JEA247ESAC - dolang
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1. An acquisition at 16 bit at least theoretically is 256 times worse than at 24 bit Signal noise ratio This parameter is very important as it can measure and tell us what is actually possible to discriminate a signal acquired in the presence of noise The problem to recover a signal from the noise is universal and always present in every situation If you remove the geophone and short circuit the inputs of the unit the signal only noise source is internal to the equipment or from electromagnetic interference and eventually due to the digital conversion process which gives rise to the quantization noise The quantization noise decreases with the increase of the bits of conversion This noise is reduced by the averages that are performed to get Fs from 32000Hz For example at 4000Hz there is a quantization noise slightly lower than 8000Hz This process of noise reduction is called Noise Shaping The equipment in question provides a value for this ratio better than 124dB for Fs 1 kHz or so which is a very good result If the noise was completely invalid and this was only the quantization noise with 24 bits for the relationship we have approximately 144dB which is a theoretical ideal value even remotely accessible This value is often not very seriously stated on many devices along with other parameters more or less invented Technical Data of JEA247ESAC gt WATER PROOF lt Sampling Frequency Fs2. 250Hz 500Hz 1000Hz 2000Hz 4000Hz 8000Hz 16000Hz 32000Hz Number of samples Fs gt 500Hz max Number 16384 Number of samples Fs 500Hz 250Hz max number 5M samples Sampling duration Fs 500Hz about 2h 50m 24 ch Fs 250Hz about 5h 40m 24 ch Trigger Each unit can be connected to a trigger wire of desired length to work in opening or closing contact Power Rechargeable battery unit included in USB RS485 box more than 7h autonomy with 24 units in continuous work First 24 ch powered by USB PC Bandwidth Up to 1 KHz 2 poles low pass filter DC component rejection Input impedence 1500 ohm Nyquist frequency 16000Hz at every Fs Units serially connected to PC by RS485 standard at 1MHz baudrate Software Application for Windows XP 7 and 8 allows nn easy setting of all acquisition parameters and produces a sgy seg2 file for further analisys Each Unit corresponding to a channel can be connected to a geophone with desired specifications
3. has in fact a progressive numeration from 1 to 24 25 to 48 49 to 72 etc being composed of 24 units You can connect to the MOM as many section as you desire for a maximum of 5 1 e 120 channels Here you can see a layout of several sections and their yellow geophones The last section of the seismic cable must have the termination inserted as shown Termination simply consists of a resistor of 120ohm necessary for correct line termination of cable If you do not terminate the line in this way signal reflections make impossible any transmition Between two section a Reapeter must be inserted The box bear a display for battery charge level verify that its value is more than 11v otherwise recharge it Respect the In Out order The new section must be connected to Out connector KA DOLANG OUT Geophyuical Repeater Then power up the power unit MOM Voltage should be about 11 12v If voltage on display is less than 11v recharge Each unit will begin to flash In this manual the term unit or channel denote the same thing as each box orange blue denotes a unit and also a channel Setting Parameters Once you have entered the correct number of the communication port enter the number of units in the box Geophones Number Before you acquire channels must be enabled and their identification number defined Select from the menu CHANNELS TEJEAZATESAC VII i Czy Fi OMETRY CHANNELS P aT LE RES
4. is the sampling frequency Fs from sampling frequency and resolution see below The reciprocal value of Fs is the sampling interval Ts by sampling time In the application in the Parameters window it acts directly on Fs Hz and as a result of Ts milliseconds To find out how long is the acquisition process the formula is as follows Acquisition Time Number of samples Fs or Acquisition Time Number of samples x Ts For example if I want a long acquisition time at a high Fs I expect a large number of samples It is not simple to deal with a large number of samples for cases where it is required a long period of acquisition a low Fs is used A basic rule of sampling is that Fs must be at least twice the highest frequency contained in the signal to be acquired Nyquist theorem If the rule is broken the acquired signal contains errors aliasing By the nature of the signals to be acquired which are coming from a geophone the spectrum barely reaches a few hundred Hz starting from a minimum of a few Hz depending on the geophone used thus not requiring a high Fs So in the case of a geophone that when triggered it is expected to provide signals until 300 400Hz the sampling frequency must be at least twice or 800Hz This consideration is only theoretical because in reality to acquire a signal that has any practical value you must acquire a much higher frequency Otherwise the available samples would b
