ten. - Page 15 Normalization is done by entering transducer sensitivity in millivolts per mechani - cal unit. Permissible values are between 1 and 12. At a sensitivity of 1 the M208A works with its basic gain ranges of 0, 20, 40 and 60 dB (1, 10, 100 and 1000) see section 10.1).
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Page 16: Normalization Of The Display
10.2.2. Normalization of the Display The following table shows the full scale values for different transducer sensitivities and gain ranges for the example of an accelerometer in m/s². 0 dB 20 dB 40 dB 60 dB 0.1 .. 100.0 .. 10.00 km/s²... -
Page 17: Sensor Detection
Deactivation of unused channels is recommended to avoid interference (section 10.3 on page 19). When the M208A detects the connection of a new sensor, it will show the message “New sensor detected” and ask the user to enter the sensitivity. Sensitivity is entered with five digits and a decimal point in millivolts per mechanical unit. -
Page 18: Entering Transducer Sensitivity In The Menu
Figure 13: Entering transducer sensitiv- 10.2.6. Automatic Sensitivity Adjustment with TEDS Sensors The M208A will automatically detect the connection of a TEDS sensor (see section 4 on page 8) and read out its sensitivity. It will prompt “TEDS Sensor at Ch..”, show TEDS version, template number, model number and, if applicable, the direc- tion (X/Y/Z). -
Page 19: Channel Registration
Figure 15: TEDS sensitivity display If the sensitivity stored in the TEDS memory should exceed the permissible limits of the M208A (0.1 to 12000 mV/mech. unit), an error message “TEDS sensitivity out of range” will appear. Any other parameters stored in the TEDS memory (see section 4 on page 8) will not be used by the M208A. -
Page 20: Measuring Unit
10, 100 or 1000). 10.5. Display Mode The M208A can display the amplifier output as true RMS or peak values. Measur- ing time is 1 s per channel. Open the menu “3/6: Display mode” to choose between the two modes and press OK to confirm. -
Page 21: Measuring Display
10.6. Measuring Display The measuring display is the normal operation mode of the M208A. Measuring val- ues are displayed in rotation for the active channels, i.e. if a channel was activated (section 10.3 on page 19) and a sensor was detected at the respective input (section 10.2.4 on page 17). -
Page 22: Relay Output
(section 10.8). 10.8. Relay Output The relay output of the M208A can control external alarm devices. It has a potential free change-over contact which is connected to the 25 pin Sub-D socket on the rear panel. 23 shows the pin assignment for alarm condition. - Page 23 Use the keys ▲▼◄ ► to deactivate (○) or activate (●) the channels for relay con- trol. In the subsequent menu you will be asked to enter a trip limit for each activated channel. Figure 25: Entering relay trip limits Numbers are entered by the keys ▲▼.
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Page 24: Filters And Integrators
11. Filters and Integrators 11.1. Filters The M208A has replaceable high pass and low pass filter modules. The following frequencies are available: High pass filters: Low pass filters: 3 dB frequency limit Model 3 dB frequency limit Model 3 Hz FB3-3Hz 0.1 kHz... - Page 25 FB2-0,5 FB2-1 FB2-3 FB2-5 FB2-10 FB2-30 FB2-50 FB2-100 1000 10000 100000 1000000 f [Hz] Figure 28: Frequency response of M208A with different low pass filters FB2-... HP aus FB3-3Hz FB3-5Hz FB3-10Hz FB3-30Hz FB3-50Hz FB3-100Hz FB3-300Hz FB3-500Hz FB3-1000Hz 1000 10000 f [Hz]...
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Page 26: Integrators
10000 100000 1000000 f [Hz] Figure 30: Phase response of M208A with different low pass filters FB2-... 11.2. Integrators Integrators are useful to calculate vibration velocity or displacement from an accel- eration input. Single or double integrator modules can be plugged in instead of filters. Mixed filter operation is also allowed. - Page 27 The calculations show how the M208A output u corresponds to the three vibra- tion quantities. The selected gain range of the M208A is G (1, 10, 100 or 1000) and the accelerometer sensitivity (see transducer data sheet) is B...