5. or to keep to perform the acquisition process When the project will be terminated the processing software SMARTREFRACT will open automatically If the open windows shows empty go to menu Tools gt Plugins gt Installed and verify that all is installed SPECTRUM In the menu you can select Spectrum to carry out the spectral analysis of a track In following example has been selected track 1 Moving the mouse over the graph we can determine the value of the frequency accurately Samples GEOPHONES gt SPECTRUM E00 Frequency Number af a Being 2000Hz the acquisition frequency the maximum frequency of 1000Hz is displayed in the graph in accordance with the sampling theorem DISPLAY This menu is only active in the acquisition triggered Going to the menu Display you can choose the type of visualization of the acquired traces For example the following shows three different views normal mi JEA247ESAC V1 0 FILE STACKING GEOMETRY CHANNELS PARAMETERS DISPLAY SPECTRUM SMARTREFRACT EXIT s I GEOPHONES black JEA247ESAC V1 0 FILE STACKING GEOMETRY CHANNELS PARAMETERS DISPLAY SPECTRUM SNARTREFRACT EXT Blue Red JEAZATESAC V1 0 GEOPHONES Sampling Sampling PES CHANNEL 0 running comen n e A GE File menu From the File menu you can reload the acquisitions done in the Trig
6. Cambia impostazioni I Vedere anche Ulteriori informazioni online Centro operativo Windows Update Prestazioni del sistema cml 0 JC Bel Wale mean Een In this example port 20 can not be seen to change the number to go to USB Serial Port COM20 right click Properties Port Settings Advanced Number of the COM port then set a number less than or equal to 16 Important It is necessary to vary the value of latency time which is measured in msec It is related to data transmitted from device to PC The equipment connected to the USB socket will wait for a time equal to the time lag between one packet of data and the next It is necessary to lower this value to 1 msec Connect the USB cable to MOM it may be off Open the System control panel gt System gt Hardware gt Ports Com amp LPT and select the port number corresponding to the one used right click go to Properties Port Setting Advanced leid Md Cerca nel Pannello di controllo a GO iI Pannello di controllo Tutti gi elementi del Pannello di controlo Sistema SY SS lol xl Pagina in Fie Azone Visualizza dea ft aes MELMEESIESCIO Ler atterie Impostazioni avanzate COM15 n f or Protezior Numero porta COM eous H Impostaz Z Dispositivi di acquisizione Dimensione del trasferimento USB spositivi di sistema Selezionare la configurazione pi bassa per correggere i problemi a bassa v
7. ET CODE STACKI GEOPHONES Samples Number As you can see 24 channels have been labelled if you exit this setup will be remembered All 24 channels are enabled check below Click on the others cable sections to enable and number them in the same way The circle dot in the top of each unit represents the choice of the place to connect the trigger verify that some unit has this option checked otherwise you can t get any signal acquired In this example has been set a sampling frequency of 4000Hz for a number of samples per channel equal to 256 open the Parameters window to set As is shown the acquisition lasts for 64 msec In fact 256 samples 4000Hz 64 msec Ty JEA247ESAC VII ia sl x FILE RESET CODE STACKING GEOMETRY CHANNELS PARAMETERS DISPLAY SPECTRUM REFRACTION BIT Samples GEOPHONES P Autorange A 10 A 100 z sec A 1 A 1000 Fs 4000 Hz H Trigger contact closing Acquisition Parameters It is possible to see in real time the system acquires while it acquires all the channels set but first remember to Set all Channels and to check the option for trigger By default the amplification is autoranging then you will see even the slightest signal Press now GO running If there are not connected geophones what you will see is the background noise of the apparatus All graphs will be updated as fast as lower is the number of samples set now 256 as the s
8. SZ DOLAN Geophysical JEA247ESAC SEISMOGRAPH User Manual Software Installation Refer to the folder directory of the installation file whose name is Installation Disk JEA24TESAC In it there is a file with the name Installing USB Drivers FTDI pdf Open it and follow the prompts to install the USB drivers needed to operate the equipment After installation of the driver run the installation file JEA247ESACSetup exe Will be created in C drive default JEA247ESAC folder with inside the application file with the name JEA247ESAC exe Since the application also makes use of a software for geoseismic interpretation SmartRefract wich makes use of acquired data you need to copy a folder in the following way Go to the installation file Setup Disk JEA24TESAC in which is contained the directory SmartRefract Copy this folder inside the directory created by the installation program on your computer which is usually c JEA247ESAC Then go to www java com and download and install java in the computer FIRST CONNECTION Please read carefully this section After you have installed the USB driver and application JEA247ESAC see file Install USB Driver FTDI pdf connect the power unit MOM to your PC using the USB wire MOM Unit MOM Unit connected to PC and cable Verify PORT Launch the application jea247esac exe that should be in directory JEA247ESAC Once launched you will noti
9. ampling and receiving process will lasts less with less data To quit the process press STOP units will flash in a different way and after about 2 seconds the system will be ready for a new command The command GO running is usefull to verify connection between units and geophones Retriving files On the upper left corner the menu FILE allows to retrive an old trigger acquisition Choose the appropriate txt file and it will be loaded and all parameters set to the new values Acquisition with Trigger For operation with trigger sampling frequency must be set equal to 1000Hz 2000Hz 4000Hz 8000Hz 16000Hz 32000Hz In the Parameters window define whether the trigger signal will work in opening eg Explosion or closing eg Hammer of the contact Then verify that a unit as been set as trigger unit For example for a seismic refraction can be suitable the value of 512 samples and sampling frequency of 2000Hz TRIGGER and press the GO button Window of geometry will show Ty JEA247ESAC VII ia a x FILE RESET CODE STACKING GEOMETRY CHANNELS PARAMETERS DISPLAY SPECTRUM REFRACTION EXT GEOPHONES Continuous samplin Samples Number i I EGR cH 5 GEOMETI aa Shot to REG Shot to first elt spacing peed El an 460 m Ok 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 19 70 71 72 7374 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 Set the
10. ce something like this mo JEA247ESAC V1 0 Ed GLM a SSL me Samples GEOPHONES ENE zen mm In the green box appears the RS232 ports available on PC which in this example are the number 1 14 and 16 Port numbers range from 1 to 16 To remove ambiguity about which port is dedicated to the equipment just disconnect the USB port and run the software again The correct number will be that disappeared The other parameters are the default ones Note It still possible that at the first plugging of the device MOM the operating system decides to assign a different number over 16 to the port In this case the port would not appear in the green box and you have to change its number Go to the Control Panel gt System Device Manager Ports COM amp LPT 18 xj Cerca nel Pannello di controllo a esimHmt EP Gestione g moos Ei Batterie remota ah presta fq Computer Protezonl tx Controller audio video e giochi Impostaz c Controller IDE ATA ATAPI E Controller USB Universal Serial Bus EE Dispositivi di acquisizione immagini j Dispositivi di sistema E Driver delle tecnologie di memoria BU Human Interface Device HID El Mouse e altri dispositivi di puntamento ETF Porte COM e LPT YP MSP FET430UIF CDC COM8 F USB Serial Port COM20 EED Processori Radio Bluetooth EBS Schede di rete Ei Schede video CES 8 Ecg Unit disco lt Q Unit DVD CD ROM GP
11. distance between geophones which in the example is four meters and the position of the trigger with respect to the first unit now 46 meters to the right of first unit By clicking OK the geometry disappears and a message WAITING FOR TRIGGER will begin to flash The system is waiting for a trigger event but if for some reason you want to leave this condition you just have to click on exit When the trigger acquisition is finished the application will ask whether to save the acquired data If you decide to save two versions of the file will be saved one with extension Sg2 and the other with extension txt File txt will be useful in case you want to review recently file previously saved Below is an example of acquisition with 96 channels renee sat Vi Li as FILE RESET CODE STACKING GEOMETRY CHANNELS PARAMETERS DISPLAY SPECTRUM REFRACTION EXIT Moving the mouse over a track and clicking in the CH box will be displayed its number Moving the mouse over a point in a track in a window will be visible the relative time from trigger instant Acquisition without triggering If the sampling frequency is equal to 500Hz or 250Hz the trigger function is disabled but the acquisition is possible for a long time for 24 channels maximum T