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Page 28: Replacing Filter And Integrator Modules
Example: Vibration velocity is measured using an accelerometer with a sensitivity of B = 5 mV/ms . The M208A is operated in the range G = 100. Its output voltage is 300 mV . What is the corresponding vibration velocity? -
Page 29: Detection And Display Of Filters And Integrators
“Pin 1” mark (▼) faces to the cor- rect side. For proper function of the M208A it is necessary that all filters or integrators are in - serted. Figure 33: Location of the filter and integrator modules 11.4. -
Page 30: Switching Off The High Pass Filters
11.5. Switching Off the High Pass Filters The high pass filters can be switched off separately for each channel. The M208A will then work with its lower frequency limit of approximately 0.1 Hz. Press the MENU key, select “1/6: Filter setup” and the sub-menu “2/2: Highpass on/off”. -
Page 31: Ethernet Interface
19). 12.5. Instrument Name You may give your M208A a name of up to 20 characters length. It may give infor- mation about its location or the test object, for example. This name will appear after pressing the key ◄ in measuring mode, in the headline of the HTML page hosted... -
Page 32: Instrument Name
• IP address 192.168.181.30, subnet 255.255.255.0, Ethernet off 12.7. Overload Limits The M208A signal path has a dynamic range of ± 10 V. At 90 % of this magnitude the display and the red LEDs will indicate overload accompanied by a beep sound (see section 12.1 on page 30 for deactivation). - Page 33 reach this magnitude. The dynamic range can be found in the transducer data sheet. Therefore it is useful to enter a lower input overload limit. This is done in the same way as for the outputs. Figure 39: Input overload limit ...
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Page 34: Firmware Update
M208A will be waiting for data from the serial interface. Click the “Send” button in the firmware updater utility. The update takes two to three minutes. Progress is indicated at the M208A by the LEDs flashing up in inter - vals of eight seconds. -
Page 35: Pc Connection
13.1.2. Linking Several M208A Units Up to eight M208A units can be controlled by one serial interface. The units are in- terconnected using a “daisy chain” network. The first unit in the chain is connected to the PC via its “MASTER”... -
Page 36: Pc Software M208 Control Center
• Internet access (for installing required software components) • RS-232 interface or RS-232 / USB adapter • One to eight daisy-chained M208A instruments. Operation via separate serial in - terfaces is not supported. The software communicates only via one selectable in- terface with the M208A units. -
Page 37: Controls And Functions
Clicking Exit will save all settings and close the program. 2. Device Tree This section shows all connected M208A units and their channels. A mouse click on an M208 entry or a channel will open the respective setup window. 3. Tab controlled menus with device and channel settings and optional modules as described in the following chapters. -
Page 38: Device Menu
Device Menu 13.1.3.3.1 44 shows the menu for general settings of the M208A. Figure 44: Device menu It is divided into the action menu (A), the device settings (B) and a table with present devices (C). Menu Actions Figure 45: Actions... - Page 39 The interface settings are equal for all units in a chain. 9. Serial Number This is the serial number of the M208A being displayed. You can click on the entry to switch to another unit.
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Page 40: Device Channels
10. Name The name of the active M208A is displayed. Click on the entry to change the name (up to 20 characters, capital letters A to Z, numbers 0 to 9 and space). 11. Internal Temperature Temperature measured inside of the M208A case. The background will change its color if a temperature limit was exceeded (see settings, section 13.1.3.3.4). - Page 41 The channel number is displayed in the form XX – CHY, where XX is a consecu - tive number of all available channels from 01 to 64 and Y is the channel number of the selected M208A, i.e. 1 to 8. The channel number cannot be edited. 2. Filter Here the frequency range of the plugged in high pass and low pass modules or sin- gle / double integrators appears.
- Page 42 3. Measuring Display This is the RMS or peak measuring value calculated by the M208A. The value is held till the next refresh. The refresh rate can be changed in the File / Settings menu. Please note that the M208A provides only one measuring value per second. So mea - suring all eight channels will take eight seconds.
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Page 43: Channel Overview
10. IEPE Supply The constant current supply for the sensor can be switched off here. With IEPE supply switched off the display unit automatically becomes Volt. 11. Alarm Here you may connect the alarm relay to the respective channel. If the measuring value exceeds the entered trip level, the relay will switch to alarm position. -
Page 44: Other Menus
At program start the settings are loaded either from a *.ini file or via RS-232 from the M208A. Loading from a file assumes that no changes have been made at the M208A in the meantime. If you are not sure, reload the settings. This may take, however, up to 30 seconds. - Page 45 • TEDS-Editor: Optional module for editing TEDS sensors. 8. Activated devices Each license key is for one to eight M208A units which can be found in this field. A license is valid for a maximum of eight units. It is also possible to use these eight units with up to eight different computers simultaneously.
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Page 46: Function Keys
• Invalid value: The entered value was out of limits. • TEDS Error: Invalid value during a TEDS operation. • Busy Error: One or more M208A units are not ready. Make sure that all units are in the measuring mode. All menus must be closed. -
Page 47: Communication Via Ascii Commands
• No answer is sent if a channel number of a non-existing unit is addressed. • Commands are not accepted if the menus GAIN, SETUP or SENSOR are opened at the addressed M208A or an upstream unit in the chain. In this case the M208A will answer any command with BUSY. -
Page 48: Control Commands
Measuring display permanently displays the selected channel. Channel rotation #ccR c: channel number (01 to 64) in the range of the desired M208A* Activates channel rotation (to be stopped with #cC). This command is valid for all channels of the addressed M208A. - Page 49 * Commands addressing the entire M208A but not a single channel must be sent with an channel number in the range of the unit to be addressed, e.g. cc = 01 for...
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Page 50: Read Commands
Single integrator: 1. digit = S; 2. digit = I Double integrator: 1. digit = D; 2. digit = I Read instrument parameters #ccY c: channel number (01 to 64) in the range of the desired M208A* Answer: FffffffffffffffffffffBbKkPpCcZzJjjTttt f: instrument name (20 characters) b: baud rate (0 = 19200;... - Page 51 5 digits, e.g. “32512”, starting at channel 1 * Commands addressing the entire M208A but not a single channel must be sent with an channel number in the range of the unit to be addressed, e.g. cc = 01 for...
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Page 52: Ethernet Interface
For identification in the network also the MAC address is needed. It is the serial number of the M208A which cannot be edited by the user. The serial number or MAC address is displayed after pressing the key ◄ in measuring mode. - Page 53 Enter the IP address of the M208A in the browser's address line, for example http://192.168.178.30 Important: Leading zeros are stripped, e.g.“30” instead of “030”. Figure 53: HTML page sent from the M208A The M208A should answer now with an HTML page as shown in 53.The headline consists of the type (M208A) and the individually entered instrument name (section 12.5 on page 31).
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Page 54: Reset
Notice: The serial interface is disabled when using the Ethernet interface. 14. Reset If the M208A should not react on key or interface commands or show any other ab- normal behavior, you may restart the firmware by pressing the RESET key. Switch- ing off the power supply has the same effect. -
Page 55: Calibration
Select the channel to be calibrated (“Channel No.:”, 1 to 8) and the gain range (“Gain range”, 0/20/40/60 dB) by the ▲▼keys. Feed in the generator signal ac- cording to the display of the M208A, for example 50.00 mV in the gain range 40 dB. -
Page 56: Version And Serial Number
Press OK to confirm. 16. Version and Serial Number The version number of your M208A will be displayed after pressing the key ◄ in measuring mode. The format of the version number is xxx.yyy with the hardware version xxx and the firmware version yyy. The line beneath shows the firmware up- load date and the serial / MAC number which corresponds to the serial number label on the rear panel. - Page 57 Integration is only possible for acceleration input. Why doesn't the M208A react to com- Have you activated the serial interface mands from the serial interface? in the menu “Diverse Settings” / “Serial Interf.”?
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Page 58: Technical Data
18. 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 59 Warm-up time 5 min Serial interfaces RS-232 Master; RS-232 Slave; 19200 .. 115200 Bits/s 7 data bits; 1 stop bit; even parity; no flow control Number of slave units 7 Ethernet interface 10 Base-T; RJ45 socket Relay output 1 relay; trip value selectable for each channel change-over contact;...
- Page 60 According to EMC Directive 2014/30/EC and UK Electromagnetic Compatibility Regulations 2016 Product: 8 Channel IEPE Conditioner Type: M208A (from Ser. no. 160000) It is hereby certified that the above mentioned product complies with the demands pursuant to the following standards:...
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