12. e too few to easily reconstruct the original signal The application JEA247ESAC acquires always at Fs 32000Hz The lower sample rates are derived from the actual 32000Hz averaging For example the frequency of 4000 Hz is obtained from the average of 8 samples This process of downsampling carries out an average on the signal that corresponds to a low pass filtering which is useful to diminish any higher frequencies and noise present Nevertheless to acquire 250Hz the minimum expected Fs exposes us to possible aliasing errors in case in the signal was a strong component over the 125Hz A hardware filter on this unit provides to eliminate mitigate frequencies not useful coming from geophone In sampling without trigger even if you can acquire at 250Hz it is better to opt for the higher frequency of 500Hz to avoid the danger of aliasing error Resolution The resolution is determined by the number of bits of the AD converter The higher the resolution the more the sampling system can see small signals JEA247ESAC uses a 24 bit converter so if it is assumed that the geophone can give a maximum signal between 1V and 1V matching the range of AD converter the theoretical minimum measurable signal is 2volt 2 24 119 NV 0 119 millivolts microvolts 0 000119 0 0000001 19 volts Although this measure is theoretical and is incredibly low the amount of bits gives us another factor to measure the goodness of an acquisition
13. elocit di trasferimento iver delle tecnologie di r man Interface Device Selezonare la configurazione pi alta per il trasferimento veloce Mouse e altri dispositivi di See Ricezione Bytes lt Ef Porte COM e LPT Rino va i F USB serial Port COM Trasmissione 5 asta Bytes 4096 Radio Bluetooth gt Schede di rete p Opzioni BM Opzioni varie La Schede video Selezionare la configurazione pi bassa per risolvere i EE Schermi EAA a bassa panan Enumeratore seriale B Tastiere Ecg Unit disco Tempo di latenza msec 1 z Bintangs Egli Unit DVD CD ROM Cancella se l alimentazione spenta Gear Cambia impostazioni pee Evento su una rimozione inaspettata Tempo minimo di tmeoutin lettura g Seleziona RTS sulla chiusura Disabilitare il controller del modem all accensione Tempo minimo di timeout in scrittura cont 1 sed el Vedere anche Ulteriori informazioni online Centro operativo Windows Update Prestazioni del sistema es 0 SIC Bl S mi mE ee The latency time is now set to 1 msec In the case of transmission from a PC to the device the protocol is already structured to transmit packets employing a time of 1 msec or greater Connecting Sections The JEA247ESAC consists of 1 or more cable sections each section is composed of 24 units channels The first unit is characterized by a number starting with 1 Each cable section
14. ger mode Go to the folder where you saved the files relating to previous acquisitions and download the file with the extension txt Files xxx txt and data_trigger txt The application creates for each acquisition with trigger a file data_trigger txt and another XXx Sgy and xxx txt The name xxx must be provided by the user File data_trigger txt is updated every acquisition and located in JEA247ESAC directory it is necessary for internal use In running operation any file is saved SMARTREFRACT See www vs30 it_ cof smartRefract Upega 201306052037 File Edit Impostazioni Navigate View Tools Window Help ald Finestra di benvenuto File recenti Accedi all home page Licenza attiva Upega 4 start Be F Programmi VB6 JE TE JEA247ESAC Manual m ESAC soft Visu About this software is free for refraction postprocessing GRM method and also the customer have the right for internet assistance for any problems concerning postprocessing Special DOLANG Service Is available to make the processing upon payment of a small amount Sampling Rate To perform a correct acquisition should be thoroughly learned what it means signal what is its spectrum filtering reconstruction of signal from its samples sample rate etc otherwise you may set the parameters without understanding why and do not correctly interpret what happens The basic parameters of the process of acquisition
15. he memory resides in the hard disk of the PC Acquisition time may be Sampling frequency of 500Hz 2 hours 51 max Sampling frequency of 250Hz 5 hours 42 max To start Acquisitions without trigger select the Continuous sampling In the following example has been set a sampling frequency of 500Hz for a time of acquisition of 20m and 5 sec ES JEA247ESAC V1 0 m lt lt Clicking on START acquisition begins and a progress bar will indicate the progress of the process At the end you have to save the file in SGY format STACKING In the goal of reducing the Gaussian noise it is theoretically sufficient to mediate The STACKING do this as it lets you add together the traces acquired through trigger at successive times The resulting signal should be more clean as long as the trigger is always carried out in the same exact condition and nothing has changed in the geometry To acquire with the method Stacking go to the menu and select stacking The graph will become blue At every triggering tracks will be added together After each triggering will be shown Keep on staking Answer no it ends the process of stacking and the file acquisition can be saved REFRACTION From Menu select REFRACTION You are asked to write the project name and then to begin acquiring in trigger mode After each acquisition enter the file name and save it if satisfied Then you have to decide if the project is ended
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